Internet Engineering Task Force Saravanan Shanmugham Internet-Draft Cisco Systems Inc. draft-ietf-speechsc-mrcpv2-06 Daniel C. Burnett Expires: August 20, 2005 Nuance Communications February 20, 2005 Media Resource Control Protocol Version 2(MRCPv2) Status of this Memo By submitting this Internet-Draft, we certify that any applicable patent or other IPR claims of which we are aware have been disclosed, and any of which we become aware will be disclosed, in accordance with RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt . The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html . This Internet-Draft will expire on August 20, 2005. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document describes a proposal for a Media Resource Control Protocol Version 2 (MRCPv2) and aims to meet the requirements specified in the SPEECHSC working group requirements document. It is based on the Media Resource Control Protocol (MRCP), also called S. Shanmugham, et. al. Page 1 MRCPv2 Protocol February, 2005 MRCPv1 developed jointly by Cisco Systems, Inc., Nuance Communications, and Speechworks Inc. The MRCPv2 protocol will control media service resources like speech synthesizers, recognizers, signal generators, signal detectors, fax servers etc. over a network. This protocol depends on a session management protocol such as the Session Initiation Protocol (SIP) to establish a separate MRCPv2 control session between the client and the server. It also depends on SIP to establish the media pipe and associated parameters between the media source or sink and the media server. Once this is done, the MRCPv2 protocol exchange can happen over the control session established above allowing the client to command and control the media processing resources that may exist on the media server. Table of Contents Status of this Memo..............................................1 Copyright Notice.................................................1 Abstract.........................................................1 Table of Contents................................................2 1. Introduction:.............................................4 2. Notational Convention.....................................5 3. Architecture:.............................................6 3.1. Server and Resource Addressing............................8 4. MRCPv2 Protocol Basics....................................8 4.1. Connecting to the Server..................................8 4.2. Managing Resource Control Channels........................9 4.3. Media Streams and RTP Ports..............................15 4.4. MRCPv2 Message Transport.................................16 5. MRCPv2 Specification.....................................17 5.1. Request..................................................18 5.2. Response.................................................19 5.3. Event....................................................20 6. MRCP Generic Features....................................21 6.1. Generic Message Headers..................................21 6.2. SET-PARAMS...............................................30 6.3. GET-PARAMS...............................................31 7. Resource Discovery.......................................31 8. Speech Synthesizer Resource..............................33 8.1. Synthesizer State Machine................................33 8.2. Synthesizer Methods......................................34 8.3. Synthesizer Events.......................................34 8.4. Synthesizer Header Fields................................34 8.5. Synthesizer Message Body.................................41 8.6. SPEAK....................................................43 8.7. STOP.....................................................45 8.8. BARGE-IN-OCCURRED........................................46 8.9. PAUSE....................................................47 8.10. RESUME...................................................48 S Shanmugham IETF-Draft Page 2 MRCPv2 Protocol February, 2005 8.11. CONTROL..................................................50 8.12. SPEAK-COMPLETE...........................................51 8.13. SPEECH-MARKER............................................52 8.14. DEFINE-LEXICON...........................................53 9. Speech Recognizer Resource...............................54 9.1. Recognizer State Machine.................................55 9.2. Recognizer Methods.......................................55 9.3. Recognizer Events........................................56 9.4. Recognizer Header Fields.................................56 9.5. Recognizer Message Body..................................71 9.6. Natural Language Semantic Markup Language................75 9.7. Enrollment Results.......................................83 9.8. DEFINE-GRAMMAR...........................................85 9.9. RECOGNIZE................................................88 9.10. STOP.....................................................91 9.11. GET-RESULT...............................................93 9.12. START-OF-SPEECH..........................................93 9.13. START-INPUT-TIMERS.......................................94 9.14. RECOGNITION-COMPLETE.....................................94 9.15. START-PHRASE-ENROLLMENT..................................96 9.16. ENROLLMENT-ROLLBACK......................................97 9.17. END-PHRASE-ENROLLMENT....................................98 9.18. MODIFY-PHRASE............................................98 9.19. DELETE-PHRASE............................................99 9.20. INTERPRET................................................99 9.21. INTERPRETATION-COMPLETE.................................100 9.22. DTMF Detection..........................................101 10. Recorder Resource.......................................102 10.1. Recorder State Machine..................................102 10.2. Recorder Methods........................................102 10.3. Recorder Events.........................................102 10.4. Recorder Header Fields..................................102 10.5. Recorder Message Body...................................107 10.6. RECORD..................................................107 10.7. STOP....................................................108 10.8. RECORD-COMPLETE.........................................109 10.9. START-INPUT-TIMERS......................................109 11. Speaker Verification and Identification.................111 11.1. Speaker Verification State Machine......................112 11.2. Speaker Verification Methods............................112 11.3. Verification Events.....................................113 11.4. Verification Header Fields..............................113 11.5. Verification Result Elements............................121 11.6. START-SESSION...........................................125 11.7. END-SESSION.............................................126 11.8. QUERY-VOICEPRINT........................................126 11.9. DELETE-VOICEPRINT.......................................127 11.10. VERIFY..................................................128 11.11. VERIFY-FROM-BUFFER......................................128 11.12. VERIFY-ROLLBACK.........................................131 11.13. STOP....................................................132 S Shanmugham IETF-Draft Page 3 MRCPv2 Protocol February, 2005 11.14. START-INPUT-TIMERS......................................133 11.15. VERIFICATION-COMPLETE...................................133 11.16. START-OF-SPEECH.........................................134 11.17. CLEAR-BUFFER............................................134 11.18. GET-INTERMEDIATE-RESULT.................................134 12. Security Considerations.................................135 13. IANA Considerations.....................................135 13.1. New registries..........................................135 13.2. NLSML-related registrations.............................137 13.3. session URL scheme registration.........................139 13.4. SDP parameter registrations.............................140 14. Examples:...............................................141 14.1. Message Flow............................................141 14.2. Recognition Result Examples.............................149 Normative Reference............................................153 Appendix.......................................................155 A.1 ABNF Message Definitions...................................155 A.2 XML Schema and DTD.........................................168 A.2.1 Recognition Results......................................168 A.2.2 Enrollment Results.......................................170 A.2.3 Verification Results.....................................171 Full Copyright Statement.......................................175 Intellectual Property..........................................175 Contributors...................................................176 Acknowledgements...............................................176 Editors' Addresses.............................................177 1. Introduction: The MRCPv2 protocol is designed for a client device to control media processing resources on the network allowing to process and audio/video stream. Some of these media processing resources could be speech recognition, speech synthesis engines, speaker verification or speaker identification engines. This allows a vendor to implement distributed Interactive Voice Response platforms such as VoiceXML [7] browsers. The protocol requirements of SPEECHSC require that the protocol is capable of reaching a media processing server and setting up communication channels to the media resources, to send/recieve control messages and media streams to/from the server. The Session Initiation Protocol (SIP) protocol described in [4] meets these requirements and is used to setup and tear down media and control pipes to the server. In addition, the SIP re-INVITE can be used to change the characteristics of these media and control pipes mid- session. The MRCPv2 protocol hence is designed to leverage and build upon a session management protocols such as Session Initiation Protocol (SIP) and Session Description Protocol (SDP). SDP is used to describe the parameters of the media pipe associated with that S Shanmugham IETF-Draft Page 4 MRCPv2 Protocol February, 2005 session. It is mandatory to support SIP as the session level protocol to ensure interoperability. Other protocols can be used at the session level by prior agreement. The MRCPv2 protocol depends on SIP and SDP to create the session, and setup the media channels to the server. It also depends on SIP and SDP to establish MRCPv2 control channels between the client and the server for each media processing resource required for that session. The MRCPv2 protocol exchange between the client and the media resource can then happen on that control channel. The MRCPv2 protocol exchange happening on this control channel does not change the state of the SIP session, the media or other parameters of the session SIP initiated. It merely controls and affects the state of the media processing resource associated with that MRCPv2 channel. The MRCPv2 protocol defines the messages to control the different media processing resources and the state machines required to guide their operation. It also describes how these messages are carried over a transport layer such as TCP, TLS or, in the future, SCTP. 2. Notational Convention The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this document are to be interpreted as described in RFC 2119[9]. Since many of the definitions and syntax are identical to HTTP/1.1, this specification only points to the section where they are defined rather than copying it. For brevity, [HX.Y] is to be taken to refer to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [1]). All the mechanisms specified in this document are described in both prose and an augmented Backus-Naur form (ABNF). It is described in detail in RFC 2234 [3]. The complete message format in ABNF form is provided in Appendix section 12.1 and is the normative format definition. Media Resource An entity on the MRCP Server that can be controlled through the MRCP protocol MRCP Server Aggregate of one or more "Media Resource" entities on a Server, exposed through the MRCP protocol.("Server" for short) MRCP Client An entity controlling one or more Media Resources through the MRCP protocol. ("Client" for short) S Shanmugham IETF-Draft Page 5 MRCPv2 Protocol February, 2005 3. Architecture: The system consists of a client that requires the generation of media streams or requires the processing of media streams and a media resource server that has the resources or engines to process or generate these streams. The client establishes a session using SIP and SDP with the server to use its media processing resources. A SIP URI refers to the MRCPv2 server. The session management protocol (SIP) will use SDP with the offer/answer model described RFC 3264 to describe and setup the MRCPv2 control channels. Separate MRCPv2 control channels are need for controlling the different media processing resources associated with that session. Within a SIP session, the individual resource control channels for the different resources are added or removed through the SDP offer/answer model and the SIP re-INVITE dialog. The server, through the SDP exchange, provides the client with a unique channel identifier and a TCP port number. The client MAY then open a new TCP connection with the server using this port number. Multiple MRCPv2 channels can share a TCP connection between the client and the server. All MRCPv2 messages exchanged between the client and the server will also carry the specified channel identifier that MUST be unique among all MRCPv2 control channels that are active on that server. The client can use this channel to control the media processing resource associated with that channel. The session management protocol (SIP) will also establish media pipes between the client (or source/sink of media) and the MRCP server using SDP m-lines. A media pipe maybe shared by one or more media processing resources under that SIP session or each media processing resource may have its own media pipe. MRCPv2 client MRCPv2 Media Resource Server |--------------------| |-----------------------------| ||------------------|| ||---------------------------|| || Application Layer|| || TTS | ASR | SV | SI || ||------------------|| ||Engine|Engine|Engine|Engine|| ||Media Resource API|| ||---------------------------|| ||------------------|| || Media Resource Management || || SIP | MRCPv2 || ||---------------------------|| ||Stack | || || SIP | MRCPv2 || || | || || Stack | || ||------------------|| ||---------------------------|| || TCP/IP Stack ||----MRCPv2---|| TCP/IP Stack || || || || || ||------------------||-----SIP-----||---------------------------|| |--------------------| |-----------------------------| | / S Shanmugham IETF-Draft Page 6 MRCPv2 Protocol February, 2005 SIP / | / |-------------------| RTP | | / | Media Source/Sink |-------------/ | | |-------------------| Fig 1: Architectural Diagram MRCPv2 Media Resource Types: The MRCP server may offer one or more of the following media processing resources to its clients. Basic Synthesizer A speech synthesizer resource with very limited capabilities, that can be achieved through the playing out concatenated audio file clips. The speech data is described as SSML data but with limited support for its elements. It MUST support <speak>, <audio>, <say-as> and <mark> tags in SSML. Speech Synthesizer A full capability speech synthesizer capable of rendering regular speech and SHOULD have full SSML support. Recorder A resource capable of recording audio and saving it to an URI. It also has some end-pointing capabilities for detecting beginning speech and silence at the end of recording. DTMF Recognizer A limited DTMF only recognizer that is able to recognize DTMF digits in the input stream to match supplied digit grammar. It could also do a semantic interpretation based on semantic tags in the grammar. Speech Recognizer A full speech recognizer that is capable of receiving audio and interpreting it to recognition results. It also has a natural language semantic interpreter to post process the recognized data according to the semantic data in the grammar and provide semantic results along with the recognized input. The recognizer may also S Shanmugham IETF-Draft Page 7 MRCPv2 Protocol February, 2005 support enrolled grammars, where the client can enroll and create new personal grammars for use in future grammars. Speaker Verification A resource capable of verifying the authenticity of a person by matching his voice to a saved voice-print. This may also involve matching the callers voice with more than one voice-print, also called multi-verification or speaker identification. 3.1. Server and Resource Addressing The MRCPv2 server as a whole is a generic SIP server and addressed by a specific SIP URL registered by the server. Example: sip:mrcpv2@mediaserver.com 4. MRCPv2 Protocol Basics MRCPv2 requires the use of a connection oriented transport layer protocol such as TCP or SCTP to guarantee reliable sequencing and delivery of MRCPv2 control messages between the client and the server. If security is needed a TLS connection is used to carry MRCPv2 messages. One or more TCP, TLS or SCTP(in the future) connections between the client and the server can be shared between different MRCPv2 channels to the server. The individual messages carry the channel identifier to differentiate messages on different channels. The message format for MRCPv2 is text based with mechanisms to carry embedded binary data. This allows data like recognition grammars, recognition results, synthesizer speech markup etc. to be carried in the MRCPv2 message between the client and the server resource. The protocol does not address session and media establishment and management and relies of SIP and SDP to do this. 4.1. Connecting to the Server The MRCPv2 protocol depends on a session establishment and management protocol such as SIP in conjunction with SDP. The client finds and reaches a MRCPv2 server across the SIP network using the INVITE and other SIP dialog exchanges. The SDP offer/answer exchange model over SIP is used to establish resource control channels for each resource. The SDP offer/answer exchange is also used to establish media pipes between the source or sink of audio and the server. S Shanmugham IETF-Draft Page 8 MRCPv2 Protocol February, 2005 4.2. Managing Resource Control Channels The client needs a separate MRCPv2 resource control channel to control each media processing resource under the SIP session. A unique channel identifier string identifies these resource control channels. The channel identifier string consists of a hexadecimal number specifying the channel ID followed by a string token specifying the type of resource separated by an "@". The server generates the hexadecimal channel ID and MUST make sure it does not clash with any other MRCP channel allocated to that server. MRCPv2 defines the following type of media processing resources. Additional resource types, their associated methods/events and state machines can be added by future specification proposing to extend the capabilities of MRCPv2. Resource Type Resource Description speechrecog Speech Recognizer dtmfrecog DTMF Recognizer speechsynth Speech Synthesizer basicsynth Basic Synthesizer speakverify Speaker Verification recorder Speech Recorder The SIP INVITE or re-INVITE dialog exchange and the SDP offer/answer exchange it carries, will contain m-lines describing the resource control channel it wants to allocate. There MUST be one SDP m-line for each MRCPv2 resource that needs to be controlled. This m-line will have a media type field of "application" and a transport type field of "TCP/MRCPv2", "TCP/TLS/MRCPv2". The usage of SCTP with MRCPv2 will be addressed in a separate draft. The port number field of the m-line MUST contain the discard port of the transport protocol (say port 9 for TCP) in the SDP offer from the client and MUST contain the TCP listen port on the server in the SDP answer. The client may then setup a TCP or TLS connection to that server port or share an already established connection to that port. The format field of the m-line is not used and MUST be left empty. The client must specify the resource type identifier in the resource attribute associated with the control m-line of the SDP offer. The server MUST respond with the full Channel-Identifier (which includes the resource type identifier and an unique hexadecimal identifier), in the "channel" attribute associated with the control m-line of the SDP answer. All servers MUST support TLS, SHOULD support TCP and MAY support SCTP(in the future) and it is up to the client to choose which mode of transport it wants to use for an MRCPv2 session. When using TCP, TLS the m-lines MUST conform to IETF draft[20] which describes the usage of SDP for connection oriented transport. When using TLS the SDP m-line for the control pipe MUST conform to the IETF draft[21] in addition to the IETF draft[20]. IETF draft[21] specifies the S Shanmugham IETF-Draft Page 9 MRCPv2 Protocol February, 2005 usage of SDP for establishing a secure connection oriented transport over TLS. When the client wants to add a media processing resource to the session, it MUST initiate a re-INVITE dialog. The SDP offer/answer exchange contained in this SIP dialog will contain an additional control m-line for the new resource that needs to be allocated. The server, on seeing the new m-line, will allocate the resource and respond with a corresponding control m-line in the SDP answer response. The a=setup attribute as described in [20] MUST be "active" for the offer from the client and MUST be "passive" for the answer from the MRCP server. The a=connection attribute MUST have a value of "new" on the very first control m-line offer from the client to a MRCP server. Subsequent control m-lines offers from the client to the MRCP server MAY contain "new" or "existing", depending on whether the client wants to share a existing connection oriented pipe. The value of "existing" tells the server that the client wants to reuse an existing transport connection between the client and the server. The server can respond with a value of "existing", if wants to allow sharing of existing pipes or can reply with a value of "new", in which case the client MUST initiate new connection oriented pipe. When the client wants to de-allocate the resource from this session, it MUST initiate a SIP re-INVITE dialog with the server and MUST offer the control m-line with a port 0. The server MUST then answer the control m-line with a response of port 0. This de-allocates the usage of the associated MRCP identifier and resource. But may not close the TCP, SCTP or TLS connection if it is currently being shared among multiple MRCP channels. When all MRCP channels that may be sharing the connection are released and the associated SIP connections are closed, the client or server disconnect the shared connection oriented pipe. Example 1: This exchange adds a resource control channel for a synthesizer. Since a synthesizer would be generating an audio stream, this interaction also creates a receive-only audio stream for the server to send audio to. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314161 INVITE Contact: <sip:sarvi@cisco.com> S Shanmugham IETF-Draft Page 10 MRCPv2 Protocol February, 2005 Content-Type: application/sdp Content-Length: ... v=0 o=sarvi 2890844526 2890842808 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 9 TCP/MRCPv2 a=setup:active a=connection:new a=resource:speechsynth a=cmid:1 m=audio 49170 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=recvonly a=mid:1 S->C: SIP/2.0 200 OK Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314161 INVITE Contact: <sip:sarvi@cisco.com> Content-Type: application/sdp Content-Length: ... v=0 o=sarvi 2890844526 2890842808 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 32416 TCP/MRCPv2 a=setup:passive a=connection:new a=channel:32AECB234338@speechsynth a=cmid:1 m=audio 48260 RTP/AVP 00 96 a=rtpmap:0 pcmu/8000 a=sendonly a=mid:1 C->S: ACK sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 S Shanmugham IETF-Draft Page 11 MRCPv2 Protocol February, 2005 CSeq: 314162 ACK Content-Length: 0 Example 2: This exchange continues from example 1 and allocates an additional resource control channel for a recognizer. Since a recognizer would need to receive an audio stream for recognition, this interaction also updates the audio stream to sendrecv making it a 2-way audio stream. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314163 INVITE Contact: <sip:sarvi@cisco.com> Content-Type: application/sdp Content-Length: ... v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 9 TCP/MRCPv2 a=setup:active a=connection:existing a=resource:speechrecog a=cmid:1 m=application 9 TCP/MRCPv2 a=setup:active a=connection:existing a=resource:speechsynth a=cmid:1 m=audio 49170 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=rtpmap:96 telephone-event/8000 a=fmtp:96 0-15 a=sendrecv a=mid:1 S->C: SIP/2.0 200 OK Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 S Shanmugham IETF-Draft Page 12 MRCPv2 Protocol February, 2005 CSeq: 314163 INVITE Contact: <sip:sarvi@cisco.com> Content-Type: application/sdp Content-Length: 131 v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 32416 TCP/MRCPv2 a=setup:passive a=connection:existing a=channel:32AECB234338@speechrecog a=cmid:1 m=application 32416 TCP/MRCPv2 a=setup:passive a=connection:existing a=channel:32AECB234339@speechsynth a=cmid:1 m=audio 48260 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=rtpmap:96 telephone-event/8000 a=fmtp:96 0-15 a=sendrecv a=mid:1 C->S: ACK sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314164 ACK Content-Length: 0 Example 3: This exchange continues from example 2 and de-allocates recognizer channel. Since a recognizer would not need to receive an audio stream any more, this interaction also updates the audio stream to recvonly. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 S Shanmugham IETF-Draft Page 13 MRCPv2 Protocol February, 2005 Call-ID: a84b4c76e66710 CSeq: 314163 INVITE Contact: <sip:sarvi@cisco.com> Content-Type: application/sdp Content-Length: ... v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 0 TCP/MRCPv2 a=resource:speechrecog a=cmid:1 m=application 9 TCP/MRCPv2 a=resource:speechsynth a=cmid:1 m=audio 49170 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=recvonly a=mid:1 S->C: SIP/2.0 200 OK Via: SIP/2.0/TCP client.atlanta.example.com:5060; branch=z9hG4bK74bf9 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314163 INVITE Contact: <sip:sarvi@cisco.com> Content-Type: application/sdp Content-Length: 131 v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=- c=IN IP4 224.2.17.12 m=application 0 TCP/MRCPv2 a=channel:32AECB234338@speechrecog a=cmid:1 m=application 32416 TCP/MRCPv2 a=channel:32AECB234339@speechsynth a=cmid:1 m=audio 48260 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=sendonly a=mid:1 C->S: ACK sip:mresources@mediaserver.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060; S Shanmugham IETF-Draft Page 14 MRCPv2 Protocol February, 2005 branch=z9hG4bK74bf9 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314164 ACK Content-Length: 0 4.3. Media Streams and RTP Ports The client or the server would need to add audio (or other media) pipes between the client and the server and associate them with the resource that would process or generate the media. One or more resources could be associated with a single media channel or each resource could be assigned a separate media channel. For example, a synthesizer and a recognizer could be associated to the same media pipe(m=audio line), if it is opened in "sendrecv" mode. Alternatively, the recognizer could have its own "sendonly" audio pipe and the synthesizer could have its own "recvonly" audio pipe. The association between control channels and their corresponding media channels is established through the mid attribute defined in RFC 3388[20]. If there are more than 1 audio m-line, then each audio m-line MUST have a "mid" attribute. Each control m-line MUST have a "cmid" attribute that matches the "mid" attribute of the audio m- line it is associated with. cmid-attribute = "a=cmid:" identification-tag identification-tag = token A single audio m-line can be associated with multiple resources or each resource can have its own audio m-line. For example, if the client wants to allocate a recognizer and a synthesizer and associate them to a single 2-way audio pipe, the SDP offer should contain two control m-lines and a single audio m-line with an attribute of "sendrecv". Each of the control m-lines should have a "cmid" attribute whose value matches the "mid" of the audio m-line. If the client wants to allocate a recognizer and a synthesizer each with its own separate audio pipe, the SDP offer would carry two control m-lines (one for the recognizer and another for the synthesizer) and two audio m-lines (one with the attribute "sendonly" and another with attribute "recvonly"). The "cmid" attribute of the recognizer control m-line would match the "mid" value of the "sendonly" audio m-line and the "cmid" attribute of the synthesizer control m-line would match the "mid" attribute of the "recvonly" m-line. When a server receives media(say audio) on a media pipe that is associated with more than one media processing resource, it is the responsibility of the server to receive and fork it to the resources S Shanmugham IETF-Draft Page 15 MRCPv2 Protocol February, 2005 that need it. If the multiple resources in a session are generating audio (or other media), that needs to be sent on a single associated media pipe, it is the responsibility of the server to mix the streams before sending on the media pipe. The media stream in either direction may contain more than one Synchronized Source (SSRC) identifier due to multiple sources contributing to the media on the pipe and the client or server SHOULD be able to deal with it. If a server does not have the capability to mix or fork media, in the above cases, then the server SHOULD disallow the client from associating multiple such resources to a single audio pipe, by rejecting the SIP INVITE with a SIP 501 "Not Implemented" error. 4.4. MRCPv2 Message Transport The MRCPv2 resource messages defined in this document are transported over a TCP, TLS or SCTP(in the future) pipe between the client and the server. The setting up of this transport pipe and the resource control channel is discussed in Section 4.2. Multiple resource control channels between a client and a server that belong to different SIP sessions can share one or more TLS, TCP or SCTP pipes between them and the server and client MUST support this operation. The individual MRCPv2 messages carry the MRCPv2 channel identifier in their Channel-Identifier header field, which MUST be used to differentiate MRCPv2 messages from different resource channels. All MRCPv2 servers MUST support TLS, SHOULD support TCP and MAY support SCTP(in the future) and it is up to the client to choose which mode of transport it wants to use for an MRCPv2 session. Example 1: C->S: MRCP/2.0 483 SPEAK 543257 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> S Shanmugham IETF-Draft Page 16 MRCPv2 Protocol February, 2005 <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C: MRCP/2.0 81 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth S->C: MRCP/2.0 89 SPEAK-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Most examples from here on show only the MRCPv2 messages and do not show the SIP messages and headers that may have been used to establish the MRCPv2 control channel. 5. MRCPv2 Specification The MRCPv2 PDU is textual using an ISO 10646 character set in the UTF-8 encoding (RFC 2044) to allow many different languages to be represented. However, to assist in compact representations, MRCPv2 also allows other character sets such as ISO 8859-1 to be used when desired. The MRCPv2 protocol headers(the first line of an MRCP message) and field names use only the US-ASCII subset of UTF-8. Internationalization only applies to certain fields like grammar, results, speech markup etc, and not to MRCPv2 as a whole. Lines are terminated by CRLF. Also, some parameters in the PDU may contain binary data or a record spanning multiple lines. Such fields have a length value associated with the parameter, which indicates the number of octets immediately following the parameter. All MRCPv2 messages, responses and events MUST carry the Channel- Identifier header field in it, for the server or client to differentiate messages from different control channels that may share the same transport connection. The MRCPv2 message set consists of requests from the client to the server, responses from the server to the client and asynchronous events from the server to the client. All these messages consist of a start-line, one or more header fields (also known as "headers"), an empty line (i.e. a line with nothing preceding the CRLF) indicating the end of the header fields, and an optional message body. generic-message = start-line message-header CRLF [ message-body ] S Shanmugham IETF-Draft Page 17 MRCPv2 Protocol February, 2005 start-line = request-line / response-line / event-line message-header = 1*(generic-header / resource-header) resource-header = recognizer-header / synthesizer-header / recorder-header / verifier-header The message-body contains resource-specific and message-specific data that needs to be carried between the client and server as a MIME entity. The information contained here and the actual MIME- types used to carry the data are specified later when addressing the specific messages. If a message contains data in the message body, the header fields will contain content-headers indicating the MIME-type and encoding of the data in the message body. 5.1. Request A MRCPv2 request consists of a Request line followed by message headers and an optional message body containing data specific to the request message. The Request message from a client to the server includes within the first line the method to be applied, a method tag for that request and the version of protocol in use. request-line = mrcp-version SP message-length SP method-name SP request-id CRLF The mrcp-version field is the MRCPv2 protocol version that is being used by the client. Request, response and event messages include the version of MRCP in use, and follow [H3.1] (with HTTP replaced by MRCP, and HTTP/1.1 replaced by MRCP/2.0) regarding version ordering, compliance requirements, and upgrading of version numbers. To be compliant with this specification, applications sending MRCP messages MUST include a mrcp-version of "MRCP/2.0". mrcp-version = "MRCP" "/" 1*DIGIT "." 1*DIGIT The message-length field specifies the length of the message, including the start-line, and MUST be the 2nd token from the beginning of the message. This is to make the framing and parsing of the message simpler to do. message-length = 1*DIGIT S Shanmugham IETF-Draft Page 18 MRCPv2 Protocol February, 2005 The request-id field is a unique identifier representable as a unsigned 32 bit integer created by the client and sent to the server. The initial value of the request-id is arbitrary. Consecutive requests within a MRCP session MUST contain strictly monotonically increasing and contiguous request-id's. The server resource MUST use this identifier in its response to this request. If the request does not complete with the response future asynchronous events associated with this request MUST carry the request-id. request-id = 1*DIGIT The method-name field identifies the specific request that the client is making to the server. Each resource supports a certain list of requests or methods that can be issued to it, and will be addressed in later sections. method-name = generic-method ; Section 6 / synthesizer-method / recorder-method / recognizer-method / verifier-method 5.2. Response After receiving and interpreting the request message, the server resource responds with an MRCPv2 response message. It consists of a response line followed by message headers and an optional message body containing data specific to the response message. response-line = mrcp-version SP message-length SP request-id SP status-code SP request-state CRLF The mrcp-version field used here MUST be the same as the one used in the Request Line and specifies the version of the MRCPv2 protocol running on the server. The request-id used in the response MUST match the one sent in the corresponding request message. The status-code field is a 3-digit code representing the success or failure or other status of the request. The request-state field indicates if the job initiated by the Request is PENDING, IN-PROGRESS or COMPLETE. The COMPLETE status means that the Request was processed to completion and that there are will be no more events from that resource to the client with that request-id. The PENDING status means that the job has been placed on a queue and will be processed in first-in-first-out order. The IN-PROGRESS status means that the request is being processed and S Shanmugham IETF-Draft Page 19 MRCPv2 Protocol February, 2005 is not yet complete. A PENDING or IN-PROGRESS status indicates that further Event messages will be delivered with that request-id. request-state = "COMPLETE" / "IN-PROGRESS" / "PENDING" Status Codes The status codes are classified under the Success (2XX) codes, Client Failure(4XX) codes, Server Failure (5XX), and Reserved (9xx). Success 2xx 200 Success 201 Success with some optional headers ignored. Client Failure 4xx 401 Method not allowed 402 Method not valid in this state 403 Unsupported Header 404 Illegal Value for Header 405 Resource not allocated for this session or doesn't exist 406 Mandatory Header Missing 407 Method or Operation Failed(e.g. Grammar compilation failed in the recognizer. Detailed cause codes MAY BE available through a resource specific header field.) 408 Unrecognized or unsupported message entity 409 Unsupported Header Value 421-499 Resource specific Failure codes Server Failure 5xx 501 Server Internal Error 502 Protocol Version not supported 503 Proxy Timeout. The MRCP Proxy did not receive a response from the MRCP server. 504 Message too large. Reserved 9xx 900-999 Reserved for experimental use. 5.3. Event The server resource may need to communicate a change in state or the occurrence of a certain event to the client. These messages are used when a request does not complete immediately and the response S Shanmugham IETF-Draft Page 20 MRCPv2 Protocol February, 2005 returns a status of PENDING or IN-PROGRESS. The intermediate results and events of the request are indicated to the client through the event message from the server. The event message consists of an event header line followed by message headers and an optional message body containing data specific to the event message. The header line has the request-id of the request that is in progress and generating these events and status value. The status value is COMPLETE if the request is done and this was the last event, else it is IN-PROGRESS. event-line = mrcp-version SP message-length SP event-name SP request-id SP request-state CRLF The mrcp-version used here is identical to the one used in the Request/Response Line and indicates the version of MRCPv2 protocol running on the server. The request-id used in the event MUST match the one sent in the request that caused this event. The request-state indicates if the Request/Command causing this event is complete or still in progress, and is the same as the one mentioned in section 5.3. The final event will contain a COMPLETE status indicating the completion of the request. The event-name identifies the nature of the event generated by the media resource. The set of valid event names are dependent on the resource generating it, and will be addressed in later sections. event-name = synthesizer-event / recognizer-event / recorder-event / verifier-event 6. MRCP Generic Features The protocol supports a set of methods, and headers that are common to all resources and are discussed in this section generic-method = "SET-PARAMS" / "GET-PARAMS" 6.1. Generic Message Headers MRCPv2 header fields, which include generic-header (section 6.1) and resource-header (section 8.4 and section 9.4), follow the same generic format as that given in Section 3.1 of RFC 822 [8]. Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive. The field value MAY be preceded by any amount of LWS, though a single SP is preferred. S Shanmugham IETF-Draft Page 21 MRCPv2 Protocol February, 2005 Header fields can be extended over multiple lines by preceding each extra line with at least one SP or HT. message-header = field-name ":" [ field-value ] field-name = token field-value = *LWS field-content *( CRLF 1*LWS field-content) field-content = <the OCTETs making up the field-value and consisting of either *TEXT or combinations of token, separators, and quoted-string> The field-content does not include any leading or trailing LWS: linear white space occurring before the first non-whitespace character of the field-value or after the last non-whitespace character of the field-value. Such leading or trailing LWS MAY be removed without changing the semantics of the field value. Any LWS that occurs between field-content MAY be replaced with a single SP before interpreting the field value or forwarding the message downstream. The order in which header fields with differing field names are received is not significant. However, it is "good practice" to send general-header fields first, followed by request-header or response- header fields, and ending with the entity-header fields. Multiple message-header fields with the same field-name MAY be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [i.e., #(values)]. It MUST be possible to combine the multiple header fields into one "field-name: field-value" pair, without changing the semantics of the message, by appending each subsequent field-value to the first, each separated by a comma. The order in which header fields with the same field-name are received is therefore significant to the interpretation of the combined field value, and thus a proxy MUST NOT change the order of these field values when a message is forwarded. generic-header = channel-identifier / active-request-id-list / proxy-sync-id / content-id / content-type / content-length / content-base / content-location / content-encoding / cache-control / logging-tag / set-cookie / set-cookie2 / vendor-specific S Shanmugham IETF-Draft Page 22 MRCPv2 Protocol February, 2005 Header field where s g A __________________________________________________________ Channel-Identifier R m m m Channel-Identifier r m m m Active-Request-Id-List R - - o Active-Request-Id-List r - - o Proxy-Sync-Id R - - o Content-Id R o o o Content-Type R o o o Content-Length R o o o Content-Base R o o o Content-Location R o o o Content-Encoding R o o o Cache-Control R o o o Logging-Tag R o o - Set-Cookie R o o o Set-Cookie2 R o o o Vendor-Specific R o o o Legend: (s) - SET-PARAMS, (g) - GET-PARAMS, (A) - Generic MRCP message, (o) - Optional to use, but mandatory to implement, (R) - Request, (m) - Mandatory, (r) - Response. (For all optional header fields please refer text for further constraints and usage) All headers in MRCPv2 will be case insensitive consistent with HTTP and SIP protocol header definitions. Channel-Identifier All MRCPv2 methods, responses and events MUST contain the Channel- Identifier header field. The value of this field is a hexadecimal string and is allocated by the server when the control channel was added to the session through a SDP offer/answer exchange. This field consists of 2 parts separated by the '@' symbol. The first part is a 32 bit hexadecimal integer that is positive, identifying the MRCP session. The second part is a string token which specifies one of the media processing resource types listed in Section 3.2. The hexadecimal digit string MUST BE unique within the server and is common to all resource channels established through a single SIP session. channel-identifier = "Channel-Identifier" ":" channel-id CRLF Channel-id = 1*HEXDIG "@" 1*VCHAR Active-Request-Id-List In a request, this field indicates the list of request-ids that the request should apply to. This is useful when there are multiple S Shanmugham IETF-Draft Page 23 MRCPv2 Protocol February, 2005 Requests that are PENDING or IN-PROGRESS and you want this request to apply to one or more of these specifically. In a response, this field returns the list of request-ids that the operation modified or affected. There could be one or more requests that returned a request-state of PENDING or IN-PROGRESS. When a method affecting one or more PENDING or IN-PROGRESS requests is sent from the client to the server, the response MUST contain the list of request-ids that were affected or modified by this command in its header field. The active-request-id-list is only used in requests and responses, not in events. For example, if a STOP request with no active-request-id-list is sent to a synthesizer resource(a wildcard STOP) which has one or more SPEAK requests in the PENDING or IN-PROGRESS state, all SPEAK requests MUST be cancelled, including the one IN-PROGRESS and the response to the STOP request would contain the request-id of all the SPEAK requests that were terminated in the active-request-id-list. In this case, no SPEAK-COMPLETE or RECOGNITION-COMPLETE events will be sent for these terminated requests. active-request-id-list = "Active-Request-Id-List" ":" request-id *("," request-id) CRLF Proxy-Sync-Id When any server resource generates a barge-in-able event, it will generate a unique Tag and send it as a header field in an event to the client. The client then acts as a proxy to the server resource and sends a BARGE-IN-OCCURRED method to the synthesizer server resource with the Proxy-Sync-Id it received from the server resource. When the recognizer and synthesizer resources are part of the same session, they may choose to work together to achieve quicker interaction and response. Here the proxy-sync-id helps the resource receiving the event, proxied by the client, to decide if this event has been processed through a direct interaction of the resources. proxy-sync-id = "Proxy-Sync-Id" ":" 1*VCHAR CRLF Accept-Charset See [H14.2]. This specifies the acceptable character set for entities returned in the response or events associated with this request. This is useful in specifying the character set to use in the NLSML results of a RECOGNITION-COMPLETE event. Content-Type S Shanmugham IETF-Draft Page 24 MRCPv2 Protocol February, 2005 See [H14.17]. Note that the content types suitable for MRCPv2 are restricted to speech markup, grammar, recognition results etc. and are specified later in this document. The multi-part content type "multi-part/mixed" is supported to communicate multiple of the above mentioned contents, in which case the body parts cannot contain any MRCPv2 specific headers. Content-Id This field contains an ID or name for the content, by which it can be referred to. The definition of this field is in full compliance with RFC 2392 [15] and is needed in multi-part messages. In MRCPv2 whenever the content needs to be stored, by either the client or the server, it is stored associated with this ID. Such content can be referenced during the session in URI form using the session: URI scheme described in a later section. Content-Base The content-base entity-header field may be used to specify the base URI for resolving relative URLs within the entity. content-base = "Content-Base" ":" absoluteURI CRLF Note, however, that the base URI of the contents within the entity- body may be redefined within that entity-body. An example of this would be a multi-part MIME entity, which in turn can have multiple entities within it. Content-Encoding The content-encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional content coding have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain the media- type referenced by the content-type header field. Content-encoding is primarily used to allow a document to be compressed without losing the identity of its underlying media type. content-encoding = "Content-Encoding" ":" *WSP content-coding *(*WSP "," *WSP content-coding *WSP ) CRLF Content coding is defined in [H3.5]. An example of its use is Content-Encoding: gzip If multiple encoding have been applied to an entity, the content coding MUST be listed in the order in which they were applied. S Shanmugham IETF-Draft Page 25 MRCPv2 Protocol February, 2005 Content-Location The content-location entity-header field MAY BE used to supply the resource location for the entity enclosed in the message when that entity is accessible from a location separate from the requested resource's URI. Refer [H14.14] content-location = "Content-Location" ":" ( absoluteURI / relativeURI ) CRLF The content-location value is a statement of the location of the resource corresponding to this particular entity at the time of the request. The server MAY use this header field to optimize certain operations. When providing this header field the entity being sent should not have been modified, from what was retrieved from the content-location URI. For example, if the client provided a grammar markup inline, and it had previously retrieved it from a certain URI, that URI can be provided as part of the entity, using the content-location header field. This allows a resource like the recognizer to look into its cache to see if this grammar was previously retrieved, compiled and cached. In which case, it might optimize by using the previously compiled grammar object. If the content-location is a relative URI, the relative URI is interpreted relative to the content-base URI. Content-Length This field contains the length of the content of the message body (i.e. after the double CRLF following the last header field). Unlike HTTP, it MUST be included in all messages that carry content beyond the header portion of the message. If it is missing, a default value of zero is assumed. It is interpreted according to [H14.13]. Cache-Control If the server plans on implementing caching it MUST adhere to the cache correctness rules of HTTP 1.1 (RFC2616), when accessing and caching HTTP URI. In particular, the expires and cache-control headers of the cached URI or document must be honored and will always take precedence over the Cache-Control defaults set by this header field. The cache-control directives are used to define the default caching algorithms on the server for the session or request. The scope of the directive is based on the method it is sent on. If the directives are sent on a SET-PARAMS method, it MUST apply for all requests for external documents the server makes during that session. If the directives are sent on any other messages they MUST only apply to external document requests the server makes for that S Shanmugham IETF-Draft Page 26 MRCPv2 Protocol February, 2005 method. An empty cache-control header on the GET-PARAMS method is a request for the server to return the current cache-control directives setting on the server. cache-control = "Cache-Control" ":" cache-directive *("," *LWS cache-directive) CRLF cache-directive = "max-age" "=" delta-seconds / "max-stale" [ "=" delta-seconds ] / "min-fresh" "=" delta-seconds delta-seconds = 1*DIGIT Here delta-seconds is a decimal time value to be specified as the number of seconds from the time that the message response or data was received by the server. These directives allow the server to override the basic expiration mechanism. max-age Indicates that the client is ok with the server using a response whose age is no greater than the specified time in seconds. Unless a max-stale directive is also included, the client is not willing to accept the media server using a stale response. min-fresh Indicates that the client is willing to accept the server using a response whose freshness lifetime is no less than its current age plus the specified time in seconds. That is, the client wants the server to use a response that will still be fresh for at least the specified number of seconds. max-stale Indicates that the client is willing to accept the server using a response or data that has exceeded its expiration time. If max-stale is assigned a value, then the client is willing to accept the server using a response that has exceeded its expiration time by no more than the specified number of seconds. If no value is assigned to max-stale, then the client is willing to accept the server using a stale response of any age. The server cache MAY BE requested to use stale response/data without validation, but only if this does not conflict with any "MUST"-level requirements concerning cache validation (e.g., a "must-revalidate" cache-control directive) in the HTTP 1.1 specification pertaining the URI. S Shanmugham IETF-Draft Page 27 MRCPv2 Protocol February, 2005 If both the MRCPv2 cache-control directive and the cached entry on the server include "max-age" directives, then the lesser of the two values is used for determining the freshness of the cached entry for that request. Logging-Tag This header field MAY BE sent as part of a SET-PARAMS/GET-PARAMS method to set the logging tag for logs generated by the server. Once set, the value persists until a new value is set or the session is ended. The MRCPv2 server SHOULD provide a mechanism to subset its output logs so that system administrators can examine or extract only the log file portion during which the logging tag was set to a certain value. MRCPv2 clients using this feature SHOULD take care to ensure that no two clients specify the same logging tag. In the event that two clients specify the same logging tag, the effect on the MRCPv2 server's output logs in undefined. logging-tag = "Logging-Tag" ":" 1*VCHAR CRLF Set-Cookie and Set-Cookie2: Since the HTTP client on the MRCP server fetches documents for processing on behalf of the MRCP client, the cookie store in the HTTP client of the MRCP server is considered to be an extension of the cookie store in the HTTP client of the MRCP client. This requires that the MRCP client and server be able to synchronize their cookie stores as needed. The MRCP client should be able to push its stored cookies to the MRCP server and get new cookies that the MRCPv2 server stored back to the MRCP client. The set-cookie and set-cookie2 entity-header fields MAY BE included in MRCPv2 requests to update the cookie store on a server and be returned in final MRCPv2 responses or events to subsequently update the client's own cookie store. The stored cookies on the server persist for the duration of the MRCPv2 session and MUST be destroyed at the end of the session. Since the type of cookie header is dictated by the HTTP origin server, MRCPv2 clients and servers SHOULD support both the set-cookie and set-cookie2 entity header fields. set-cookie = "Set-Cookie:" cookies CRLF cookies = cookie *("," *LWS cookie) cookie = attribute "=" value *(";" cookie-av) cookie-av = "Comment" "=" value / "Domain" "=" value / "Max-Age" "=" value / "Path" "=" value / "Secure" / "Version" "=" 1*DIGIT S Shanmugham IETF-Draft Page 28 MRCPv2 Protocol February, 2005 / "Age" "=" delta-seconds set-cookie2 = "Set-Cookie2:" cookies2 CRLF cookies2 = cookie2 *("," *LWS cookie2) cookie2 = attribute "=" value *(";" cookie-av2) cookie-av2 = "Comment" "=" value / "CommentURL" "=" <"> http_URL <"> / "Discard" / "Domain" "=" value / "Max-Age" "=" value / "Path" "=" value / "Port" [ "=" <"> portlist <"> ] / "Secure" / "Version" "=" 1*DIGIT / "Age" "=" delta-seconds portlist = portnum *("," *LWS portnum) portnum = 1*DIGIT The set-cookie and set-cookie2 header fields are specified in RFC 2109 and RFC 2965 respectively. The "Age" attribute is introduced in this specification to indicate the age of the cookie and is OPTIONAL. An MRCPv2 client or server SHOULD calculate the age of the cookie according to the age calculation rules in the HTTP/1.1 specification (RFC 2616) and append the "Age" attribute accordingly. The media client or server MUST supply defaults for the Domain and Path attributes if omitted by the HTTP origin server as specified in RFC 2109 (set-cookie) and RFC 2965 (set-cookie2). Note that there will be no leading dot present in the Domain attribute value in this case. Although an explicitly specified Domain value received via the HTTP protocol may be modified to include a leading dot, a media client or server MUST NOT modify the Domain value when received via the MRCPv2 protocol. A media client or server MAY combine multiple cookie header fields of the same type into a single "field-name: field-value" pair as described in Section 6.1. The set-cookie and set-cookie2 headers MAY BE specified in any request that subsequently results in the server performing an HTTP access. When a server receives new cookie information from an HTTP origin server, and assuming the cookie store is modified according to RFC 2109 or RFC2965, the server MUST return the new cookie information in the MRCPv2 COMPLETE response or event as appropriate to allow the client to update its own cookie store. The SET-PARAMS request MAY specify the set-cookie and set-cookie2 headers to update the cookie store on a server. The GET-PARAMs request MAY BE used to return the entire cookie store of "Set- Cookie" or "Set-Cookie2" type cookies to the client. S Shanmugham IETF-Draft Page 29 MRCPv2 Protocol February, 2005 Vendor Specific Parameters This set of headers allows for the client to set Vendor Specific parameters. vendor-specific = "Vendor-Specific-Parameters" ":" vendor-specific-av-pair *[";" vendor-specific-av-pair] CRLF vendor-specific-av-pair = vendor-av-pair-name "=" vendor-av-pair-value This header MAY BE sent in the SET-PARAMS/GET-PARAMS method and is used to set vendor-specific parameters on the server side. The vendor-av-pair-name follows the reverse Internet Domain Name convention (see section 13 for syntax and registration information). The vendor-av-pair-value is the value to set the attribute to and needs to be quoted. Example: com.cisco.paramxyz:256 com.cisco.paramabc:High com.nuance.paramxyz:Low When asking the server to get the current value of these parameters, this header can be sent in the GET-PARAMS method with the list of vendor-specific attribute names to get separated by a semicolon. 6.2. SET-PARAMS The SET-PARAMS method, from the client to server, tells the MRCP resource to define session parameters, like voice characteristics and prosody on synthesizers or recognition timers on recognizers etc. If the server accepted and set all parameters it MUST return a Response-Status of 200. If it chose to ignore some optional headers that can be safely ignored with affecting operation of the server it MUST return 201. If some of the headers being set are unsupported for the resource or have illegal values, the server MUST reject the request with a 403, Bad Parameter, and MUST include in the response the header fields that could not be set. The header specified in SET-PARAMS affect the session level values. They do not apply for request level scope and for request that are in-PROGRESS. Example: C->S:MRCP/2.0 124 SET-PARAMS 543256 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: female Voice-category: adult Voice-variant: 3 S Shanmugham IETF-Draft Page 30 MRCPv2 Protocol February, 2005 S->C:MRCP/2.0 47 543256 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth 6.3. GET-PARAMS The GET-PARAMS method, from the client to server, asks the MRCPv2 resource for its current session parameters, like voice characteristics and prosody on synthesizers and recognition-timer on recognizers etc. The client SHOULD send the list of parameters it wants to read from the server by listing a set of empty header fields. If a specific list is not specified then the server SHOULD return all the settable headers including vendor-specific parameters and their current values. The wild card use can be very intensive as the number of settable parameters can be large depending on the vendor. Hence it is RECOMMENDED that the client does not use the wildcard GET-PARAMS operation very often. Note that the GET-PARAMS returns header values that have been set for the whol session and do not return values that have a request level scope. Example: C->S:MRCP/2.0 136 GET-PARAMS 543256 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: Voice-category: Voice-variant: Vendor-Specific-Parameters:com.mycorp.param1; com.mycorp.param2 S->C:MRCP/2.0 163 543256 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Voice-gender:female Voice-category: adult Voice-variant: 3 Vendor-Specific-Parameters:com.mycorp.param1="Company Name"; com.mycorp.param2="124324234@mycorp.com" 7. Resource Discovery The list and capability of media resources on a server can be found using the SIP OPTIONS method requesting the capability of the server. The server SHOULD respond to such a request with an SDP description of its capabilities according to RFC 3264. The MRCPv2 capabilities are described by a single m-line containing the media type "application", transport type "TCP/TLS/MRCPv2", "TCP/MRCPv2". There should be one "resource" attribute for each media resource that the server supports with the resource type identifier as its value. S Shanmugham IETF-Draft Page 31 MRCPv2 Protocol February, 2005 The SDP description MUST also contain m-lines describing the audio capabilities, and the coders it supports. Example 4: The client uses the SIP OPTIONS method to query the capabilities of the MRCPv2 server. C->S: OPTIONS sip:mrcp@mediaserver.com SIP/2.0 Max-Forwards: 6 To: <sip:mrcp@mediaserver.com> From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 63104 OPTIONS Contact: <sip:sarvi@cisco.com> Accept: application/sdp Content-Length: 0 S->C: SIP/2.0 200 OK To: <sip:mrcp@mediaserver.com>;tag=93810874 From: Sarvi <sip:sarvi@Cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 63104 OPTIONS Contact: <sip:mrcp@mediaserver.com> Allow: INVITE, ACK, CANCEL, OPTIONS, BYE Accept: application/sdp Accept-Encoding: gzip Accept-Language: en Supported: foo Content-Type: application/sdp Content-Length: 274 v=0 o=sarvi 2890844526 2890842807 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 m=application 9 TCP/MRCPv2 a=resource:speechsynth a=resource:speechrecog a=resource:speakverify m=audio 0 RTP/AVP 0 1 3 a=rtpmap:0 PCMU/8000 a=rtpmap:1 1016/8000 a=rtpmap:3 GSM/8000 S Shanmugham IETF-Draft Page 32 MRCPv2 Protocol February, 2005 8. Speech Synthesizer Resource This resource is capable of converting text provided by the client and generating a speech stream in real-time. Depending on the implementation and capability of this resource, the client can control parameters like voice characteristics, speaker speed, etc. The synthesizer resource is controlled by MRCPv2 requests from the client. Similarly the resource can respond to these requests or generate asynchronous events to the server to indicate certain conditions during the processing of the stream. This section applies for the following resource types. 1. speechsynth 2. basicsynth The capability of these resources are addressed in Section 4.5. 8.1. Synthesizer State Machine The synthesizer maintains states to correlate MRCPv2 requests from the client. The state transitions shown below describe the states of the synthesizer and reflect the request at the head of the queue. A SPEAK request in the PENDING state can be deleted or stopped by a STOP request and does not affect the state of the resource. Idle Speaking Paused State State State | | | |----------SPEAK------->| |--------| |<------STOP------------| CONTROL | |<----SPEAK-COMPLETE----| |------->| |<----BARGE-IN-OCCURRED-| | | |--------| | | CONTROL |-----------PAUSE--------->| | |------->|<----------RESUME---------| | | |----------| | | PAUSE | | | |--------->| | |----------| | | | SPEECH-MARKER | | |<---------| | |----------| | |------------| | STOP | SPEAK | | | | |----------->| |<---------| | | |<--------------------STOP-------------------------| |----------| | | | LOAD-LEXICON | | S Shanmugham IETF-Draft Page 33 MRCPv2 Protocol February, 2005 | | | | |<---------| | | |<--------------------BARGE-IN-OCCURRED------------| 8.2. Synthesizer Methods The synthesizer supports the following methods. synthesizer-method = "SPEAK" ; A / "STOP" ; B / "PAUSE" ; C / "RESUME" ; D / "BARGE-IN-OCCURRED" ; E / "CONTROL" ; F / "LOAD-LEXICON" ; G 8.3. Synthesizer Events The synthesizer may generate the following events. synthesizer-event = "SPEECH-MARKER" ; H / "SPEAK-COMPLETE" ; I 8.4. Synthesizer Header Fields A synthesizer message may contain header fields containing request options and information to augment the Request, Response or Event the message it is associated with. synthesizer-header = jump-size / kill-on-barge-in / speaker-profile / completion-cause / completion-reason / voice-parameter / prosody-parameter / speech-marker / speech-language / fetch-hint / audio-fetch-hint / fetch-timeout / failed-uri / failed-uri-cause / speak-restart / speak-length / load-lexicon / lexicon-search-order Header field where s g A B C D E F G H I __________________________________________________________ Jump-Size R - - - - - - - o - - - S Shanmugham IETF-Draft Page 34 MRCPv2 Protocol February, 2005 Kill-On-Barge-In R - - o - - - - - - - - Speaker-Profile R o o o - - - - o - - - Completion-Cause R - - - - - - - - - - m Completion-Cause 4XX - - o - - - - - - - - Completion-Reason R - - - - - - - - - - m Completion-Reason 4XX - - o - - - - - - - - Voice-Parameter R o o o - - - - o - - - Prosody-Parameter R o o o - - - - o - - - Speech-Marker R - - - - - - - - - m m Speech-Marker 2XX - - m m m m - m - - - Speech-Language R o o o - - - - - - - - Fetch-Hint R o o o - - - - - - - - Audio-Fetch-Hint R o o o - - - - - - - - Fetch-Timeout R o o o - - - - - - - - Failed-URI R - - - - - - - - - - o Failed-URI 4XX - o - - - - - - - - o Failed-URI-Cause R - - - - - - - - - - o Failed-URI-Cause 4XX - o - - - - - - - - o Speak-Restart 2XX - - - - - - - o - - - Speak-Length R - o - - - - - o - - - Load-Lexicon R - - - - - - - - o - - Lexicon-Search-Order R - - - - - - - - m - - Legend: (s) - SET-PARAMS, (g) - GET-PARAMS, (A) - SPEAK, (B) - STOP, (C) - PAUSE, (D) RESUME, (E) - BARGE-IN-OCCURRED, (F) - CONTROL, (G) - LOAD-LEXICON (o) - Optional(Refer text for further constraints), (m) - Mandatory, (R) - Request, (r) - Response Jump-Size This header MAY BE specified in a CONTROL method and controls the jump size to move forward or rewind backward on an active SPEAK request. A + or - indicates a relative value to what is being currently played. This MAY BE specified in a SPEAK request to indicate an offset into the speech markup that the SPEAK request should start speaking from. The different speech length units supported are dependent on the synthesizer implementation. If it does not support a unit or the operation the resource SHOULD respond with a status code of 404 "Illegal or Unsupported value for parameter". jump-size = "Jump-Size" ":" speech-length-value CRLF speech-length-value = numeric-speech-length / text-speech-length text-speech-length = 1*VCHAR SP "Tag" numeric-speech-length= ("+" / "-") 1*DIGIT SP numeric-speech-unit numeric-speech-unit = "Second" / "Word" / "Sentence" S Shanmugham IETF-Draft Page 35 MRCPv2 Protocol February, 2005 / "Paragraph" Kill-On-Barge-In This header MAY BE sent as part of the SPEAK method to enable kill- on-barge-in support. If enabled, the SPEAK method is interrupted by DTMF input detected by a signal detector resource or by the start of speech sensed or recognized by the speech recognizer resource. kill-on-barge-in = "Kill-On-Barge-In" ":" boolean-value CRLF boolean-value = "true" / "false" If the recognizer or signal detector resource is on the same server as the synthesizer, the server SHOULD recognize their interactions by their common MRCPv2 channel identifier (ignoring the portion after "@" which is the resource type) and work with each other to provide kill-on-barge-in support. The client MUST send a BARGE-IN-OCCURRED method to the synthesizer resource when it receives a bargin-in-able event from any source. This source could be a synthesizer resource or signal detector resource and MAY BE local or distributed. If this field is not specified, the value defaults to "true". Speaker Profile This header MAY BE part of the SET-PARAMS/GET-PARAMS or SPEAK request from the client to the server and specifies the profile of the speaker by a uri, which may be a set of voice parameters like gender, accent etc. speaker-profile = "Speaker-Profile" ":" uri CRLF Completion Cause This header field MUST be specified in a SPEAK-COMPLETE event coming from the synthesizer resource to the client. This indicates the reason behind the SPEAK request completion. completion-cause = "Completion-Cause" ":" 1*DIGIT SP 1*VCHAR CRLF Cause-Code Cause-Name Description 000 normal SPEAK completed normally. 001 barge-in SPEAK request was terminated because of barge-in. 002 parse-failure SPEAK request terminated because of a failure to parse the speech markup text. 003 uri-failure SPEAK request terminated because, access to one of the URIs failed. 004 error SPEAK request terminated prematurely due S Shanmugham IETF-Draft Page 36 MRCPv2 Protocol February, 2005 to synthesizer error. 005 language-unsupported Language not supported. 006 lexicon-load-failure Lexicon loading failed. Completion Reason This header field MAY be specified in a SPEAK-COMPLETE event coming from the synthesizer resource to the client. This contains the reason text behind the SPEAK request completion. This field can be use to communicate text describing the reason for the failure, such as an error in parsing the speech markup text. completion-reason = "Completion-Reason" ":" quoted-string CRLF Voice-Parameters This set of headers defines the voice of the speaker. voice-parameter = "Voice-" voice-param-name ":" voice-param-value CRLF voice-param-name is any one of the attribute names under the voice element specified in W3C's Speech Synthesis Markup Language Specification[10]. The voice-param-value is any one of the value choices of the corresponding voice element attribute specified in the above section. These header fields MAY BE sent in SET-PARAMS/GET-PARAMS request to define/get default values for the entire session or MAY BE sent in the SPEAK request to define default values for that speak request. Furthermore these attributes can be part of the speech text marked up in SML. These voice parameter header fields can also be sent in a CONTROL method to affect a SPEAK request in progress and change its behavior on the fly. If the synthesizer resource does not support this operation, it should respond back to the client with a status of unsupported. Prosody-Parameters This set of headers defines the prosody of the speech. prosody-parameter = "Prosody-" prosody-param-name ":" prosody-param-value CRLF S Shanmugham IETF-Draft Page 37 MRCPv2 Protocol February, 2005 prosody-param-name is any one of the attribute names under the prosody element specified in W3C's Speech Synthesis Markup Language Specification[10]. The prosody-param-value is any one of the value choices of the corresponding prosody element attribute specified in the above section. These header fields MAY BE sent in SET-PARAMS/GET-PARAMS request to define/get default values for the entire session or MAY BE sent in the SPEAK request to define default values for that speak request. Further more these attributes can be part of the speech text marked up in SML. The prosody parameter header fields in the SET-PARAMS or SPEAK request only apply if the speech data is of type text/plain and does not use a speech markup format. These prosody parameter header fields MAY also be sent in a CONTROL method to affect a SPEAK request in progress and change its behavior on the fly. If the synthesizer resource does not support this operation, it should respond back to the client with a status of unsupported. Speech Marker This header field contains a marker tag that may be embedded in the speech data. Most speech markup formats provide mechanisms to embed marker fields between speech texts. The synthesizer will generate SPEECH-MARKER events when it reaches these marker fields. This field SHOULD be part of the SPEECH-MARKER event and will contain the marker tag values. This header may have additional timestamp information in a "timestamp" field separated by a semicolon. This is the NTP timestamp and MUST be synced with the RTP timestamp. This header field SHOULD also be returned in responses to STOP and CONTROL methods and in the SPEAK-COMPLETE event. In these messages the marker tag SHOULD be the last tag encountered and would be "" if none was encountered. The marker tag SHOULD have timestamp information which reflects at what point into the current SPEAK request the particular message was generated. timestamp = "timestamp" "=" time-stamp-value CRLF speech-marker = "Speech-Marker" ":" 1*VCHAR [";" timestamp ]CRLF Speech Language This header field specifies the default language of the speech data if it is not specified in it. The value of this header field should follow RFC 3066 for its values. This MAY occur in SPEAK, SET-PARAMS or GET-PARAMS requests. S Shanmugham IETF-Draft Page 38 MRCPv2 Protocol February, 2005 speech-language = "Speech-Language" ":" 1*VCHAR CRLF Fetch Hint When the synthesizer needs to fetch documents or other resources like speech markup or audio files, etc., this header field controls URI access properties. This defines when the synthesizer should retrieve content from the server. A value of "prefetch" indicates a file may be downloaded when the request is received, whereas "safe" indicates a file that should only be downloaded when actually needed. The default value is "prefetch". This header field MAY occur in SPEAK, SET-PARAMS or GET-PARAMS requests. fetch-hint = "Fetch-Hint" ":" 1*ALPHA CRLF Audio Fetch Hint When the synthesizer needs to fetch documents or other resources like speech audio files, etc., this header field controls URI access properties. This defines whether or not the synthesizer can attempt to optimize speech by pre-fetching audio. The value is either "safe" to say that audio is only fetched when it is needed, never before; "prefetch" to permit, but not require the platform to pre-fetch the audio; or "stream" to allow it to stream the audio fetches. The default value is "prefetch". This header field MAY occur in SPEAK, SET-PARAMS or GET-PARAMS. requests. audio-fetch-hint = "Audio-Fetch-Hint" ":" 1*ALPHA CRLF Fetch Timeout When the synthesizer needs to fetch documents or other resources like speech audio files, etc., this header field controls URI access properties. This defines the synthesizer timeout for content the server may need to fetch from the network. This is specified in milliseconds. The default value is platform-dependent. This header field MAY occur in SPEAK, SET-PARAMS or GET-PARAMS. fetch-timeout = "Fetch-Timeout" ":" 1*DIGIT CRLF Failed URI When a synthesizer method needs a synthesizer to fetch or access a URI and the access fails the server SHOULD provide the failed URI in this header field in the method response. failed-uri = "Failed-URI" ":" Uri CRLF Failed URI Cause S Shanmugham IETF-Draft Page 39 MRCPv2 Protocol February, 2005 When a synthesizer method needs a synthesizer to fetch or access a URI and the access fails the server SHOULD provide the URI specific or protocol specific response code through this header field in the method response. This field has been defined as alphanumeric to accommodate all protocols, some of which might have a response string instead of a numeric response code. failed-uri-cause = "Failed-URI-Cause" ":" 1*alphanum CRLF Speak Restart When a CONTROL request to jump backward is issued to a currently speaking synthesizer resource and the target jump point is beyond the start of the current SPEAK request, the current SPEAK request SHALL re-start from the beginning of its speech data and the response to the CONTROL request SHOULD contain this header indicating a restart. This header MAY occur in the CONTROL response. speak-restart = "Speak-Restart" ":" boolean-value CRLF Speak Length This header MAY be specified in a CONTROL method to control the length of speech to speak, relative to the current speaking point in the currently active SPEAK request. A - value is illegal in this field. If a field with a Tag unit is specified, then the media must speak till the tag is reached or the SPEAK request complete, whichever comes first. This MAY BE specified in a SPEAK request to indicate the length to speak in the speech data and is relative to the point in speech the SPEAK request starts. The different speech length units supported are dependent on the synthesizer implementation. If it does not support a unit or the operation the resource SHOULD respond with a status code of 404 "Illegal or Unsupported value for header". speak-length = "Speak-Length" ":" speech-length-value CRLF speech-length-value = numeric-speech-length / text-speech-length text-speech-length = 1*VCHAR SP "Tag" numeric-speech-length= ("+" / "-") 1*DIGIT SP numeric-speech-unit numeric-speech-unit = "Second" / "Word" / "Sentence" / "Paragraph" Load-Lexicon This header field is used to indicate whether a lexicon has to be loaded or unloaded. The default value for this field is "true". S Shanmugham IETF-Draft Page 40 MRCPv2 Protocol February, 2005 load-lexicon = "Load-Lexicon" : Boolean-value CRLF Lexicon-Search-Order This header field is used to specify the list of active Lexicon URIs and the search order among the active lexicons. Note, the lexicons specified within the SSML document still takes precedence over the lexicons specified here. Lexicon-search-order = "Lexicon-Search-Order" : uri-list CRLF 8.5. Synthesizer Message Body A synthesizer message may contain additional information associated with the Method, Response or Event in its message body. Synthesizer Speech Data Marked-up text for the synthesizer to speak is specified as a MIME entity in the message body. The message to be spoken by the synthesizer can be specified inline by embedding the data in the message body or by reference by providing the URI to the data. In either case the data and the format used to markup the speech needs to be supported by the server. All MRCPv2 servers MUST support plain text speech data and W3C's Speech Synthesis Markup Language[10] as a minimum and hence MUST support the MIME types text/plain and application/ssml+xml at a minimum. If the speech data needs to be specified by URI reference the MIME type text/uri-list is used to specify the one or more URI that will list what needs to be spoken. If a list of speech URI is specified, speech data provided by each URI must be spoken in the order in which the URI are specified. If the data to be spoken consists of a mix of URI and inline speech data the multipart/mixed MIME-type is used and embedded with the MIME-blocks for text/uri-list, application/ssml+xml or text/plain. The character set and encoding used in the speech data may be specified according to standard MIME-type definitions. The multi- part MIME-block can contain actual audio data in .wav or sun audio format. This is used when the client has audio clips that it may have recorded and has it stored in memory or a local device and it needs to play it as part of the SPEAK request. The audio MIME-parts, can be sent by the client as part of the multi-part MIME-block. This audio will be referenced in the speech markup data that will be S Shanmugham IETF-Draft Page 41 MRCPv2 Protocol February, 2005 another part in the multi-part MIME-block according to the multipart/mixed MIME-type specification. Example 1: Content-Type: text/uri-list Content-Length: 176 http://www.example.com/ASR-Introduction.ssml http://www.example.com/ASR-Document-Part1.ssml http://www.example.com/ASR-Document-Part2.ssml http://www.example.com/ASR-Conclusion.ssml Example 2: Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> Example 3: Content-Type: multipart/mixed; boundary="break" --break Content-Type: text/uri-list Content-Length: 176 http://www.example.com/ASR-Introduction.ssml http://www.example.com/ASR-Document-Part1.ssml http://www.example.com/ASR-Document-Part2.ssml http://www.example.com/ASR-Conclusion.ssml --break Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> S Shanmugham IETF-Draft Page 42 MRCPv2 Protocol February, 2005 <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> --break-- Lexicon Data Synthesizer lexicon data from the client to the server can be provided inline or by reference. Either way they are carried as MIME entities in the message body of the MRCPv2 request message. When a lexicon is specified in-line in the message, the client MUST provide a content-id for that lexicon as part of the content headers. The server MUST store the lexicon associated with that content-id for the duration of the session. A stored lexicon can be overwritten by defining a new lexicon with the same content-id. Lexicons that have been associated with a content-id can be referenced through a special "session:" URI scheme. If lexicon data needs to be specified by external URI reference, the MIME-type text/uri-list is used to list the one or more URI that will specify the lexicon data. All media servers MUST support the HTTP uri access mechanism. If the data to be defined consists of a mix of URI and inline lexicon data the multipart/mixed MIME-type is used. The character set and encoding used in the lexicon data may be specified according to standard MIME-type definitions. 8.6. SPEAK The SPEAK method from the client to the server provides the synthesizer resource with the speech text and initiates speech synthesis and streaming. The SPEAK method can carry voice and prosody header fields that define the behavior of the voice being synthesized, as well as the actual marked-up text to be spoken. If specific voice and prosody parameters are specified as part of the S Shanmugham IETF-Draft Page 43 MRCPv2 Protocol February, 2005 speech markup text, it will take precedence over the values specified in the header fields and those set using a previous SET- PARAMS request. When applying voice parameters there are 3 levels of scope. The highest precedence are those specified within the speech markup text, followed by those specified in the header fields of the SPEAK request and hence apply for that SPEAK request only, followed by the session default values which can be set using the SET-PARAMS request and apply for the whole session moving forward. If the resource is idle and the SPEAK request is being actively processed the resource will respond with a success status code and a request-state of IN-PROGRESS. If the resource is in the speaking or paused states, i.e. it is in the middle of processing a previous SPEAK request, the status returns success and a request-state of PENDING. This means that this SPEAK request will be placed in the request queue and will be processed in the other order received after the currently active SPEAK request and previously queued SPEAK requests are completed. For the synthesizer resource, this is the only request that can return a request-state of IN-PROGRESS or PENDING. When the text to be synthesized is complete, the resource will issue a SPEAK-COMPLETE event with the request-id of the SPEAK message and a request-state of COMPLETE. Example: C->S:MRCP/2.0 489 SPEAK 543257 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> S Shanmugham IETF-Draft Page 44 MRCPv2 Protocol February, 2005 </p> </speak> S->C:MRCP/2.0 28 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 79 SPEAK-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Completion-Cause: 000 normal 8.7. STOP The STOP method from the client to the server tells the resource to stop speaking if it is speaking something. The STOP request can be sent with an active-request-id-list header field to stop the zero or more specific SPEAK requests that may be in queue and return a response code of 200(Success). If no active- request-id-list header field is sent in the STOP request it will terminate all outstanding SPEAK requests. If a STOP request successfully terminated one or more PENDING or IN- PROGRESS SPEAK requests, then the response message body contains an active-request-id-list header field listing the SPEAK request-ids that were terminated. Otherwise there will be no active-request-id- list header field in the response. No SPEAK-COMPLETE events will be sent for these terminated requests. If a SPEAK request that was IN-PROGRESS and speaking was stopped the next pending SPEAK request, if any, would become IN-PROGRESS and move to the speaking state. If a SPEAK request that was IN-PROGRESS and in the paused state was stopped the next pending SPEAK request, if any, would become IN- PROGRESS and move to the paused state. Example: C->S:MRCP/2.0 423 SPEAK 543258 Channel-Identifier: 32AECB23433802@speechsynth Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" S Shanmugham IETF-Draft Page 45 MRCPv2 Protocol February, 2005 xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 48 543258 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth C->S:MRCP/2.0 44 STOP 543259 200 Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 66 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 8.8. BARGE-IN-OCCURRED The BARGE-IN-OCCURRED method is a mechanism for the client to communicate a barge-in-able event it detects to the speech resource. This event is useful in two scenarios, 1. The client has detected some events like DTMF digits or other barge-in-able events and wants to communicate that to the synthesizer. 2. The recognizer resource and the synthesizer resource are in different servers. In which case the client MUST act as a proxy and receive event from the recognition resource, and then send a BARGE- IN-OCCURRED method to the synthesizer. In such cases, the BARGE-IN- OCCURRED method would also have a proxy-sync-id header field received from the resource generating the original event. If a SPEAK request is active with kill-on-barge-in enabled, and the BARGE-IN-OCCURRED event is received, the synthesizer should stop streaming out audio. It should also terminate any speech requests queued behind the current active one, irrespective of whether they have barge-in enabled or not. If a barge-in-able prompt was playing and it was terminated, the response MUST contain the request-ids of all SPEAK requests that were terminated in its active-request-id- list. There will be no SPEAK-COMPLETE events generated for these requests. S Shanmugham IETF-Draft Page 46 MRCPv2 Protocol February, 2005 If the synthesizer and the recognizer are part of the same session they could be optimized for a quicker kill-on-barge-in response by the recognizer and synthesizer interacting directly. In these cases, the client MUST still proxy the START-OF-SPEECH event through a BARGE-IN-OCCURRED method, but the synthesizer resource may have already stopped and sent a SPEAK-COMPLETE event with a barge in completion cause code. If there were no SPEAK requests terminated as a result of the BARGE-IN-OCCURRED method, the response would still be a 200 success but MUST NOT contain an active-request-id- list header field. C->S:MRCP/2.0 433 SPEAK 543258 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 47 543258 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth C->S:MRCP/2.0 69 BARGE-IN-OCCURRED 543259 200 Channel-Identifier: 32AECB23433802@speechsynth Proxy-Sync-Id: 987654321 S->C:MRCP/2.0 72 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 8.9. PAUSE S Shanmugham IETF-Draft Page 47 MRCPv2 Protocol February, 2005 The PAUSE method from the client to the server tells the resource to pause speech, if it is speaking something. If a PAUSE method is issued on a session when a SPEAK is not active the server SHOULD respond with a status of 402 or "Method not valid in this state". If a PAUSE method is issued on a session when a SPEAK is active and paused the server SHOULD respond with a status of 200 or "Success". If a SPEAK request was active the server MUST return an active- request-id-list header with the request-id of the SPEAK request that was paused. C->S:MRCP/2.0 434 SPEAK 543258 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 48 543258 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth C->S:MRCP/2.0 43 PAUSE 543259 Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 68 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 8.10. RESUME The RESUME method from the client to the server tells a paused synthesizer resource to continue speaking. If a RESUME method is issued on a session with no active SPEAK request, the server SHOULD S Shanmugham IETF-Draft Page 48 MRCPv2 Protocol February, 2005 respond with a status of 402 or "Method not valid in this state". If a RESUME method is issued on a session with an active SPEAK request is speaking(i.e. not paused) the server SHOULD respond with a status of 200 or "Success". If a SPEAK request was active the server MUST return an active-request-id-list header with the request-id of the SPEAK request that was resumed Example: C->S:MRCP/2.0 434 SPEAK 543258 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 48 543258 200 IN-PROGRESS@speechsynth Channel-Identifier: 32AECB23433802 C->S:MRCP/2.0 44 PAUSE 543259 Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 47 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 C->S:MRCP/2.0 44 RESUME 543260 Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 66 543260 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 S Shanmugham IETF-Draft Page 49 MRCPv2 Protocol February, 2005 8.11. CONTROL The CONTROL method from the client to the server tells a synthesizer that is speaking to modify what it is speaking on the fly. This method is used to make the synthesizer jump forward or backward in what it is speaking, change speaker rate, and speaker parameters, etc. It affects the active or IN-PROGRESS SPEAK request. Depending on the implementation and capability of the synthesizer resource it may allow this operation or one or more of its headers. When a CONTROL to jump forward is issued and the operation goes beyond the end of the active SPEAK method's text, the CONTROL request succeeds. Also, the active SPEAK request completes and returns a SPEAK-COMPLETE event following the response to the CONTROL method. If there are more SPEAK requests in the queue, the synthesizer resource will start at the beginning of the next SPEAK request in the queue. When a CONTROL to jump backwards is issued and the operation jumps to the beginning or beyond the beginning of the speech data of the active SPEAK request, the response to the CONTROL request contains the speak-restart header, and the active SPEAK request starts from the beginning of its speech data. These two behaviors can be used to rewind or fast-forward across multiple speech requests, if the client wants to break up a speech markup text to multiple SPEAK requests. If a SPEAK request was active when the CONTROL method was received the server MUST return an active-request-id-list header with the Request-id of the SPEAK request that was active. Example: C->S:MRCP/2.0 434 SPEAK 543258 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams S Shanmugham IETF-Draft Page 50 MRCPv2 Protocol February, 2005 and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 47 543258 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth C->S:MRCP/2.0 63 CONTROL 543259 Channel-Identifier: 32AECB23433802@speechsynth Prosody-rate: fast S->C:MRCP/2.0 67 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 C->S:MRCP/2.0 68 CONTROL 543260 Channel-Identifier: 32AECB23433802@speechsynth Jump-Size: -15 Words S->C:MRCP/2.0 69 543260 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 8.12. SPEAK-COMPLETE This is an Event message from the synthesizer resource to the client indicating that the SPEAK request was completed. The request-id header field WILL match the request-id of the SPEAK request that initiated the speech that just completed. The request-state field should be COMPLETE indicating that this is the last Event with that request-id, and that the request with that request-id is now complete. The completion-cause header field specifies the cause code pertaining to the status and reason of request completion such as the SPEAK completed normally or because of an error or kill-on- barge-in etc. Example: C->S:MRCP/2.0 434 SPEAK 543260 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> S Shanmugham IETF-Draft Page 51 MRCPv2 Protocol February, 2005 <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C:MRCP/2.0 48 543260 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 73 SPEAK-COMPLETE 543260 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Completion-Cause: 000 normal 8.13. SPEECH-MARKER This is an event generated by the synthesizer resource to the client when it hits a marker tag in the speech markup it is currently processing. The request-id field in the header matches the SPEAK request request-id that initiated the speech. The request-state field should be IN-PROGRESS as the speech is still not complete and there is more to be spoken. The actual speech marker tag hit, describing where the synthesizer is in the speech markup, is returned in the speech-marker header field, with an NTP timestamp. The SPEECH-MARKER event is also generated with a marker value of "" and the NTP timestamp, when a SPEAK-REQUEST in Pending-State(in the queue) moves to IN-PROGRESS and starts speaking. The NTP timestamp MUST be synchronized with the RTP timestamp used to generate the speech stream. Example: C->S:MRCP/2.0 434 SPEAK 543261 Channel-Identifier: 32AECB23433802@speechsynth Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: synthesis+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" S Shanmugham IETF-Draft Page 52 MRCPv2 Protocol February, 2005 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <mark name="here"/> <s>The subject is <prosody rate="-20%">ski trip</prosody> </s> <mark name="ANSWER"/> </p> </speak> S->C:MRCP/2.0 48 543261 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth S->C:MRCP/2.0 73 SPEECH-MARKER 543261 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth Speech-Marker: here S->C:MRCP/2.0 74 SPEECH-MARKER 543261 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth Speech-Marker: ANSWER S->C:MRCP/2.0 73 SPEAK-COMPLETE 543261 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Completion-Cause: 000 normal 8.14. DEFINE-LEXICON The DEFINE-LEXICON method, from the client to the server, provides a lexicon and tells the server to load, unload, activate or deactivate the lexicon. If the server resource is in the speaking or paused state, the DEFINE-LEXICON request MUST respond with a failure status. If the resource is in the idle state and is able to successfully load/unload/activate/deactivate the lexicon the status MUST return a success code and the request-state MUST be COMPLETE. If the synthesizer could not define the lexicon for some reason, say the download failed or the lexicon was in an unsupported form, the MRCPv2 response for the DEFINE-LEXICON method MUST contain a failure status code of 407, and a completion-cause header field describing the failure reason. S Shanmugham IETF-Draft Page 53 MRCPv2 Protocol February, 2005 9. Speech Recognizer Resource The speech recognizer resource is capable of receiving an incoming voice stream and providing the client with an interpretation of what was spoken in textual form. This section applies for the following resource types. 1. speechrecog 2. dtmfrecog The difference between the above two resources is in their level of support for recognition grammars. The "dtmfrecog" resource is capable of recognizing DTMF digits only and hence will accept DTMF grammars only. The "speechrecog" can recognize regular speech as well as DTMF digits and hence SHOULD support grammars describing speech or DTMF. The recognition resource may support recognition in the normal or hotword modes or both. For implementations where a single recognition resource does not support both modes, they can be implemented as separate resources and allocated to the same SIP session with different MRCP session identifiers and share the RTP audio feed. Normal Mode Recognition Regular mode recognition tries to match all of the speech or dtmf from the time it starts recognizing to the grammar and returns a no- match status if it fails to match or times out. Hotword Mode Recognition Hotword mode is where the recognizer looks for a specific speech grammar or dtmf sequence and ignores speech or DTMF that does not match. It does not timeout nor generate a no-match and will complete only for a successful match of grammar. Voice Enrolled Grammars A recognition resource may optionally support Voice Enrolled Grammars. With this functionality enrollment is performed using a person's voice. For example, a list of contacts can be created and maintained by recording the person's names using the caller's voice. This technique is sometimes also called speaker-dependent recognition. Voice Enrollment has a concept of an enrollment session. A session to add a new phrase to a personal grammar involves the initial enrollment followed by a repeat of enough utterances before committing the new phrase to the personal grammar. Each time an utterance is recorded, it is compared for similarity with the other samples and a clash test is performed against other entries in the S Shanmugham IETF-Draft Page 54 MRCPv2 Protocol February, 2005 personal grammar to ensure there are no similar and confusable entries. Enrollment is done using a Recognizer resource. Controlling which utterances are to be considered for enrollment of a new phrase is done by setting a header field in the Recognize request. 9.1. Recognizer State Machine The recognizer resource is controlled by MRCPv2 requests from the client. Similarly the resource can respond to these requests or generate asynchronous events to the server to indicate certain conditions during the processing of the stream. Hence the recognizer maintains states to correlate MRCPv2 requests from the client. The state transitions are described below. Idle Recognizing Recognized State State State | | | |---------RECOGNIZE---->|---RECOGNITION-COMPLETE-->| |<------STOP------------|<-----RECOGNIZE-----------| | | | | | |-----------| | |--------| GET-RESULT | | START-OF-SPEECH | |---------->| |------------| |------->| | | | |----------| | | DEFINE-GRAMMAR | START-INPUT-TIMERS | |<-----------| |<---------| | | | | | |------| | |-------| | RECOGNIZE | | STOP |<-----| | |<------| | | | |<-------------------STOP--------------------------| |<-------------------DEFINE-GRAMMAR----------------| If a recognition resource support voice enrolled grammars, starting an enrollment session does not change the state of the recognizer resource. Once an enrollment session is started, then utterances are enrolled by calling the RECOGNIZE method repeatedly. The state of the Speech Recognizer resources goes from IDLE to RECOGNIZING state each time RECOGNIZE is called. 9.2. Recognizer Methods The recognizer supports the following methods. recognizer-method = recog-only-method S Shanmugham IETF-Draft Page 55 MRCPv2 Protocol February, 2005 / enrollment-method recog-only-method = "DEFINE-GRAMMAR" ; A / "RECOGNIZE" ; B / "INTERPRET" ; C / "GET-RESULT" ; D / "START-INPUT-TIMERS" ; E / "STOP" ; F It is OPTIONAL for a recognizer resource to support voice enrolled grammars. If the recognizer resource does support voice enrolled grammars it MUST support the following methods. enrollment-method = "START-PHRASE-ENROLLMENT" ; G / "ENROLLMENT-ROLLBACK" ; H / "END-PHRASE-ENROLLMENT" ; I / "MODIFY-PHRASE" ; J / "DELETE-PHRASE" ; K 9.3. Recognizer Events The recognizer may generate the following events. recognizer-event = "START-OF-SPEECH" ; L / "RECOGNITION-COMPLETE" ; M / "INTERPRETATION-COMPLETE" ; N 9.4. Recognizer Header Fields A recognizer message may contain header fields containing request options and information to augment the Method, Response or Event message it is associated with. recognizer-header = recog-only-header / enrollment-header recog-only-header = confidence-threshold / sensitivity-level / speed-vs-accuracy / n-best-list-length / no-input-timeout / recognition-timeout / waveform-uri / input-waveform-uri / completion-cause / completion-reason / recognizer-context-block / start-input-timers / speech-complete-timeout / speech-incomplete-timeout / dtmf-interdigit-timeout S Shanmugham IETF-Draft Page 56 MRCPv2 Protocol February, 2005 / dtmf-term-timeout / dtmf-term-char / fetch-timeout / failed-uri / failed-uri-cause / save-waveform / new-audio-channel / speech-language / ver-buffer-utterance / recognition-mode / cancel-if-queue / hotword-max-duration / hotword-min-duration / interpret-text / one-of-rule-id-uri If a recognition resource supports voice enrolled grammars, the following header fields apply towards using that functionality. enrollment-header = num-min-consistent-pronunciations / consistency-threshold / clash-threshold / personal-grammar-uri / phrase-id / phrase-nl / weight / save-best-waveform / new-phrase-id / confusable-phrases-uri / abort-phrase-enrollment Header field where s g A B C D E F G H I J K L M N __________________________________________________________ Confidence-Threshold R o o - o - o - - - - - - - - - - Sensitivity-Level R o o - o - - - - - - - - - - - - Speed-Vs-Accuracy R o o - o - - - - - - - - - - - - N-Best-List-Length R o o - o - o - - - - - - - - - - No-Input-Timeout R o o - o - - - - - - - - - - - - Recognition-Timeout R o o - o - - - - - - - - - - - - Waveform-URI R - - - - - - - - - - - - - - o - Waveform-URI 2XX - - - - - - - - - - o - - - - - Input-Waveform-URI R - - - o - - - - - - - - - - - - Completion-Cause R - - - - - - - - - - - - - - m m Completion-Cause 2XX - - o o o - - - - - - - - - - - Completion-Cause 4XX - - m m m - - - - - - - - - - - Completion-Reason R - - - - - - - - - - - - - - m m Completion-Reason 2XX - - o o o - - - - - - - - - - - Completion-Reason 4XX - - m m m - - - - - - - - - - - Recognizer-Context-Bl. R o o - - - - - - - - - - - - - - Start-Input-Timers R - - - o - - - - - - - - - - - - Speech-Complete-Time. R o o - o - - - - - - - - - - - - S Shanmugham IETF-Draft Page 57 MRCPv2 Protocol February, 2005 Speech-Incomplete-Time. R o o - o - - - - - - - - - - - - DTMF-Interdigit-Timeo. R o o - o - - - - - - - - - - - - DTMF-Term-Timeout R o o - o - - - - - - - - - - - - DTMF-Term-Char R o o - o - - - - - - - - - - - - Fetch-Timeout R o o o o - - - - - - - - - - - - Failed-URI R - - - - - - - - - - - - - - o o Failed-URI 4XX - - o o - - - - - - - - - - - - Failed-URI-Cause R - - - - - - - - - - - - - - o o Failed-URI-Cause 4XX - - o o - - - - - - - - - - - - Save-Waveform R o o - o - - - - - - - - - - - - New-Audio-Channel R - - - o - - - - - - - - - - - - Speech-Language R o o o o - - - - - - - - - - - - Ver-Buffer-Utterance R o o - o - - - - - - - - - - - - Recognition-Mode R - - - o - - - - - - - - - - - - Cancel-If-Queue R - - - o - - - - - - - - - - - - Hotword-Max-Duration R o o - o - - - - - - - - - - - - Hotword-Min-Duration R o o - o - - - - - - - - - - - - Interpret-Text R - - - - m - - - - - - - - - - - One-Of-Rule-Id-URI R - - - o o - - - - - - - - - - - Num-Min-Consistent-Pr R o o - - - - - - o - - - - - - - Consistency-Threshold R o o - - - - - - o - - - - - - - Clash-Threshold R o o - - - - - - o - - - - - - - Personal-Grammar-URI R o o - - - - - - o - - o o - - - Phrase-ID R - - - - - - - - m - - m m - - - Phrase-NL R - - - - - - - - o - - o - - - - Weight R - - - - - - - - o - - o - - - - Save-Best-Waveform R o o - - - - - - o - - - - - - - New-Phrase-ID R - - - - - - - - - - - o - - - - Confusable-Phrases-URI R - - - o - - - - - - - - - - - - Abort-Phrase-Enrollment R - - - - - - - - - - o - - - - - Legend: (s) - SET-PARAMS, (g) - GET-PARAMS, (A) - DEFINE, (B) - RECOGNIZE, (C) -INTERPRET, (D) GET-RESULT, (E) - START-INPUT-TIMERS, (F) - STOP, (G) - START-PHRASE-ENROLLMENT, (H) - ENROLLMENT- ROLLBACK, (I) - END-PHRASE-ENROLLMENT, (J) - MODIFY-PHRASE, (K) - DELETE-PHRASE, (L) - START-OF-SPEECH, (M) - RECOGNITION-COMPLETE, (N) - INTERPRETATION-COMPLETE (o) - Optional(Refer text for further constraints), (m) - Mandatory, (R) - Request, (r) - Response For enrollment-specific header fields that can appear as part of SET-PARAMS or GET-PARAMS methods, the following general rule applies: the START-PHRASE-ENROLLMENT method must be called before these header fields can be set through the SET-PARAMS method or retrieved through the GET-PARAMS method. Note that the waveform-uri header field of the Recognizer resource can also appear in the response to the END-PHRASE-ENROLLMENT method. S Shanmugham IETF-Draft Page 58 MRCPv2 Protocol February, 2005 Confidence Threshold When a recognition resource recognizes or matches a spoken phrase with some portion of the grammar, it associates a confidence level with that conclusion. The confidence-threshold header tells the recognizer resource what confidence level should be considered a successful match. This is a float value between 0.0-1.0 indicating the recognizer's confidence in the recognition. If the recognizer determines that its confidence in all its recognition results is less than the confidence threshold, then it MUST return no-match as the recognition result. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. The default value for this field is platform specific. confidence-threshold= "Confidence-Threshold" ":" FLOAT CRLF Sensitivity Level To filter out background noise and not mistake it for speech, the recognizer may support a variable level of sound sensitivity. The sensitivity-level header is a float value between 0.0 and 1.0 and allows the client to set the sensity level for the recognizer. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. A higher value for this field means higher sensitivity. The default value for this field is platform specific. sensitivity-level = "Sensitivity-Level" ":" FLOAT CRLF Speed Vs Accuracy Depending on the implementation and capability of the recognizer resource it may be tunable towards Performance or Accuracy. Higher accuracy may mean more processing and higher CPU utilization, meaning less calls per server and vice versa. This header is a float value between 0.0 and 1.0 and allows this field to be tuned by the speed-vs-accuracy header. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. A higher value for this field means higher speed. The default value for this field is platform specific. speed-vs-accuracy = "Speed-Vs-Accuracy" ":" FLOAT CRLF N Best List Length When the recognizer matches an incoming stream with the grammar, it may come up with more than one alternative matches because of confidence levels in certain words or conversation paths. If this header field is not specified, by default, the recognition resource will only return the best match above the confidence threshold. The client, by setting this header, could ask the recognition resource to send it more than 1 alternative. All alternatives must still be above the confidence-threshold. A value greater than one does not S Shanmugham IETF-Draft Page 59 MRCPv2 Protocol February, 2005 guarantee that the recognizer will send the requested number of alternatives. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. The minimum value for this field is 1. The default value for this field is 1. n-best-list-length = "N-Best-List-Length" ":" 1*DIGIT CRLF No Input Timeout When recognition is started and there is no speech detected for a certain period of time, the recognizer can send a RECOGNITION- COMPLETE event to the client and terminate the recognition operation. The no-input-timeout header field can set this timeout value. The value is in milliseconds. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. no-input-timeout = "No-Input-Timeout" ":" 1*DIGIT CRLF Recognition Timeout When recognition is started and there is no match for a certain period of time, the recognizer can send a RECOGNITION-COMPLETE event to the client and terminate the recognition operation. It is the timer that is started when START-OF-SPEECH event is generated by the resource and specifies the maximum duration of the utterance. When this timer expires the recognition request would complete with a status code of "008 too-much-speech-timeout". The recognition- timeout header field sets this timeout value. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value is 10 seconds. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. recognition-timeout = "Recognition-Timeout" ":" 1*DIGIT CRLF Waveform URI If the save-waveform header field is set to true, the recognizer MUST record the incoming audio stream of the recognition into a file and provide a URI for the client to access it. This header MUST be present in the RECOGNITION-COMPLETE event if the save-waveform header field was set to true. The URI value of the header MUST be NULL if there was some error condition preventing the server from recording. Otherwise, the URI generated by the server SHOULD be globally unique across the server and all its recognition sessions. The URI SHOULD BE available until the session is torn down. S Shanmugham IETF-Draft Page 60 MRCPv2 Protocol February, 2005 Similarly, if the save-best-waveform header field is set to true, the recognizer MUST save the audio stream for the best repetition of the phrase that was used during the enrollment session. The recognizer MUST then record the recognized audio and make it available to the client in the form of a URI returned in the waveform-uri header field in the response to the END-PHRASE- ENROLLMENT method. The URI value of the header MUST be NULL if there was some error condition preventing the server from recording. Otherwise, the URI generated by the server SHOULD be globally unique across the server and all its recognition sessions. The URI SHOULD BE available until the session is torn down. waveform-uri = "Waveform-URI" ":" Uri CRLF Input-Waveform-Uri This optional header field specifies an audio file that has to be processed according to the RECOGNIZE operation. This enables the client to recognize from a specified buffer or audio file. It MAY be part of the RECOGNIZE method. input-waveform-uri = "Input-Waveform-URI" ":" Uri CRLF Completion Cause This header field MUST be part of a RECOGNITION-COMPLETE, event coming from the recognizer resource to the client. This indicates the reason behind the RECOGNIZE method completion. This header field MUST BE sent in the DEFINE-GRAMMAR and RECOGNIZE responses, if they return with a failure status and a COMPLETE state. completion-cause = "Completion-Cause" ":" 1*DIGIT SP 1*VCHAR CRLF Cause-Code Cause-Name Description 000 success RECOGNIZE completed with a match or DEFINE-GRAMMAR succeeded in downloading and compiling the grammar 001 no-match RECOGNIZE completed, but no match was found 002 no-input-timeout RECOGNIZE completed without a match due to a no-input-timeout 003 recognition-timeout RECOGNIZE completed without a match due to a recognition-timeout 004 gram-load-failure RECOGNIZE failed due grammar load failure. S Shanmugham IETF-Draft Page 61 MRCPv2 Protocol February, 2005 005 gram-comp-failure RECOGNIZE failed due to grammar compilation failure. 006 error RECOGNIZE request terminated prematurely due to a recognizer error. 007 speech-too-early RECOGNIZE request terminated because speech was too early. This happens when the audio stream is already "in-speech" when the RECOGNIZE request was received. 008 too-much-speech-timeout RECOGNIZE request terminated because speech was too long. 009 uri-failure Failure accessing a URI. 010 language-unsupported Language not supported. 011 cancelled A new RECOGNIZE cancelled this one. 012 semantics-failure Recognition succeeded but semantic interpretation of the recognized input failed. The RECOGNITION- COMPLETE event MUST contain the Recognition result with only input text and no interpretation. Completion Reason This header field MAY be specified in a RECOGNITION-COMPLETE event coming from the recognizer resource to the client. This contains the reason text behind the RECOGNIZE request completion. This field can be use to communicate text describing the reason for the failure, such as an error in parsing the grammar markup text. completion-reason = "Completion-Reason" ":" quoted-string CRLF Recognizer Context Block This header MAY BE sent as part of the SET-PARAMS or GET-PARAMS request. If the GET-PARAMS method contains this header field with no value, then it is a request to the recognizer to return the recognizer context block. The response to such a message MAY contain a recognizer context block as a message entity. If the server returns a recognizer context block, the response MUST contain this header field and its value MUST match the content-id of that entity. If the SET-PARAMS method contains this header field, it MUST contain a message entity containing the recognizer context data, and a content-id matching this header field. This content-id should match S Shanmugham IETF-Draft Page 62 MRCPv2 Protocol February, 2005 the content-id that came with the context data during the GET-PARAMS operation. Each recognition vendor choosing to use this mechanism to handoff recognizer context data between servers MUST distinguish its vendor specific block of data by using an IANA-registered content type in the IANA MIME vendor tree. recognizer-context-block = "Recognizer-Context-Block" ":" 1*VCHAR CRLF Start Input Timers This header MAY BE sent as part of the RECOGNIZE request. A value of false tells the recognizer to start recognition, but not to start the no-input timer yet. The recognizer should not start the timers until the client sends a START-INPUT-TIMERS request to the recognizer. This is useful in the scenario when the recognizer and synthesizer engines are not part of the same session. Here when a kill-on-barge-in prompt is being played, you want the RECOGNIZE request to be simultaneously active so that it can detect and implement kill-on-barge-in. But at the same time you don't want the recognizer to start the no-input timers until the prompt is finished. The default value is "true". start-input-timers = "Start-Input-Timers" ":" boolean-value CRLF Speech Complete Timeout This header field specifies the length of silence required following user speech before the speech recognizer finalizes a result (either accepting it or throwing a nomatch event). The speech-complete- timeout value is used when the recognizer currently has a complete match of an active grammar, and specifies how long it should wait for more input declaring a match. By contrast, the incomplete timeout is used when the speech is an incomplete match to an active grammar. The value is in milliseconds. speech-complete-timeout= "Speech-Complete-Timeout" ":" 1*DIGIT CRLF A long speech-complete-timeout value delays the result completion and therefore makes the computer's response slow. A short speech- complete-timeout may lead to an utterance being broken up inappropriately. Reasonable complete timeout values are typically in the range of 0.3 seconds to 1.0 seconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. S Shanmugham IETF-Draft Page 63 MRCPv2 Protocol February, 2005 Speech Incomplete Timeout This header field specifies the required length of silence following user speech after which a recognizer finalizes a result. The incomplete timeout applies when the speech prior to the silence is an incomplete match of all active grammars. In this case, once the timeout is triggered, the partial result is rejected (with a nomatch event). The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. speech-incomplete-timeout= "Speech-Incomplete-Timeout" ":" 1*DIGIT CRLF The speech-incomplete-timeout also applies when the speech prior to the silence is a complete match of an active grammar, but where it is possible to speak further and still match the grammar. By contrast, the complete timeout is used when the speech is a complete match to an active grammar and no further words can be spoken. A long speech-incomplete-timeout value delays the result completion and therefore makes the computer's response slow. A short speech- incomplete-timeout may lead to an utterance being broken up inappropriately. The speech-incomplete-timeout is usually longer than the speech- complete-timeout to allow users to pause mid-utterance (for example, to breathe). This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. DTMF Interdigit Timeout This header field specifies the inter-digit timeout value to use when recognizing DTMF input. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value is 5 seconds. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. dtmf-interdigit-timeout= "DTMF-Interdigit-Timeout" ":" 1*DIGIT CRLF DTMF Term Timeout This header field specifies the terminating timeout to use when recognizing DTMF input. The DTMF-Term-Timeout applies only when no additional input is allowed by the grammar; otherwise, the DTMF-Interdigit-Timeout applies. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value is 10 seconds. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. S Shanmugham IETF-Draft Page 64 MRCPv2 Protocol February, 2005 dtmf-term-timeout = "DTMF-Term-Timeout" ":" 1*DIGIT CRLF DTMF-Term-Char This header field specifies the terminating DTMF character for DTMF input recognition. The default value is NULL which is specified as an empty header field. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. dtmf-term-char = "DTMF-Term-Char" ":" VCHAR CRLF Fetch Timeout When the recognizer needs to fetch grammar documents this header field controls URI access properties. This defines the recognizer timeout for content that the server may need to fetch from the network. The value is in milliseconds. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. This header field MAY occur in RECOGNIZE, SET-PARAMS or GET-PARAMS. fetch-timeout = "Fetch-Timeout" ":" 1*ALPHA CRLF Failed URI When a recognizer method needs a recognizer to fetch or access a URI and the access fails the server SHOULD provide the failed URI in this header field in the method response. failed-uri = "Failed-URI" ":" Uri CRLF Failed URI Cause When a recognizer method needs a recognizer to fetch or access a URI and the access fails the server SHOULD provide the URI specific or protocol specific response code through this header field in the method response. This field has been defined as alphanumeric to accommodate all protocols, some of which might have a response string instead of a numeric response code. failed-uri-cause = "Failed-URI-Cause" ":" 1*alphanum CRLF Save Waveform This header field allows the client to indicate to the recognizer that it MUST save the audio stream that was recognized. The recognizer MUST then record the recognized audio, without end- pointing and make it available to the client in the form of a URI returned in the waveform-uri header field in the RECOGNITION- S Shanmugham IETF-Draft Page 65 MRCPv2 Protocol February, 2005 COMPLETE event. If there was an error in recording the stream or the audio clip is otherwise not available, the recognizer MUST return an empty waveform-uri header field. The default value for this fields is "false". save-waveform = "Save-Waveform" ":" boolean-value CRLF New Audio Channel This header field MAY BE specified in a RECOGNIZE message and allows the client to tell the server that, from that point on, it will be sending audio data from a new audio source, channel or speaker. If the recognition resource had collected any line statistics or information, it MUST discard it and start fresh for this RECOGNIZE. Note that if there are multiple resources on the same SIP session that may be collecting or using these line statistics, the client MUST reset the line statistics for all these resource. This helps in the case where the client MAY want to reuse an open recognition session with a media resource for multiple telephone calls. new-audio-channel = "New-Audio-Channel" ":" boolean-value CRLF Speech-Language This header field specifies the language of recognition grammar data within a session or request, if it is not specified within the data. The value of this header field should follow RFC 3066 for its values. This MAY occur in DEFINE-GRAMMAR, RECOGNIZE, SET-PARAMS or GET-PARAMS request. speech-language = "Speech-Language" ":" 1*VCHAR CRLF One-Of-Rule-Id-URI This header field MAY be specified in the RECOGNIZE or INTERPRET method that ONLY carries a single URI or a grammar block in its message body. This header refers to a specific rule-id in the grammar mime-body which should be treated as the list of activation grammars. This rule-id MUST be a <one-of> rule-id and the listed items MUST ALL BE grammar-uri-references and MAY NOT be a grammar token. This is considered equivalent to specifying a tex/uri mime type with a list of grammar URIs for activation, but has the additional benefit of being able to provide weights for the individual grammar URIs. The order of the URI items in the one-of rule-id MUST bet precedence of the list of activation grammars. one-of-rule-id-uri = "One-Of-Rule-Id-URI" ":" token CRLF S Shanmugham IETF-Draft Page 66 MRCPv2 Protocol February, 2005 Ver-Buffer-Utterance This header field is the same as the one described for the Verification resource. This tells the server to buffer the utterance associated with this recognition request into the verification buffer. Sending this header field is not valid if the verification buffer is not instantiated for the session. This buffer is shared across resource within a session and gets instantiated when a verification resource is added to this session and is released when the resource is released from the session. Recognition-Mode This header field specifies what mode the RECOGNIZE command should start up in. The value choices are "normal" or "hotword". If the value is "normal", the RECOGNIZE starts matching all speech and DTMF from that point to the grammars specified in the RECOGNIZE commands. If any portion of the speech does not match the grammar, the RECOGNIZE command completes with a no-match status. Also, timers may be active to detect speech in the audio, and the RECOGNIZE command finish because of timeout waiting for speech. If the value of this header field is "hotword", the RECOGNIZE command starts up in hotword mode, where it only looks for particular keywords or DTMF sequences specified in the grammar and ignore silence or other speech in the audio stream. The default value for this header field is "normal". recognition-mode = "Recognition-Mode" ":" 1*ALPHA CRLF Cancel-If-Queue This header field specifies what should happen to this RECOGNIZE method when the client queues more RECOGNIZE methods to the resource. The value for this header field is Boolean. A value of "true" for this header field in a RECOGNIZE method, means this RECOGNIZE method when active MUST terminate, with a Completion-Cause of "cancelled", when the client queues another RECOGNIZE command to the resource. A value of "false" for this header field in a RECOGNIZE method, means that the RECOGNIZE method will continue till its operation is complete and if the client queues more RECOGNIZE methods to the resource, they are queued. When the current RECOGNIZE method is stopped or completes with a successful match, the first RECOGNIZE method in the queue becomes active. If the current RECOGNIZE fails, all RECOGNIZE methods in the pending queue are cancelled and will generate a RECOGNITION-COMPLETE event with a Completion-Cause of "cancelled". This field MUST exist in all RECOGNIZE methods. cancel-if-queue = "Cancel-If-Queue" ":" Boolean-value CRLF S Shanmugham IETF-Draft Page 67 MRCPv2 Protocol February, 2005 Hotword-Max-Duration This header MAY BE sent in a hotword mode RECOGNIZE request. It specifies the maximum length of an utterance (in seconds) that should be considered for Hotword recognition. This header, along with Hotword-Min-Duration, can be used to tune performance by preventing the recognizer from evaluating utterances that are too short or too long to be the Hotword. The value is in milliseconds. The default is platform dependent. hotword-max-duration = "Hotword-Max-Duration" ":" 1*DIGIT CRLF Hotword-Min-Duration This header MAY BE sent in a hotword mode RECOGNIZE request. It specifies the minimum length of an utterance (in seconds) that can be considered for Hotword. This header, along with Hotword-Max- Duration, can be used to tune performance by preventing the recognizer from evaluating utterances that are too short or too long to be the hot word. The value is in milliseconds. The default value is platform dependent. hotword-min-duration = "Hotword-Min-Duration" ":" 1*DIGIT CRLF Interpret-Text This header field is used to provide the text for which a natural language interpretation is desired. The value of this field has a content-id that refers to a MIME entity of type plain/text in the body of the message. This header field MUST be used when invoking the INTERPRET method. interpret-text = "Interpret-Text" : 1*VCHAR CRLF Num-Min-Consistent-Pronunciations This header MAY BE specified in a START-PHRASE-ENROLLMENT, SET- PARAMS, or GET-PARAMS method and is used to specify the minimum number of consistent pronunciations that must be obtained to voice enroll a new phrase. The minimum value is 1. The default value is platform specific and MAY BE greater than 1. num-min-consistent-pronunciations = "Num-Min-Consistent-Pronunciations" ":" 1*DIGIT CRLF Consistency-Threshold This header MAY BE sent as part of the START-PHRASE-ENROLLMENT, SET- PARAMS, or GET-PARAMS method. Used during voice-enrollment, this S Shanmugham IETF-Draft Page 68 MRCPv2 Protocol February, 2005 header specifies how similar an utterance needs to be, to a previously enrolled pronunciation of the same phrase to be considered "consistent." The higher the threshold, the closer the match between an utterance and previous pronunciations must be for the pronunciation to be considered consistent. The range for this threshold is a float value between is 0.0 to 1.0. The default value for this field is platform specific. consistency-threshold = "Consistency-Threshold" ":" FLOAT CRLF Clash-Threshold This header MAY BE sent as part of the START-PHRASE-ENROLLMENT, SET- PARMS, or GET-PARAMS method. Used during voice-enrollment, this header specifies how similar the pronunciations of two different phrases can be before they are considered to be clashing. For example, pronunciations of phrases such as "John Smith" and "Jon Smits" may be so similar that they are difficult to distinguish correctly. A smaller threshold reduces the number of clashes detected. The range for this threshold is float value between 0.0 and 1.0. The default value for this field is platform specific. clash-threshold = "Clash-Threshold" ":" 1*DIGIT CRLF Personal-Grammar-URI This header specifies the speaker-trained grammar to be used or referenced during enrollment operations. For example, a contact list for user "Jeff" could be stored at the Personal-Grammar- URI="http://myserver/myenrollmentdb/jeff-list". There is no default value for this header field. personal-grammar-uri = "Personal-Grammar-URI" ":" Uri CRLF Phrase-Id This header identifies a phrase in a personal grammar and will also be returned when doing recognition. This header field MAY occur in START-PHRASE-ENROLLMENT, MODIFY-PHRASE or DELETE-PHRASE requests. There is no default value for this header field. phrase-id = "Phrase-ID" ":" 1*VCHAR CRLF Phrase-NL This is a string specifying the natural language statement to execute when the phrase is recognized. This header field MAY occur S Shanmugham IETF-Draft Page 69 MRCPv2 Protocol February, 2005 in START-PHRASE-ENROLLMENT and MODIFY-PHRASE requests. There is no default value for this header field. phrase-nl = "Phrase-NL" ":" 1*VCHAR CRLF Weight The value of this header field represents the occurrence likelihood of this branch of the grammar. The weights are normalized to sum to one at compilation time, so use the value of '1' if you want all branches to have the same weight. This header field MAY occur in START-PHRASE-ENROLLMENT and MODIFY-PHRASE requests. The default value for this field is platform specific. weight = "Weight" ":" weight-value CRLF Save-Best-Waveform This header field allows the client to indicate to the recognizer that it MUST save the audio stream for the best repetition of the phrase that was used during the enrollment session. The recognizer MUST then record the recognized audio and make it available to the client in the form of a URI returned in the waveform-uri header field in the response to the END-PHRASE-ENROLLMENT method. If there was an error in recording the stream or the audio clip is otherwise not available, the recognizer MUST return an empty waveform-uri header field. save-best-waveform = "Save-Best-Waveform" ":" Boolean-value CRLF New-Phrase-Id This header field replaces the id used to identify the phrase in a personal grammar. The recognizer returns the new id when using an enrollment grammar. This header field MAY occur in MODIFY-PHRASE requests. new-phrase-id = "New-Phrase-ID" ":" 1*VCHAR CRLF Confusable-Phrases-URI This optional header field specifies the grammar that defines invalid phrases for enrollment. For example, typical applications do not allow an enrolled phrase that is also a command word. This header field MAY occur in RECOGNIZE requests. confusable-phrases-uri = "Confusable-Phrases-URI" ":" S Shanmugham IETF-Draft Page 70 MRCPv2 Protocol February, 2005 Uri CRLF Abort-Phrase-Enrollment This header field can optionally be specified in the END-PHRASE- ENROLLMENT method to abort the phrase enrollment, rather than committing the phrase to the personal grammar. abort-phrase-enrollment = "Abort-Phrase-Enrollment" ":" Boolean- value CRLF 9.5. Recognizer Message Body A recognizer message may carry additional data associated with the method, response or event. The client may send the grammar to be recognized in DEFINE-GRAMMAR or RECOGNIZE requests. When the grammar is sent in the DEFINE-GRAMMAR method, the server should be able to download compile and optimize the grammar. The RECOGNIZE request MUST contain a list of grammars that need to be active during the recognition. The server resource may send the recognition results in the RECOGNITION-COMPLETE event or the GET-RESULT response. This data will be carried in the message body of the corresponding MRCPv2 message. Recognizer Grammar Data Recognizer grammar data from the client to the server can be provided inline or by reference. Either way they are carried as MIME entities in the message body of the MRCPv2 request message. The grammar specified inline or by reference specifies the grammar used to match in the recognition process and this data is specified in one of the standard grammar specification formats like W3C's XML or ABNF or Sun's Java Speech Grammar Format etc. All MRCPv2 servers MUST support W3C's XML based grammar markup format [11](MIME-type application/srgs+xml) and SHOULD support the ABNF form (MIME-type application/srgs). When a grammar is specified in-line in the message, the client MUST provide a content-id for that grammar as part of the content headers. The server MUST store the grammar associated with that content-id for the duration of the session. A stored grammar can be overwritten by defining a new grammar with the same content-id. Grammars that have been associated with a content-id can be referenced through a special "session:" URI scheme. Example: session:help@root-level.store S Shanmugham IETF-Draft Page 71 MRCPv2 Protocol February, 2005 If grammar data needs to be specified by external URI reference, the MIME-type text/uri-list is used to list the one or more URI that will specify the grammar data. All servers MUST support the HTTP uri access mechanism. If the data to be defined consists of a mix of URI and inline grammar data the multipart/mixed MIME-type is used and embedded with the MIME-blocks for text/uri-list, application/srgs or application/srgs+xml. The character set and encoding used in the grammar data may be specified according to standard MIME-type definitions. When more than one grammar URI or inline grammar block is specified in a message body of the RECOGNIZE request, it is an active list of grammar alternatives to listen. The ordering of the list implies the precedence of the grammars, with the first grammar in the list having the highest precedence. Example 1: Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> <!-- multiple language attachment to a token --> <rule id="people1"> <token lexicon="en-US,fr-CA"> Robert </token> </rule> <!-- the equivalent single-language attachment expansion --> S Shanmugham IETF-Draft Page 72 MRCPv2 Protocol February, 2005 <rule id="people2"> <one-of> <item xml:lang="en-US">Robert</item> <item xml:lang="fr-CA">Robert</item> </one-of> </rule> </grammar> Example 2: Content-Type: text/uri-list Content-Length: 176 session:help@root-level.store http://www.example.com/Directory-Name-List.grxml http://www.example.com/Department-List.grxml http://www.example.com/TAC-Contact-List.grxml session:menu1@menu-level.store Example 3: Content-Type: multipart/mixed; boundary="break" --break Content-Type: text/uri-list Content-Length: 176 http://www.example.com/Directory-Name-List.grxml http://www.example.com/Department-List.grxml http://www.example.com/TAC-Contact-List.grxml --break Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> S Shanmugham IETF-Draft Page 73 MRCPv2 Protocol February, 2005 <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> <!-- multiple language attachment to a token --> <rule id="people1"> <token lexicon="en-US,fr-CA"> Robert </token> </rule> <!-- the equivalent single-language attachment expansion --> <rule id="people2"> <one-of> <item xml:lang="en-US">Robert</item> <item xml:lang="fr-CA">Robert</item> </one-of> </rule> </grammar> --break-- Recognizer Result Data Recognition result data from the server is carried in the MRCPv2 message body of the RECOGNITION-COMPLETE event or the GET-RESULT response message as MIME entities. All servers MUST support Natural Language Semantics Markup Language (NLSML), an XML markup based on an early draft from the W3C. This is the default standard for returning recognition results back to the client, and hence MUST support the MIME-type application/nlsml+xml. MRCP-specific additions to this result format have been made and is fully described in section 9.6 with a normative definition of the DTD and schema in the Appendix. Example 1: Content-Type: application/nlsml+xml Content-Length: 104 <?xml version="1.0"?> <result grammar="http://theYesNoGrammar"> <interpretation> <instance> <response>yes</response> </instance> <input>ok</input> </interpretation> </result> S Shanmugham IETF-Draft Page 74 MRCPv2 Protocol February, 2005 Enrollment Result Data Enrollment results come as part of the RECOGNIZE-COMPLETE event as part of the Recognition result XML data. The XML Schema and DTD for this XML data is provided in section 9.7 with a normative definition of the DTD and scheme in the Appendix. Recognizer Context Block When the client has to change servers within a call, this is a block of data that the client MAY collect from the first server and provide to the second server. This may be because the client needs a different language support or because the server issued a redirect. Here the first recognizer resource may have collected acoustic and other data during its recognition. When we switch servers, communicating this data may allow the recognition resource on the new server to provide better recognition based on the acoustic data collected by the previous recognizer. This block of data is vendor- specific and MUST be carried as MIME-type application/octets in the body of the message. This block of data is communicated in the SET-PARAMS and GET-PARAMS method/response messages. In the GET-PARAMS method, if an empty recognizer-context-block header field is present, then the recognizer should return its vendor-specific context block in the message body as a MIME-entity with a specific content-id. The content-id value should also be specified in the recognizer-context- block header field in the GET-PARAMS response. The SET-PARAMS request wishing to provide this vendor-specific data should send it in the message body as a MIME-entity with the same content-id that it received from the GET-PARAMS. The content-id should also be sent in the recognizer-context-block header field of the SET-PARAMS message. Each automatic speech recognition (ASR) vendor choosing to use this mechanism to handoff recognizer context data among its servers should distinguish its vendor-specific block of data from other vendors by choosing a unique content-id that they should recognize. 9.6. Natural Language Semantic Markup Language The general purpose of the NL Semantics Markup is to represent information automatically extracted from a user's utterances by a semantic interpretation component, where utterance is to be taken in the general sense of a meaningful user input in any modality supported by the platform. A specific architecture can take advantage of this representation by using it to convey content among S Shanmugham IETF-Draft Page 75 MRCPv2 Protocol February, 2005 various system components that generate and make use of the markup. In MRCP it is to be used to convey these results between a recognition resource on the MRCP server and the MRCP client. Components that generate NLSML: 1. Automatic Speech Recognition (ASR) 2. Natural language understanding 3. Other input media interpreters (e.g. DTMF, pointing, keyboard) 4. Reusable dialog components 5. Multimedia integration Components that use NLSML: 1. Dialog manager 2. Multimedia integration A platform may also choose to use this general format as the basis of a general semantic result that is carried along and filled out during each stage of processing. In addition, future systems may also potentially make use of this markup to convey abstract semantic content to be rendered into natural language by a natural language generation component. Markup Functions A semantic interpretation system that supports the Natural Language Semantics Markup Language is responsible for interpreting natural language inputs and formatting the interpretation as defined in this document. Semantic interpretation is typically either included as part of the speech recognition process, or involves one or more additional components, such as natural language interpretation components and dialog interpretation components. The elements of the markup fall into the following general functional categories: Interpretation: Elements and attributes representing the semantics of the user's utterance, including the <result>, <interpretation>, and <instance> elements. The <result> element contains the full result of processing one utterance. It may contain multiple <interpretation> elements if the interpretation of the utterance results in multiple alternative meanings due to uncertainty in speech recognition or natural language understanding. There are at least two reasons for providing multiple interpretations: 1. another component, such as a dialog manager, might have additional information, for example, information from a database, that would allow it to select a preferred S Shanmugham IETF-Draft Page 76 MRCPv2 Protocol February, 2005 interpretation from among the possible interpretations returned from the semantic interpreter. 2. a dialog manager that was unable to select between several competing interpretations could use this information to go back to the user and find out what was intended. For example, Did you say "Boston" or "Austin"? Side Information: Elements and attributes representing additional information about the interpretation, over and above the interpretation itself. Side information includes 1. Whether an interpretation was achieved (the <nomatch> element) and the system's confidence in an interpretation (the "confidence" attribute of <interpretation>). 2. Alternative interpretations (<interpretation>) 3. Input formats and ASR information: The <input> element, representing the input to the semantic interpreter. Multi-modal integration: When more than one modality is available for input, the interpretation of the inputs need to be coordinated. The "mode" attribute of <input> supports this by indicating whether the utterance was input by speech, dtmf, pointing, etc. The"timestamp_start" and "timestamp_end" attributes of <interpretation> also provide for temporal coordination by indicating when inputs occurred. Overview of NLSML Elements and their Relationships The elements in NLSML fall into two categories: 1. description of the input that was processed. 2. description of the meaning which was extracted from the input. Next to each element are its attributes. In addition, some elements can contain multiple instances of other elements. For example, a <result> can contain multiple <interpretations>, each of which is taken to be an alternative. Similarly, <input> can contain multiple child <input> elements which are taken to be cumulative. A URI reference to an XForms data model is permitted but not required. To illustrate the basic usage of these elements, as a simple example, consider the utterance ok (interpreted as "yes"). The S Shanmugham IETF-Draft Page 77 MRCPv2 Protocol February, 2005 example illustrates how that utterance and its interpretation would be represented in the NL Semantics markup. <result grammar="http://theYesNoGrammar> <interpretation> <instance> <response>yes</response> </instance> <input>ok</input> </interpretation> </result> This example includes only the minimum required information. There is an overall <result> element which includes one interpretation, containing the application-specific elements "<yes_no>" and "<response>". Elements and Attributes RESULT Root Element Attributes: grammar, x-model xmlns The root element of the markup is <result>. The <result> element includes one or more <interpretation> elements. Multiple interpretations can result from ambiguities in the input or in the semantic interpretation. If the "grammar" and "x-model" attributes don't apply to all of the interpretations in the result they can be overridden for individual interpretations at the <interpretation> level. Attributes: 1. grammar: The grammar or recognition rule matched by this result. The format of the grammar attribute will match the rule reference semantics defined in the grammar specification. Specifically, the rule reference will be in the external XML form for grammar rule references. The dialog markup interpreter needs to know the grammar rule that is matched by the utterance because multiple rules may be simultaneously active. The value is the grammar URI used by the dialog markup interpreter to specify the grammar. The grammar can be overridden by a grammar attribute in the <interpretation> element if the input was ambiguous as to which grammar it matched. 2. x-model: The URI which defines the XForms data model used for this result. The x-model can be overridden by an x-model attribute in the <interpretation> element if the input was ambiguous as to which x-model it matched.(optional) <result grammar="http://grammar"> S Shanmugham IETF-Draft Page 78 MRCPv2 Protocol February, 2005 <interpretation> .... </interpretation> </result> INTERPRETATION Element Attributes: confidence, grammar, x-model An <interpretation> element contains a single semantic interpretation. Attributes: 1. confidence: An integer from 0-100 indicating the semantic analyzer's confidence in this interpretation. At this point there is no formal, platform-independent, definition of confidence. (optional) 2. grammar: The grammar or recognition rule matched by this interpretation (if needed to override the grammar specification at the <interpretation> level.) This attribute will only be needed under <interpretation> if it is necessary to override a grammar that was defined at the <result> level.) (optional) 3. x-model: The URI which defines the XForms data model used for this interpretation. (As in the case of "grammar", this attribute only needs to be defined under <interpretation> if it is necessary to override the x-model specification at the <interpretation> level.) (optional) Interpretations must be sorted best-first by some measure of "goodness". The goodness measure is "confidence" if present, otherwise, it is some platform-specific indication of quality. The x-model and grammar are expected to be specified most frequently at the <result> level, because most often one data model will be sufficient for the entire result. However, it can be overridden at the <interpretation> level because it is possible that different interpretations may have different data models - perhaps because they match different grammar rules. The <interpretation> element includes an optional <input> element which contains the input being analyzed, and an <instance> element containing the interpretation of the utterance. <interpretation confidence="75" grammar="http://grammar" x-model="http://dataModel"> ... </interpretation> S Shanmugham IETF-Draft Page 79 MRCPv2 Protocol February, 2005 INSTANCE Element The <instance> element contains the interpretation of the utterance. If a reference to a data model is present (that is, if there is an "x-model" attribute on the <result> or <interpretation> elements), the markup describing the instance should conform to that data model. When there is semantic markup in the grammar that does not create semantic objects, but instead only does a semantic translation of a portion of the input, such as translating "coke" to "coca-cola", the instance contains the whole input but with the translation applied. The NLSML looks like in example 2 below. If there is no semantic objects created, nor any semantic translation the instance value is the same as the input value. Attributes: 1. confidence: Each element of the instance may have a confidence attribute, defined in the NL semantics namespace. The confidence attribute contains an integer value in the range from 0-100 reflecting the system's confidence in the analysis of that slot. The meaning of confidence scores has not been defined in a platform-independent way. The default value of "confidence" is 100. (optional) Example 1: <instance name="nameAddress"> <nameAddress> <street confidence="75">123 Maple Street</street> <city>Mill Valley</city> <state>CA</state> <zip>90952</zip> </nameAddress> </instance> <input> My address is 123 Maple Street, Mill Valley, California, 90952 </input> Example 2: <instance> I would like to buy a coca-cola </instance> <input> I would like buy a coke </input> INPUT Element S Shanmugham IETF-Draft Page 80 MRCPv2 Protocol February, 2005 The <input> element is the text representation of a user's input. It includes an optional "confidence" attribute which indicates the recognizer's confidence in the recognition result (as opposed to the confidence in the interpretation, which is indicated by the "confidence" attribute of <interpretation>). Optional "timestamp- start" and "timestamp-end" attributes indicate the start and end times of a spoken utterance, in ISO 8601 format. Attributes: 1. timestamp-start: The time at which the input began. (optional) 2. timestamp-end: The time at which the input ended. (optional) 3. mode: The modality of the input, for example, speech, dtmf, etc. (optional) 4. confidence: the confidence of the recognizer in the correctness of the input in the range 0.0 to 1.0 (optional) Note that it may not make sense for temporally overlapping inputs to have the same mode; however, this constraint is not expected to be enforced by platforms. When there is no time zone designator, ISO 8601 time representations default to local time. There are three possible formats for the <input> element. a) The <input> element can contain simple text: <input>onions</input> A future possibility is for <input> to contain not only text but additional markup that represents prosodic information that was contained in the original utterance and extracted by the speech recognizer. This depends on the availability of ASR's that are capable of producing prosodic information. b) An <input> tag can also contain additional <input> tags. Having additional input elements allows the representation to support future multi-modal inputs as well as finer-grained speech information, such as timestamps for individual words and word- level confidences. <input> <input mode="speech" confidence="0.5" timestamp-start="2000-04-03T0:00:00" timestamp-end="2000-04-03T0:00:00.2">fried</input> <input mode="speech" confidence="1.0" timestamp-start="2000-04-03T0:00:00.25" S Shanmugham IETF-Draft Page 81 MRCPv2 Protocol February, 2005 timestamp-end="2000-04-03T0:00:00.6">onions</input> </input> c) Finally, the <interpretation> element can contain <nomatch> and <noinput> elements, which describe situations in which the speech recognizer (or other media interpreter) received input that it was unable to process, or did not receive any input at all, respectively. NOMATCH Element The <nomatch> element under <input> is used to indicate that the semantic interpreter was unable to successfully match any input with confidence above the threshold. It can optionally contain the text of the best of the (rejected) matches. <interpretation> <instance/> <input confidence="0.1"> <nomatch/> </input> </interpretation> <interpretation> <instance/> <input mode="speech" confidence="0.1"> <nomatch>I want to go to New York</nomatch> </input> </interpretation> NOINPUT Element <noinput> indicates that there was no input-- a timeout occurred in the speech recognizer due to silence. <interpretation> <instance/> <input> <noinput/> </input> </interpretation> If there are multiple levels of inputs, it appears that the most natural place for <nomatch> and <noinput> elements is under the highest level of <input> for <no input>, and under the appropriate level of <interpretation> for <nomatch>. So <noinput> means "no input at all" and <nomatch> means "no match in speech modality" or "no match in dtmf modality". For example, to represent garbled speech combined with dtmf "1 2 3 4", we would have the following: <input> <input mode="speech"><nomatch/></input> S Shanmugham IETF-Draft Page 82 MRCPv2 Protocol February, 2005 <input mode="dtmf">1 2 3 4</input> </input> While <noinput> could be represented as an attribute of input, <nomatch> cannot, since it could potentially include PCDATA content with the best match. For parallelism, <noinput> is also an element. 9.7. Enrollment Results It will contain the following elements/tags to provide information associated with the voice enrollment. 1. Num-Clashes 2. Num-Good-Repetitions 3. Num-Repetitions-Still-Needed 4. Consistency-Status 5. Clash-Phrase-Ids 6. Transcriptions 7. Confusable-Phrases 1. Num-Clashes This is not a header field, but part of the recognition results. It is returned in a RECOGNITION-COMPLETE event. Its value represents the number of clashes that this pronunciation has with other pronunciations in an active enrollment session. The header field Clash-Threshold determines the sensitivity of the clash measurement. Clash testing can be turned off completely by setting Clash- Threshold to 0. num-clashes = "<num-clashes>" 1*DIGIT "</num-clashes>" CRLF 2. Num-Good-Repetitions This is not a header field, but part of the recognition results. It is returned in a RECOGNITION-COMPLETE event. Its value represents the number of consistent pronunciations obtained so far in an active enrollment session. num-good-repetitions = "<num-good-repetitions>" 1*DIGIT "</num-good-repetitions>" CRLF 3. Num-Repetitions-Still-Needed This is not a header field, but part of the recognition results. It is returned in a RECOGNITION-COMPLETE event. Its value represents the number of consistent pronunciations that must still be obtained before the new phrase can be added to the enrollment grammar. The number of consistent pronunciations required is determined by the S Shanmugham IETF-Draft Page 83 MRCPv2 Protocol February, 2005 header Num-Min-Consistent-Pronunciations, whose default value is two. The returned value must be 0 before the system will allow you to end an enrollment session for a new phrase. num-repetitions-still-needed = "<num-repetitions-still-needed>" 1*DIGIT "</num-repetitions-still-needed>" CRLF 4. Consistency-Status This is not a header field, but part of the recognition results. It is returned in a RECOGNITION-COMPLETE event. This is used to indicate how consistent the repetitions are when learning a new phrase. It can have the values of CONSISTENT, INCONSISTENT and UNDECIDED. consistency-status = "<consistency-status>" 1*ALPHA "</consistency-status>" CRLF 5. Clash-Phrase-Ids This is not a header field, but part of the recognition results. It is returned in a RECOGNITION-COMPLETE event. This gets filled with the phrase ids of the clashing pronunciation(s). This field is absent if there are no clashes. This MAY occur in RECOGNITION- COMPLETE events. phrase-id = "<item>" 1*ALPHA "</item>" CRLF clash-phrase-ids = "<clash-phrase-ids>" 1*phrase-id "</clash-phrase-ids>" CRLF 6. Transcriptions This is not a header field, but part of the recognition results. It is optionally returned in a RECOGNITION-COMPLETE event. This gets filled with the transcriptions returned in the last repetition of the phrase being enrolled. This MAY occur in RECOGNITION-COMPLETE events. transcription = "<item>" 1*OCTET "</item>" CRLF transcriptions = "<transcriptions>" 1*transcription "</transcriptions>" CRLF 7. Confusable-Phrases This is not a header field, but part of the recognition results. It is optionally returned in a RECOGNITION-COMPLETE event. This gets S Shanmugham IETF-Draft Page 84 MRCPv2 Protocol February, 2005 filled with the list of phrases from a command grammar that are confusable with the phrase being added to the personal grammar. This MAY occur in RECOGNITION-COMPLETE events. Confusable-phrase = "<item>" 1*OCTET "</item>" CRLF confusable-phrases = "<confusable-phrases>" 1*confusable-phrase "</confusable-phrases>" CRLF 9.8. DEFINE-GRAMMAR The DEFINE-GRAMMAR method, from the client to the server, provides a grammar and tells the server to define, download if needed and compile the grammar. If the server resource is in the recognition state, the DEFINE- GRAMMAR request MUST respond with a failure status. If the resource is in the idle state and is able to successfully load and compile the grammar the status MUST return a success code and the request-state MUST be COMPLETE. If the recognizer could not define the grammar for some reason, say the download failed or the grammar failed to compile, or the grammar was in an unsupported form, the MRCPv2 response for the DEFINE- GRAMMAR method MUST contain a failure status code of 407, and a completion-cause header field describing the failure reason. Example: C->S:MRCP/2.0 589 DEFINE-GRAMMAR 543257 Channel-Identifier: 32AECB23433801@speechrecog Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> S Shanmugham IETF-Draft Page 85 MRCPv2 Protocol February, 2005 may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C:MRCP/2.0 73 543257 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success C->S:MRCP/2.0 334 DEFINE-GRAMMAR 543258 Channel-Identifier: 32AECB23433801@speechrecog Content-Type: application/srgs+xml Content-Id: <helpgrammar@root-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <rule id="request"> I need help </rule> S->C:MRCP/2.0 73 543258 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success C->S:MRCP/2.0 723 DEFINE-GRAMMAR 543259 Channel-Identifier: 32AECB23433801@speechrecog Content-Type: application/srgs+xml Content-Id: <request2@field-level.store> Content-Length: 104 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE grammar PUBLIC "-//W3C//DTD GRAMMAR 1.0//EN" "http://www.w3.org/TR/speech- grammar/grammar.dtd"> <grammar xmlns="http://www.w3.org/2001/06/grammar" xml:lang="en" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/06/grammar http://www.w3.org/TR/speech-grammar/grammar.xsd" version="1.0" mode="voice" root="basicCmd"> S Shanmugham IETF-Draft Page 86 MRCPv2 Protocol February, 2005 <meta name="author" content="Stephanie Williams"/> <rule id="basicCmd" scope="public"> <example> please move the window </example> <example> open a file </example> <ruleref uri="http://grammar.example.com/politeness.grxml#startPo lite"/> <ruleref uri="#command"/> <ruleref uri="http://grammar.example.com/politeness.grxml#endPoli te"/> </rule> <rule id="command"> <ruleref uri="#action"/> <ruleref uri="#object"/> </rule> <rule id="action"> <one-of> <item weight="10"> open <tag>TAG-CONTENT-1</tag> </item> <item weight="2"> close <tag>TAG-CONTENT-2</tag> </item> <item weight="1"> delete <tag>TAG-CONTENT-3</tag> </item> <item weight="1"> move <tag>TAG-CONTENT-4</tag> </item> </one-of> </rule> <rule id="object"> <item repeat="0-1"> <one-of> <item> the </item> <item> a </item> </one-of> </item> <one-of> <item> window </item> <item> file </item> <item> menu </item> </one-of> </rule> </grammar> S Shanmugham IETF-Draft Page 87 MRCPv2 Protocol February, 2005 S->C:MRCP/2.0 69 543259 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success C->S:MRCP/2.0 155 RECOGNIZE 543260 Channel-Identifier: 32AECB23433801@speechrecog N-Best-List-Length: 2 Content-Type: text/uri-list Content-Length: 176 session:request1@form-level.store session:request2@field-level.store session:helpgramar@root-level.store S->C:MRCP/2.0 48 543260 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 48 START-OF-SPEECH 543260 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 486 RECOGNITION-COMPLETE 543260 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Waveform-URI: http://web.media.com/session123/audio.wav Content-Type: applicationt/x-nlsml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> 9.9. RECOGNIZE The RECOGNIZE method from the client to the server tells the recognizer to start recognition and provides it with a grammar to match for. The RECOGNIZE method can carry headers to control the sensitivity, confidence level and the level of detail in results provided by the recognizer. These headers override the current defaults set by a previous SET-PARAMS method. S Shanmugham IETF-Draft Page 88 MRCPv2 Protocol February, 2005 The RECOGNIZE method can be started in normal or hotword mode, and is specified by the Recognition-Mode header field. The default value is "normal". The RECOGNIZE method MUST carry the grammars that need to be activated for that RECOGNIZE method, in its message body. The grammars that need to be activated can be specified in one of 3 ways. The grammar content could be specified as a mime-content in the message body. It could be a simple list of grammar URIs specified in a mime-content of type text/uri-list, in which case the order of the URI refer to the precedence order of the grammars during the recognize. Or it could specified using a One-Of-Rule-Id- URI header field in the message, which refers to a specific <one-of> rule-id that should be available in the grammar specified in the body of the message. Note that the recognizer may also enroll the collected utterance in a personal grammar if the Enroll-utterance header field is set to true and an Enrollment is active (via an earlier execution of the START-PHRASE-ENROLLMENT method). If so, and if the RECOGNIZE request contains a Content-Id header field then the resulting grammar (which includes the personal grammar as a sub-grammar) can be referenced from elsewhere by using "session:foo", where "foo" is the value of the Content-Id header field. If the resource is in the recognizing state, the RECOGNIZE request MUST respond with a failure status. If the resource is in the Idle state and was able to successfully start the recognition, the server MUST return a success code and a request-state of IN-PROGRESS. This means that the recognizer is active and that the client should expect further events with this request-id. If the resource could not start a recognition, it MUST return a failure status code of 407 and contain a completion-cause header field describing the cause of failure. For the recognizer resource, this is the only request that can return request-state of IN-PROGRESS, meaning that recognition is in progress. When the recognition completes by matching one of the grammar alternatives or by a time-out without a match or for some other reason, the recognizer resource MUST send the client a RECOGNITION-COMPLETE event with the result of the recognition and a request-state of COMPLETE. For large grammars that can take a long time to compile and for grammars which are used repeatedly, the client could issue a DEFINE- GRAMMAR request with the grammar ahead of time. In such a case the client can issue the RECOGNIZE request and reference the grammar through the "session:" special URI. This also applies in general if the client wants to restart recognition with a previous inline grammar. S Shanmugham IETF-Draft Page 89 MRCPv2 Protocol February, 2005 Note that since the audio and the messages are carried over separate communication paths there may be a race condition between the start of the flow of audio and the receipt of the RECOGNIZE method. For example, if audio flow is started by the client at the same time as the RECOGNIZE method is sent, either the audio or the RECOGNIZE will arrive at the recognizer first. As another example, the client may chose to continuously send audio to the Server and signal the Server to recognize using the RECOGNIZE method. A number of mechanisms exist to resolve this condition and the mechanism chosen is left to the implementers of recognition resource. The recognizer should expect the media to start flowing when it receives the recognize request, and shouldn't buffer anything it receives beforehand. Example 1: C->S:MRCP/2.0 479 RECOGNIZE 543257 Channel-Identifier: 32AECB23433801@speechrecog Confidence-Threshold: 0.9 Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C:MRCP/2.0 48 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 49 START-OF-SPEECH 543257 IN-PROGRESS S Shanmugham IETF-Draft Page 90 MRCPv2 Protocol February, 2005 Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 467 RECOGNITION-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Waveform-URI: http://web.media.com/session123/audio.wav Content-Type: application/nlsml+xml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> Example 2: C->S:MRCP/2.0 479 RECOGNIZE 543257 Channel-Identifier: 32AECB23433801@speechrecog Confidence-Threshold: 0.9 Fetch-Timeout:20 One-Of-URI-Rule-Id:rule_list Content-Type: application/srgs+xml Content-Length: 176 <?xml version="1.0"? version="1.0" mode="voice" root="basicCmd"> <rule id="rule_list" scope="public"> <one-of> <item weight=10> <ruleref uri= "http://grammar.example.com/world-cities.grxml#canada"/> </item> <item weight=1.5> <ruleref uri= "http://grammar.example.com/world-cities.grxml#america"/> </item> <item weight=0.5> <ruleref uri= "http://grammar.example.com/world-cities.grxml#india"/> </item> </one-of> </rule> 9.10. STOP S Shanmugham IETF-Draft Page 91 MRCPv2 Protocol February, 2005 The STOP method from the client to the server tells the resource to stop recognition if one is active. If a RECOGNIZE request is active and the STOP request successfully terminated it, then the response header contains an active-request-id-list header field containing the request-id of the RECOGNIZE request that was terminated. In this case, no RECOGNITION-COMPLETE event will be sent for the terminated request. If there was no recognition active, then the response MUST NOT contain an active-request-id-list header field. Either way the response MUST contain a status of 200(Success). Example: C->S:MRCP/2.0 573 RECOGNIZE 543257 Channel-Identifier: 32AECB23433801@speechrecog Confidence-Threshold: 0.9 Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C:MRCP/2.0 47 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog C->S:MRCP/2.0 28 STOP 543258 200 Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 67 543258 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Active-Request-Id-List: 543257 S Shanmugham IETF-Draft Page 92 MRCPv2 Protocol February, 2005 9.11. GET-RESULT The GET-RESULT method from the client to the server can be issued when the recognizer is in the recognized state. This request allows the client to retrieve results for a completed recognition. This is useful if the client decides it wants more alternatives or more information. When the server receives this request it should re- compute and return the results according to the recognition constraints provided in the GET-RESULT request. The GET-RESULT request could specify constraints like a different confidence-threshold, or n-best-list-length. This feature is optional and the automatic speech recognition (ASR) engine may return a status of unsupported feature. Example: C->S:MRCP/2.0 73 GET-RESULT 543257 Channel-Identifier: 32AECB23433801@speechrecog Confidence-Threshold: 0.9 S->C:MRCP/2.0 487 543257 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Content-Type: application/nlsml+xml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> 9.12. START-OF-SPEECH This is an event from the recognizer to the client indicating that it has detected speech or a DTMF digit. This event is useful in implementing kill-on-barge-in scenarios when the synthesizer resource is in a different session than the recognizer resource and hence is not aware of an incoming audio source. In these cases, it is up to the client to act as a proxy and turn around and issue the BARGE-IN-OCCURRED method to the synthesizer resource. The recognizer resource also sends a unique proxy-sync-id in the header for this event, which is sent to the synthesizer in the BARGE-IN-OCCURRED method to the synthesizer. S Shanmugham IETF-Draft Page 93 MRCPv2 Protocol February, 2005 This event should be generated irrespective of whether the synthesizer and recognizer are on the same server or not. 9.13. START-INPUT-TIMERS This request is sent from the client to the recognition resource when it knows that a kill-on-barge-in prompt has finished playing. This is useful in the scenario when the recognition and synthesizer engines are not in the same session. Here when a kill-on-barge-in prompt is being played, you want the RECOGNIZE request to be simultaneously active so that it can detect and implement kill on barge-in. But at the same time you don't want the recognizer to start the no-input timers until the prompt is finished. The header Start-Input-Timers header field in the RECOGNIZE request will allow the client to say if the timers should be started or not. The recognizer should not start the timers until the client sends a START-INPUT-TIMERS method to the recognizer. 9.14. RECOGNITION-COMPLETE This is an Event from the recognizer resource to the client indicating that the recognition completed. The recognition result is sent in the MRCPv2 body of the message. The request-state field MUST be COMPLETE indicating that this is the last event with that request-id, and that the request with that request-id is now complete. The recognizer context still holds the results and the audio waveform input of that recognition till the next RECOGNIZE request is issued. A URI to the audio waveform MAY BE returned to the client in a waveform-uri header field in the RECOGNITION- COMPLETE event. The client can use this URI to retrieve or playback the audio. Note if an enrollment session was active on with the recognizer that the event can contain recognition or enrollment results depending on what was spoken. Example 1: C->S:MRCP/2.0 487 RECOGNIZE 543257 Channel-Identifier: 32AECB23433801@speechrecog Confidence-Threshold: 0.9 Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> S Shanmugham IETF-Draft Page 94 MRCPv2 Protocol February, 2005 <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C:MRCP/2.0 48 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 49 START-OF-SPEECH 543257 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C:MRCP/2.0 465 RECOGNITION-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Waveform-URI: http://web.media.com/session123/audio.wav Content-Type: application/nlsml+xml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> Example 2: S->C:MRCP/2.0 465 RECOGNITION-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Content-Type: application/nlsml+xml S Shanmugham IETF-Draft Page 95 MRCPv2 Protocol February, 2005 Content-Length: 123 <?xml version= "1.0"?> <result grammar="Personal-Grammar-URI" xmlns:mrcp="http://www.ietf.org/xml/ns/mrcpv2"> <mrcp:result-type type="ENROLLMENT" /> <mrcp:enrollment-result> <num-clashes> 2 </num-clashes> <num-good-repetitions> 1 </num-good-repetitions> <num-repetitions-still-needed> 1 </num-repetitions-still-needed> <consistency-status> consistent </consistency-status> <clash-phrase-ids> <item> Jeff </item> <item> Andre </item> </clash-phrase-ids> <transcriptions> <item> m ay b r ow k er </item> <item> m ax r aa k ah </item> </transcriptions> <confusable-phrases> <item> <phrase> call </phrase> <confusion-level> 10 </confusion-level> </item> </confusable-phrases> </mrcp:enrollment-result> </result> 9.15. START-PHRASE-ENROLLMENT The START-PHRASE-ENROLLMENT method sent from the client to the server starts a new phrase enrollment session during which the client may call RECOGNIZE to enroll a new utterance. This consists of a set of calls to RECOGNIZE in which the caller speaks a phrase several times so the system can "learn" it. The phrase is then added to a personal grammar (speaker-trained grammar), and the system can recognize it later. Only one phrase enrollment session may be active at a time. The Personal-Grammar-URI identifies the grammar that is used during enrollment to store the personal list of phrases. Once RECOGNIZE is called, the result is returned in a RECOGNITION-COMPLETE event and may contain either an enrollment result OR a recognition result for a regular recognition. Calling END-PHRASE-ENROLLMENT ends the ongoing phrase enrollment session, which is typically done after a sequence of successful calls to RECOGNIZE. This method can be called to commit the new phrase to the personal grammar or to abort the phrase enrollment session. S Shanmugham IETF-Draft Page 96 MRCPv2 Protocol February, 2005 The Personal-Grammar-URI, which specifies the grammar to contain the new enrolled phrase, will be created if it does not exist. Also, the personal grammar may ONLY contain phrases added via a phrase enrollment session. The Phrase-ID passed to this method will be used to identify this phrase in the grammar and will be returned as the speech input when doing a RECOGNIZE on the grammar. The Phrase-NL similarly will be returned in a RECOGNITION-COMPLETE event in the same manner as other NL in a grammar. The tag-format of this NL is vendor specific. If the client has specified Save-Best-Waveform as true, then the response after ending the phrase enrollment session should contain the location/URI of a recording of the best repetition of the learned phrase. Example: C->S: MRCP/2.0 123 START-PHRASE-ENROLLMENT 543258 Channel-Identifier: 32AECB23433801@speechrecog Num-Min-Consistent-Pronunciations: 2 Consistency-Threshold: 30 Clash-Threshold: 12 Personal-Grammar-URI: <personal grammar uri> Phrase-Id: <phrase id> Phrase-NL: <NL phrase> Weight: 1 Save-Best-Waveform: true S->C: MRCP/2.0 49 543258 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog 9.16. ENROLLMENT-ROLLBACK The ENROLLMENT-ROLLBACK method discards the last live utterance from the RECOGNIZE operation. This method should be invoked when the caller provides undesirable input such as non-speech noises, side- speech, commands, utterance from the RECOGNIZE grammar, etc. Note that this method does not provide a stack of rollback states. Executing ENROLLMENT-ROLLBACK twice in succession without an intervening recognition operation has no effect on the second attempt. Example: C->S: MRCP/2.0 49 ENROLLMENT-ROLLBACK 543261 Channel-Identifier: 32AECB23433801@speechrecog S->C: MRCP/2.0 49 543261 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog S Shanmugham IETF-Draft Page 97 MRCPv2 Protocol February, 2005 9.17. END-PHRASE-ENROLLMENT The END-PHRASE-ENROLLMENT method can only be called during an active phrase enrollment session, which was started by calling the method START-PHRASE-ENROLLMENT. It may NOT be called during an ongoing RECOGNIZE operation. It should be called when successive calls to RECOGNIZE have succeeded and Num-Repetitions-Still-Needed has been returned as 0 in the RECOGNITION-COMPLETE event to commit the new phrase in the grammar. Alternatively, it can be called by specifying the Abort-Phrase-Enrollment header to abort the phrase enrollment session. If the client has specified Save-Best-Waveform as true in the START- PHRASE-ENROLLMENT request, then the response should contain the location/URI of a recording of the best repetition of the learned phrase. Example: C->S: MRCP/2.0 49 END-PHRASE-ENROLLMENT 543262 Channel-Identifier: 32AECB23433801@speechrecog S->C: MRCP/2.0 123 543262 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Waveform-URI: <waveform uri> 9.18. MODIFY-PHRASE The MODIFY-PHRASE method sent from the client to the server is used to change the phrase ID, NL phrase and/or weight for a given phrase in a personal grammar. If no fields are supplied then calling this method has no effect and it is silently ignored. Example: C->S: MRCP/2.0 123 MODIFY-PHRASE 543265 Channel-Identifier: 32AECB23433801@speechrecog Personal-Grammar-URI: <personal grammar uri> Phrase-Id: <phrase id> New-Phrase-Id: <new phrase id> Phrase-NL: <NL phrase> Weight: 1 S->C: MRCP/2.0 49 543265 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog S Shanmugham IETF-Draft Page 98 MRCPv2 Protocol February, 2005 9.19. DELETE-PHRASE The DELETE-PHRASE method sent from the client to the server is used to delete a phase in a personal grammar added through voice enrollment or text enrollment. If the specified phrase doesn't exist, this method has no effect and it is silently ignored. Example: C->S: MRCP/2.0 123 DELETE-PHRASE 543266 Channel-Identifier: 32AECB23433801@speechrecog Personal-Grammar-URI: <personal grammar uri> Phrase-Id: <phrase id> S->C: MRCP/2.0 49 543266 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog 9.20. INTERPRET The INTERPRET method from the client to the server takes as input an interpret-text header, containing the text for which the semantic interpretation is desired, and returns, via the INTERPRETATION- COMPLETE event, an interpretation result which is very similar to the one returned from a RECOGNIZE method invocation. Only portions of the result relevant to acoustic matching are excluded from the result. The interpret-text header MUST be included in the INTERPRET request. Recognizer grammar data is treated in the same way as it is when issuing a RECOGNIZE method call. If a RECOGNIZE, RECORD or another INTERPRET operation is already in progress, invoking this method will cause the response to have a status code of 402, "Method not valid in this state", and a COMPLETE request state. Example: C->S: MRCP/2.0 123 INTERPRET 543266 Channel-Identifier: 32AECB23433801@speechrecog Interpret-Text: may I speak to Andre Roy Content-Type: application/srgs+xml Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> S Shanmugham IETF-Draft Page 99 MRCPv2 Protocol February, 2005 <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C: MRCP/2.0 49 543266 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C: MRCP/2.0 49 543267 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Content-Type: application/nlsml+xml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> 9.21. INTERPRETATION-COMPLETE This event from the recognition resource to the client indicates that the INTERPRET operation is complete. The interpretation result is sent in the body of the MRCP message. The request state MUST be set to COMPLETE. The completion-cause header MUST be included in this event and MUST be set to an appropriate value from the list of cause codes. Example: C->S: MRCP/2.0 123 INTERPRET 543266 Channel-Identifier: 32AECB23433801@speechrecog Interpret-Text: may I speak to Andre Roy Content-Type: application/srgs+xml S Shanmugham IETF-Draft Page 100 MRCPv2 Protocol February, 2005 Content-Id: <request1@form-level.store> Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to tokens --> <rule id="yes"> <one-of> <item xml:lang="fr-CA">oui</item> <item xml:lang="en-US">yes</item> </one-of> </rule> <!-- single language attachment to a rule expansion --> <rule id="request"> may I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C: MRCP/2.0 49 543266 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog S->C: MRCP/2.0 49 543267 200 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Content-Type: application/nlsml+xml Content-Length: 276 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> 9.22. DTMF Detection Digits received as DTMF tones will be delivered to the automatic speech recognition (ASR) engine in the RTP stream according to RFC 2833. The automatic speech recognizer (ASR) MUST support RFC 2833 to S Shanmugham IETF-Draft Page 101 MRCPv2 Protocol February, 2005 recognize digits and it MAY support recognizing DTMF tones in the audio. 10. Recorder Resource This resource captures the received audio and video and stores it as file. Their main applications would be for capturing speech audio that may be applied for recognition at a later time or recording voice or video mails. Both these applications require functionality above and beyond those specified by protocols such as RTSP such as Audio End-pointing(i.e detecting speech or silence). Detection of speech or silence may be required to start or stop recording. The support for video is optional and is mainly capturing video mails that may require the speech or audio processing mentioned above. 10.1. Recorder State Machine Idle Recording State State | | |---------RECORD------->| | | |<------STOP------------| | | |<--RECORD-COMPLETE-----| | | | |--------| | START-OF-SPEECH | | |------->| | | 10.2. Recorder Methods The recorder supports the following methods. recorder-Method = "RECORD" ; A / "STOP" ; B / "START-INPUT-TIMERS" ; C 10.3. Recorder Events The recorder may generate the following events. recorder-Event = "START-OF-SPEECH" ; D / "RECORD-COMPLETE" ; E 10.4. Recorder Header Fields S Shanmugham IETF-Draft Page 102 MRCPv2 Protocol February, 2005 A recorder messages may contain header fields containing request options and information to augment the Method, Response or Event message it is associated with. recorder-header = sensitivity-level / no-input-timeout / completion-cause / completion-reason / failed-uri / failed-uri-cause / record-uri / media-type / max-time / final-silence / capture-on-speech / ver-buffer-utterance / start-input-timers / new-audio-channel Header field where s g A B C D E __________________________________________________________ Sensitivity-Level R o o o - - - - No-Input-Timeout R o o o - - - - Completion-Cause R - - - - - - m Completion-Cause 2XX - - - o - - - Completion-Cause 4XX - - - m - - - Completion-Reason R - - - - - - m Completion-Reason 2XX - - - o - - - Completion-Reason 4XX - - - m - - - Start-Input-Timers R - - - o - - - Fetch-Timeout R o o o - - - - Failed-URI R - - - - - - o Failed-URI 4XX - - o - - - - Failed-URI-Cause R - - - - - - o Failed-URI-Cause 4XX - - o - - - - New-Audio-Channel R - - o - - - - Ver-Buffer-Utterance R - o o o - - - - Capture-On-Speech R o o o - - - - Media-Type R - - m - - - - Max-Time R o o o - - - - Final-Silence R o o o - - - - Record-URI R - - m - - - - Legend: (s) - SET-PARAMS, (g) - GET-PARAMS, (A) - RECORD, (B) - STOP, (C) - START-TIMERS , (D) - START-OF-SPEECH, (E) - RECORD- COMPLETE, (o) - Optional(Refer text for further constraints), (m) - Mandatory, (m) - Mandatory, (R) - Request, (r) - Response S Shanmugham IETF-Draft Page 103 MRCPv2 Protocol February, 2005 Sensitivity Level To filter out background noise and not mistake it for speech, the recorder may support a variable level of sound sensitivity. The sensitivity-level header allows the client to set this value on the recorder. This header field MAY occur in RECORD, SET-PARAMS or GET- PARAMS. A higher value for this field means higher sensitivity. The default value for this field is platform specific. sensitivity-level = "Sensitivity-Level" ":" 1*DIGIT CRLF No Input Timeout When recorder is started and there is no speech detected for a certain period of time, the recorder can send a RECORDER-COMPLETE event to the client and terminate the record operation. The no- input-timeout header field can set this timeout value. The value is in milliseconds. This header field MAY occur in RECORD, SET-PARAMS or GET-PARAMS. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. no-input-timeout = "No-Input-Timeout" ":" 1*DIGIT CRLF Completion Cause This header field MUST be part of a RECORD-COMPLETE, event coming from the recorder resource to the client. This indicates the reason behind the RECORD method completion. This header field MUST be sent in the RECORD responses, if they return with a failure status and a COMPLETE state. completion-cause = "Completion-Cause" ":" 1*DIGIT SP 1*VCHAR CRLF Cause-Code Cause-Name Description 000 success-silence RECORD completed with a silence at the end 001 success-maxtime RECORD completed after reaching Maximum recording time specified in record method. 002 noinput-timeout RECORD failed due to no input 003 uri-failure Failure accessing the record URI. 004 error RECORD request terminated prematurely due to a recorder error. Completion Reason This header field MAY be specified in a RECORD-COMPLETE event coming from the recorder resource to the client. This contains the reason S Shanmugham IETF-Draft Page 104 MRCPv2 Protocol February, 2005 text behind the RECORD request completion. This field can be use to communicate text describing the reason for the failure. completion-reason = "Completion-Reason" ":" quoted-string CRLF Failed URI When a record method needs to post the audio to an URI and access to the URI fails, the server SHOULD provide the failed URI in this header field in the method response. failed-uri = "Failed-URI" ":" Uri CRLF Failed URI Cause When a record method needs to post the audio to an URI and access to the URI fails, the server SHOULD provide the URI specific or protocol specific response code through this header field in the method response. This field has been defined as alphanumeric to accommodate all protocols, some of which might have a response string instead of a numeric response code. failed-uri-cause = "Failed-URI-Cause" ":" 1*alphanum CRLF Record URI When a record method contains this header field the server must capture the audio and store it. If the header field is empty, it MUST store it locally and generate a URI that points to it. This URI is then returned in the STOP response of the RECORD-COMPLETE events. If the header in the RECORD method specifies a URI the server must capture and store the audio at that location. If this header field is not specified in the RECORD message the server MUST capture the audio and send it in the STOP response or the RECORD-COMPLETE event as a message body. In the case, the message carrying the audio content would have this header field with a cid value pointing to the Content-ID in the message body. record-uri = "Record-URI" ":" Uri CRLF Media Type A RECORD method MUST contain this header field and specifies to the server the file format in which to store the captured audio or video. Media-type = "Media-Type" ":" media-type-value CRLF S Shanmugham IETF-Draft Page 105 MRCPv2 Protocol February, 2005 Max Time When recorder is started this specifies the maximum length of the recording, calculated from the time the actual capture and store begins and is not necessarily the time the RECORD method is recieved. After this time, the recording stops and the server must return a RECORD-COMPLETE event back to the client and will have a request-state of "COMPLETE".This header field MAY occur in RECORD, SET-PARAMS or GET-PARAMS. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. A value of zero means infinity and hence the recording will continue until one of the other stop conditions are met. The default value for this field is 0. max-time = "Max-Time" ":" 1*DIGIT CRLF Final Silence When recorder is started and the actual capture begins, this header field specifies the length of silence in the audio that is to be interpreted as the end of the recording. This header field MAY occur in RECORD, SET-PARAMS or GET-PARAMS. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. A value of zero means infinity and hence the recording will continue until one of the other stop conditions are met. The default value for this field is platform specific. final-silence = "Final-Silence" ":" 1*DIGIT CRLF Capture On Speech When recorder is started this header field specifies if the recorder should start capturing immediately(false) or wait for the end- pointing functionality to detect speech(true) before it start capturing. This header field MAY occur in the RECORD, SET-PARAMS or GET-PARAMS. The value for this field is a Boolean. The default value for this field is false. capture-on-speech = "Capture-On-Speech " ":" 1*DIGIT CRLF Ver-Buffer-Utterance This header field is the same as the one described for the Verification resource. This tells the server to buffer the utterance associated with this recording request into the verification buffer. Sending this header field is not valid if the verification buffer is not instantiated for the session. This buffer is shared across resources within a session and gets instantiated when a verification resource is added to this session and is released when the resource is released from the session. S Shanmugham IETF-Draft Page 106 MRCPv2 Protocol February, 2005 Start Input Timers This header MAY BE sent as part of the RECORD request. A value of false tells the recorder resource to start the operation, but not to start the no-input timer yet. The recorder resource should not start the timers until the client sends a START-INPUT-TIMERS request to the recorder resource. This is useful in the scenario when the recorder and synthesizer resources are not part of the same session. Here when a kill-on-barge-in prompt is being played, you may want the RECORD request to be simultaneously active so that it can detect and implement kill-on-barge-in. But at the same time you don't want the recorder resource to start the no-input timers until the prompt is finished. The default value is "true". start-input-timers = "Start-Input-Timers" ":" boolean-value CRLF New Audio Channel This header field is the same as the one described for the Recognizer resource. 10.5. Recorder Message Body The STOP response or the RECORD-COMPLETE events MAY contain a message body carrying the captured audio. This happens if the RECORD method did not have a Record-Uri header field in it. In this case, message carrying the audio content would have a Record-Uri header field with a cid value pointing to the message part that contains the recorded audio 10.6. RECORD The RECORD method moves the recorder resource to the Recording State. Depending on the header fields specified in the RECORD method the resource may start recording the audio immediately or wait for the end pointing functionality to detect speech in the audio. It then saves the audio to the URI supplied in the recording-uri header field. If the recording-uri is not specified, the server MUST capture the media onto a local disk and return a URI pointing to the recorded audio in the RECORD-COMPLETE event. The server MUST support HTTP and file URI schemes. If a RECORD operation is already in progress, invoking this method will cause the response to have a status code of 402, "Method not valid in this state", and a COMPLETE request state. If the recording-uri is not valid, a status code of 404, "Illegal Value for Header", will be returned in the response. If it is S Shanmugham IETF-Draft Page 107 MRCPv2 Protocol February, 2005 impossible for the server to create the requested file, a status code of 407, "Method or Operation Failed", will be returned. When the recording operation is initiated the response will indicate an IN-PROGRESS request state. The server MAY generate a subsequent START-OF-SPEECH event when speech is detected. Upon completion of the recording operation, the server will generate a RECORDING- COMPLETE event. Example: C->S:MRCP/2.0 386 RECORD 543257 Channel-Identifier: 32AECB23433802@recorder Record-URI: file://mediaserver/recordings/myfile.wav Capture-On-Speech: true Final-Silence: 300 Max-Time: 6000 S->C:MRCP/2.0 48 456234 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder S->C:MRCP/2/0 49 START-OF-SPEECH 456234 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder S->C:MRCP/2.0 54 RECORDING-COMPLETE 456234 COMPLETE Channel-Identifier: 32AECB23433802@recorder Completion-Cause: 000 success-silence Record-URI: file://mediaserver/recordings/myfile.wav 10.7. STOP The STOP method moves the recorder from the recording state back to the idle state. If the recording was a success the STOP response contains a Record-URI header pointing to the recorded audio file on the server or to a MIME part in the body of the message containing the recorded audio file. The STOP method may have a Trim-Length header field, in which case the specified length of audio is trimmed from the end of the recording after the stop. Example: C->S:MRCP/2.0 386 RECORD 543257 Channel-Identifier: 32AECB23433802@recorder Record-URI: file://mediaserver/recordings/myfile.wav Capture-On-Speech: true Final-Silence: 300 Max-Time: 6000 S->C:MRCP/2.0 48 456234 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder S Shanmugham IETF-Draft Page 108 MRCPv2 Protocol February, 2005 S->C:MRCP/2/0 49 START-OF-SPEECH 456234 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder C->S:MRCP/2.0 386 STOP 543257 Channel-Identifier: 32AECB23433802@recorder Trim-Length: 200 S->C:MRCP/2.0 48 456234 200 COMPLETE Channel-Identifier: 32AECB23433802@recorder Completion-Cause: 000 success Record-URI: file://mediaserver/recordings/myfile.wav 10.8. RECORD-COMPLETE If the recording completes due to no-input, silence after speech or max-time the server MUST generate the RECORD-COMPLETE event to the client with a request-state of "COMPLETE". If the recording was a success the RECORD-COMPLETE event contains a Record-URI header pointing to the recorded audio file on the server or to a MIME part in the body of the message containing the recorded audio file. Example: C->S:MRCP/2.0 386 RECORD 543257 Channel-Identifier: 32AECB23433802@recorder Record-URI: file://mediaserver/recordings/myfile.wav Capture-On-Speech: true Final-Silence: 300 Max-Time: 6000 S->C:MRCP/2.0 48 456234 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder S->C:MRCP/2/0 49 START-OF-SPEECH 456234 IN-PROGRESS Channel-Identifier: 32AECB23433802@recorder S->C:MRCP/2.0 48 RECORD-COMPLETE 456234 COMPLETE Channel-Identifier: 32AECB23433802@recorder Completion-Cause: 000 success Record-URI: file://mediaserver/recordings/myfile.wav 10.9. START-INPUT-TIMERS This request is sent from the client to the recorder resource when it knows that a kill-on-barge-in prompt has finished playing. This is useful in the scenario when the recorder and synthesizer resources are not in the same session. Here when a kill-on-barge-in prompt is being played, you want the RECORD request to be simultaneously active so that it can detect and implement kill on barge-in. But at the same time you don't want the recorder resource S Shanmugham IETF-Draft Page 109 MRCPv2 Protocol February, 2005 to start the no-input timers until the prompt is finished. The header Start-Input-Timers header field in the RECORD request will allow the client to say if the timers should be started or not. In the above case the recorder resource should not start the timers until the client sends a START-INPUT-TIMERS method to the recorder. S Shanmugham IETF-Draft Page 110 MRCPv2 Protocol February, 2005 11. Speaker Verification and Identification This section describes the methods, responses and events needed for doing Speaker Verification / Identification. Speaker verification is a voice authentication feature that can be used to identify the speaker in order to grant the user access to sensitive information and transactions. To do this, a recorded utterance is compared to a voiceprint previously stored for that user. Verification consists of two phases: a designation phase to establish the claimed identity of the caller and an execution phase in which a voiceprint is either created (training) or used to authenticate the claimed identity (verification). The resource name is 'speakverify'. Speaker identification identifies the speaker from a set of valid users, such as family members. It may also be referred to, sometimes as Multi-Verification. Identification can be performed on a small set of users or for a large population. This feature is useful for applications where multiple users share the same account number, but where the individual speaker must be uniquely identified from the group. Speaker identification is also done in two phases, a designation phase and an execution phase. It is possible for a speaker verification resource to share the same session as an existing recognizer resource or a speaker verification session can be set up to operate in standalone mode, without a recognizer resource sharing the same session. In order to share the same session, the SDP/SIP INVITE message for the verification resource MUST also include the recognizer resource request. Otherwise, an independent verification resource, running on the same physical server or a separate one, will be set up. Some of the speaker verification methods, described below, apply only to a specific mode of operation. The verification resource supports buffering that allow the user to buffer the verification data from an utterance and then process this utterance later. This is different from collecting waveforms and processing them using the VERIFY method that operates directly on the incoming audio stream, because this buffering mechanism does not simply accumulate utterance data to a buffer. This buffer is iwned by the verification resource but shares write access with other input resources such as the recognizer and recorder resources. When both the recognition and verification resources share the same session, additional information gathered by the recognition resource may be saved with these buffers to improve verification performance. This buffer can be cleared by a CLEAR-BUFFER request from the client and is freed when the resource is 'speakverify' is freed. S Shanmugham IETF-Draft Page 111 MRCPv2 Protocol February, 2005 11.1. Speaker Verification State Machine Speaker Verification has a concept of a training or verification sessions. Starting one of these sessions does not change the state of the verification resource, i.e. it remains idle. Once a verification or training session is started, then utterances are trained or verified by calling the VERIFY or VERIFY-FROM-BUFFER method. The state of the Speaker Verification resources goes from IDLE to VERIFYING state each time VERIFY or VERIFY-FROM-BUFFER is called. As mentioned above, the verification resource has a verification buffer associated with it. This allows the buffering of speech utterances for the purposes of verification, identification or training from the buffered speech. This buffer is owned by the verification resource but other input resources such as the recognition resource or recorder resource share write access to it. This allows the speech received as part of a recognition or recording scenario to be later used for verification, identification or training. Note that access the buffer is limited to one operation at time. Hence when resource is doing read, write or delete operation such as a RECOGNIZE with ver-buffer-utternance turned on, another operation involving the buffer such a CLEAR-BUFFER would fail with a status of 402. 11.2. Speaker Verification Methods Speaker Verification supports the following methods. verification-method = "START-SESSION" ; A / "END-SESSION" ; B / "QUERY-VOICEPRINT" ; C / "DELETE-VOICEPRINT" ; D / "VERIFY" ; E / "VERIFY-FROM-BUFFER" ; F / "VERIFY-ROLLBACK" ; G / "STOP" ; H / "CLEAR-BUFFER" ; I / "START-INPUT-TIMERS" ; J / "GET-INTERMEDIATE-RESULT" ; K These methods allow the client to control the mode and target of verification or identification operations within the context of a session. All the verification input cycles that occur within a session may be used to create, update, or validate against the voiceprint specified during the session. At the beginning of each session the verification resource is reset to a known state. Verification/identification operations can be executed against live or buffered audio. The verification resource provides methods for S Shanmugham IETF-Draft Page 112 MRCPv2 Protocol February, 2005 for collecting and evaluating live audio data, and methods for controlling the verification resource and adjusting its configured behavior. There are no specific methods for collecting buffered audio data. This is accomplished by calling VERIFY, RECOGNIZE or RECORD as appropriate for the resource, with the header ver-buffer-utterance. Then, when the following method is called verification is performed using the set of buffered audio. 1. VERIFY-FROM-BUFFER The following methods provide controls for verification of live audio utterances : 1. VERIFY 2. START-INPUT-TIMERS The following methods provide controls for configuring the verification resource and for establishing resource states : 1. START-SESSION 2. END-SESSION 3. QUERY-VOICEPRINT 4. DELETE-VOICEPRINT 5. VERIFY-ROLLBACK 6. STOP 7. CLEAR-BUFFER The following method allows the polling a Verification in progress for intermediate results. 8. GET-INTERMEDIATE-RESULTS 11.3. Verification Events Speaker Verification may generate the following events. verification-event = "VERIFICATION-COMPLETE" ; L / "START-OF-SPEECH" ; M 11.4. Verification Header Fields A Speaker Verification request may contain header fields containing request options and information to augment the Request, Response or Event message it is associated with. verification-header = repository-uri / voiceprint-identifier / verification-mode / adapt-model S Shanmugham IETF-Draft Page 113 MRCPv2 Protocol February, 2005 / abort-model / security-level / num-min-verification-phrases / num-max-verification-phrases / no-input-timeout / save-waveform / waveform-uri / voiceprint-exists / ver-buffer-utterance / input-waveform-uri / completion-cause / completion-reason / speech-complete-timeout / new-audio-channel / abort-verification / start-input-timers Header field where s g A B C D E F G H I J K L M __________________________________________________________ Repository-URI R - - m - m m - - - - - - - - - Voiceprint-Identifier R - - m - m m - - - - - - - - - Verification-Mode R o o o - - - - - - - - - - - - Adapt-Model R o o o - - - - - - - - - - - - Abort-Model R - - - o - - - - - - - - - - - Security-Level R o o o - - - - - - - - - - - - Num-Min-Verification-P. R o o o - - - - - - - - - - - - Num-Max-Verification-P. R o o o - - - - - - - - - - - - No-Input-Timeout R o o - - - - o - - - - - - - - Save-Waveform R o o - - - - o - - - - - - - - Waveform-URI R - - - - - - - - - - - - - o - Input-Waveform-URI R - - - - - - o - - - - - - - - Ver-Buffer-Utterance R o o - - - - o - - - - - - - - Completion-Cause R - - - - - - - - - - - - - m - Completion-Cause 2XX - - - - m m - o - - - - - - - Completion-Cause 4XX - - - - m m m m - - - - - - - Completion-Reason R - - - - - - - - - - - - - m - Completion-Reason 2XX - - - - m m - o - - - - - - - Completion-Reason 4XX - - - - m m m m - - - - - - - Start-Input-Timers R - - - - - - o - - - - - - - - Fetch-Timeout R o o o o - - - - - - - - - - - Failed-URI R - - - - - - - - - - - - - o - Failed-URI 4XX - - o o - - - - - - - - - - - Failed-URI-Cause R - - - - - - - - - - - - - o - Failed-URI-Cause 4XX - - o o - - - - - - - - - - - New-Audio-Channel R - - - o - - o - - - o - - - - Abort-Verification R - - - - - - - - - m - - - - - Speech-Complete-Timeout R o o - - - - o - - - - - - - - Voice-Print-Exists 2XX - - - - m m - - - - - - - - - S Shanmugham IETF-Draft Page 114 MRCPv2 Protocol February, 2005 Legend: (s) - SET-PARAMS, (g) - GET-PARAMS, (A) - START-SESSION, (B) - END-SESSION, (C) - QUERY-VOICE-PRINT, (D) DELETE-VOICE-PRINT, (E) - VERIFY, (F) - VERIFY-FROM-BUFFER, (G) - VERIFY-ROLLBACK, (H) - STOP, (I) - CLEAR-BUFFER, (J) - START-INPUT-TIMERS , (K) - GET- INTERMEDIATE-RESULTS, (L) - VERIFICATION-COMPLETE, (M) - START-OF- SPEECH, (o) - Optional(Refer text for further constraints), (m) - Mandatory, (R) - Request, (r) - Response Repository-URI This header specifies the voiceprint repository to be used or referenced during speaker verification or identification operations. This header field is required in START-SESSION, QUERY-VOICEPRINT and DELETE-VOICEPRINT methods. repository-uri = "Repository-URI" ":" Uri CRLF Voiceprint-Identifier This header field specifies the claimed identity for voice verification applications. The claimed identity may be used to specify an existing voiceprint or to establish a new voiceprint. This header field is required in QUERY-VOICEPRINT and DELETE- VOICEPRINT methods. The Voiceprint-Identifier is required in the SESSION-START method for verification operations. For Identification or Multi-Verification operations this header may contain a list of voice print identifiers separated by semi-colon. For identification operations you could also specify a voice print group identifier instead of a list of voice print identifiers. All voice print group identifiers have an extension of ".vpg". The creation of such group identifier objects is left to mechanism outside this protocol. voiceprint-identifier = "Voiceprint-Identifier" ":" 1*VCHAR "." 3VCHAR *[";" 1*VCHAR "." 3VCHAR] CRLF Verification-Mode This header field specifies the mode of the verification resource and is set in SESSION-START method. Acceptable values indicate whether the verification session should train a voiceprint ("train") or verify/identify using an existing voiceprint ("verify"). Training and verification sessions both require the voiceprint Repository-URI to be specified in the START-SESSION. In many usage scenarios, however, the system cannot know the speaker's claimed identity until the speaker says, for example, their account number. In order to allow the first few utterances of a dialog to be both recognized and verified, the verification resource on the MRCP server retains an audio buffer. In this audio buffer, the MRCP S Shanmugham IETF-Draft Page 115 MRCPv2 Protocol February, 2005 server will accumulate recognized utterances in memory. The application can later execute a verification method and apply the buffered utterances to the current verification session. The buffering methods are used for this purpose. When buffering is used, subsequent input utterances are added to the audio buffer for later analysis. Some voice user interfaces may require additional user input that should not be analyzed for verification. For example, the user's input may have been recognized with low confidence and thus require a confirmation cycle. In such cases, the client should not execute the VERIFY or VERIFY-FROM-BUFFER methods to collect and analyze the caller's input. A separate recognizer resource can analyze the caller's response without any participation on behalf of the verification resource. Once the following conditions have been met: 1. Voiceprint identity has been successfully established through the voiceprint identifier header fields of the -VOICEPRINT method, and 2. the verification mode has been set to one of "train" or "verify", the verification resource may begin providing verification information during verification operations. The verification resource MUST reach one of the two major states ("train" or "verify") if the above two conditions hold, or it MUST report an error condition in the MRCP status code to indicate why the verification resource is not ready for action. The value of verification-mode is persistent within a verification session. Changing the mode to a different value than the previous setting causes the verification resource to report an error if the previous setting was either "train" or "verify". If the mode is changed back to its previous value, the operation may continue. verification-mode = "Verification-Mode" ":" verification-mode-string verification-mode-string = "train" / "verify" Adapt-Model This header field indicates the desired behavior of the verification resource after a successful verification execution. If the value of this header is "true", the audio collected during the verification session is may be to update the voiceprint to account for ongoing changes in a speaker's incoming speech characteristics. If the value is "false" (the default), the voiceprint is not updated with the latest audio. This header field MAY only occur in START-SESSION method. adapt-model = "Adapt-Model" ":" Boolean-value CRLF S Shanmugham IETF-Draft Page 116 MRCPv2 Protocol February, 2005 Abort-Model The Abort-Model header field indicates the desired behavior of the verification resource upon session termination. If the value of this header is "true", the pending changes to a voiceprint due to verification training or verification adaptation are discarded. If the value is "false" (the default), the pending changes for a training session or a successful verification session are committed to the voiceprint repository. A value of "true" for Abort-Model overrides a value of "true" for the Adapt-Model header field. This header field MAY only occur in END-SESSION method. abort-model = "Abort-Model" ":" Boolean-value CRLF Security-Level The Security-Level header field determines the range of verification scores in which a decision of 'accepted' may be declared. This header field MAY occur in SET-PARAMS, GET-PARAMS and START-SESSION methods. It can be "high" (highest security level), "medium-high", "medium" (normal security level), "medium-low", or "low" (low security level). The default value is platform specific. security-level = "Security-Level" ":" security-level-string CRLF security-level-string = "high" / "medium-high" / "medium" / "medium-low" / "low" Num-Min-Verification-Phrases The Num-Min-Verification-Phrases header field is used to specify the minimum number of valid utterances before a positive decision is given for verification. The value for this header is integer and the default value is 1. The verification resource should not announce a decision of 'accepted' unless the Num-Min-Verification-Phrases utterances are available. The minimum value is 1. num-min-verification-phrases = "Num-Min-Verification-Phrases" ":" 1*DIGIT CRLF S Shanmugham IETF-Draft Page 117 MRCPv2 Protocol February, 2005 Num-Max-Verification-Phrases The Num-Max-Verification-Phrases header field is used to specify the number of valid utterances required before a decision is forced for verification. The verification resource MUST NOT return a decision of 'undecided' once Num-Max-Verification-Phrases have been collected and used to determine a verification score. The value for this header is integer and the minimum value is 1. num-min-verification-phrases = "Num-Max-Verification-Phrases" ":" 1*DIGIT CRLF No-Input-Timeout The No-Input-Timeout header field sets the length of time from the start of the verification timers (see START-INPUT-TIMERS) until the declaration of a no-input event in the VERIFICATION-COMPLETE server event message. The value is in milliseconds. This header field MAY occur in VERIFY, SET-PARAMS or GET-PARAMS. The value for this field ranges from 0 to MAXTIMEOUT, where MAXTIMEOUT is platform specific. The default value for this field is platform specific. no-input-timeout = "No-Input-Timeout" ":" 1*DIGIT CRLF Save-Waveform This header field allows the client to indicate to the verification resource that it MUST save the audio stream that was used for verification/identification. The verification resource MUST then record the audio and make it available to the client in the form of a URI returned in the waveform-uri header field in the VERIFICATION-COMPLETE event. If there was an error in recording the stream or the audio clip is otherwise not available, the verification resource MUST return an empty waveform-uri header field. The default value for this field is "false". This header field MAY appear in the VERIFY method, but NOT in the VERIFY-FROM- BUFFER method since it can control whether or not to save the waveform for live verification / identification operations only. save-waveform = "Save-Waveform" ":" boolean-value CRLF Waveform-URI If the save-waveform header field is set to true, the verification resource MUST record the incoming audio stream of the verification into a file and provide a URI for the client to access it. This header MUST be present in the VERIFICATION-COMPLETE event if the save-waveform header field is set to true. The URI value of the S Shanmugham IETF-Draft Page 118 MRCPv2 Protocol February, 2005 header MUST be NULL if there was some error condition preventing the server from recording. Otherwise, the URI generated by the server SHOULD be globally unique across the server and all its verification sessions. The URI SHOULD BE available until the session is torn down. Since the save-waveform header field applies only to live verification / identification operations, the waveform-uri will only be returned in the VERIFICATION-COMPLETE event for live verification / identification operations. waveform-uri = "Waveform-URI" ":" Uri CRLF Voiceprint-Exists This header field is returned in a QUERY-VOICEPRINT or DELETE- VOICEPRINT response. This is the status of the voiceprint specified in the QUERY-VOICEPRINT method. For the DELETE-VOICEPRINT method this field indicates the status of the voiceprint as the method execution started. voiceprint-exists = "Voiceprint-Exists" ":" Boolean-value CRLF Ver-Buffer-Utterance This header field is used to indicate that this utterance could be later considered for Speaker Verification. This way, an application can buffer utterances while doing regular recognition or verification activities and speaker verification can later be requested on the buffered utterances. This header field is OPTIONAL in the RECOGNIZE, VERIFY or RECORD method. The default value for this field is "false". ver-buffer-utterance = "Ver-Buffer-Utterance" : Boolean-value CRLF Input-Waveform-Uri This optional header field specifies an audio file that has to be processed according to the current verification mode, either to train the voiceprint or verify the user. This enables the client to implement the buffering use case also in the case where the recognizer and verification resources live in two sessions. It MAY be part of the VERIFY method. input-waveform-uri = "Input-Waveform-URI" ":" Uri CRLF Completion-Cause S Shanmugham IETF-Draft Page 119 MRCPv2 Protocol February, 2005 This header field MUST be part of a VERIFICATION-COMPLETE event coming from the verification resource to the client. This indicates the reason behind the VERIFY or VERIFY-FROM-BUFFER method completion. This header field MUST BE sent in the VERIFY, VERIFY- FROM-BUFFER, QUERY-VOICEPRINT responses, if they return with a failure status and a COMPLETE state. completion-cause = "Completion-Cause" ":" 1*DIGIT SP 1*VCHAR CRLF Cause-Code Cause-Name Description 000 success VERIFY or VERIFY-FROM-BUFFER request completed successfully. The verify decision can be "accepted", "rejected", or "undecided". 001 error VERIFY or VERIFY-FROM-BUFFER Request terminated prematurely due to a verification resource or system error. 002 no-input-timeout VERIFY request completed with no result due to a no-input-timeout. 003 too-much-speech-timeout VERIFY request completed result due to too much speech 004 speech-too-early VERIFY request completed with no result due to spoke too soon. 005 buffer-empty VERIFY-FROM-BUFFER request completed with no result due to empty buffer. 006 out-of-sequence Verification operation failed due to out-of-sequence method invocations. For example calling VERIFY before QUERY-VOICEPRINT. 007 repository-uri-failure Failure accessing Repository URI. 008 repository-uri-missing Repository-uri is not specified. 009 voiceprint-id-missing Voiceprint-identification is not specified. 010 voiceprint-id-not-exist Voiceprint-identification doesn't exist in the voiceprint repository. Completion Reason This header field MAY be specified in a VERIFICATION-COMPLETE event coming from the verifier resource to the client. This contains the reason text behind the VERIFY request completion. This field can be use to communicate text describing the reason for the failure. S Shanmugham IETF-Draft Page 120 MRCPv2 Protocol February, 2005 completion-reason = "Completion-Reason" ":" quoted-string CRLF Speech Complete Timeout This header field is the same as the one described for the Recognizer resource. New Audio Channel This header field is the same as the one described for the Recognizer resource. Abort-Verification This header field MUST BE sent in a STOP method to indicate if the current VERIFY method in progress should be aborted or if it should stop verifying and return the verification results until that point in time. A value of "true" will abort the request and discard the results. A value of "false" would stop verification and return the verification result in the STOP response. Abort-verification = "Abort-Verification " : Boolean-value CRLF Start Input Timers This header MAY BE sent as part of a VERIFY request. A value of false tells the verification resource to start the VERIFY operation, but not to start the no-input timer yet. The verification resource should not start the timers until the client sends a START-INPUT- TIMERS request to the resource. This is useful in the scenario when the verifier and synthesizer resources are not part of the same session. Here when a kill-on-barge-in prompt is being played, you may want the VERIFY request to be simultaneously active so that it can detect and implement kill-on-barge-in. But at the same time you don't want the verification resource to start the no-input timers until the prompt is finished. The default value is "true". start-input-timers = "Start-Input-Timers" ":" boolean-value CRLF 11.5. Verification Result Elements The verification results will be returned as XML data in a VERIFICATION-COMPLETE event containing an NLSML document, having a MIME-type application/nlsml+xml. The XML Schema and DTD for this portion XML data is provided in a normative form in the Appendix. MRCP-specific tag additions to this XML result format described in S Shanmugham IETF-Draft Page 121 MRCPv2 Protocol February, 2005 this section MUST be in the MRCPv2 namespace. In the result structure, they must either be prefixed by a namespace prefix declared within the result or must be children of an element identified as belonging to the respective namespace. For details on how to use XML Namespaces, see [21]. Section 2 of [21] provides details on how to declare namespaces and namespace prefixes. Example 1: <?xml version="1.0"?> <result grammar="What-Grammar-URI" xmlns:mrcp="http://www.ietf.org/xml/ns/mrcpv2"> <mrcp:result-type type="VERIFICATION" /> <mrcp:verification-result> <voiceprint id="johnsmith"> <adapted> true </adapted> <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.98514 </verification-score> </incremental> <cumulative> <num-frames> 1000 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.91725</verification-score> </cumulative> </voiceprint> <voiceprint id="marysmith"> <cumulative> <verification-score> 0.93410 </verification-score> </cumulative> </voiceprint> <voiceprint uri="juniorsmith"> <cumulative> <verification-score> 0.74209 </verification-score> </cumulative> </voiceprint> </mrcp:verification-result> </result> Example 2: <?xml version="1.0"?> <result grammar="What-Grammar-URI" xmlns:mrcp="http://www.ietf.org/xml/ns/mrcpv2"> xmlns:xmpl="http://www.example.org/2003/12/mrcpv2"> <mrcp:result-type type="VERIFICATION" /> <mrcp:verification-result> <voiceprint id="johnsmith"> S Shanmugham IETF-Draft Page 122 MRCPv2 Protocol February, 2005 <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <needmoredata> true </needmoredata> <verification-score> 0.88514 </verification-score> <xmpl:raspiness> high </xmpl:raspiness> <xmpl:emotion> sadness </xmpl:emotion> </incremental> <cumulative> <num-frames> 1000 </num-frames> <device> cellular-phone </device> <gender> female </gender> <needmoredata> false </needmoredata> <verification-score> 0.9345 </verification-score> </cumulative> </voiceprint> </mrcp:verification-result> </result> Enrollment results XML markup can contain the following elements/tags: 1. Voice-Print 2. Incremental 3. Cumulative 4. Decision 5. Utterance-Length 6. Device 7. Gender 8. Adapted 9. Verification-Score 10. Vendor-Specific-Results 1. VoicePrint This element in the verification results provides information on how the speech data matched a single voice print. The result data returned may have more than one such entity in it in the case of Identification or Multi-Verification. Each voice-print element and the XML data within the element describe verification result information for how well the speech data matched that particular voice-print. The list of voice-print element data are ordered according to their cumulative verification match scores, with the highest as the first. 2. Cumulative Within each voice-print element there MUST BE a "cumulative" element with the cumulative scores of how well multiple utterances matched the voice-print. S Shanmugham IETF-Draft Page 123 MRCPv2 Protocol February, 2005 3. Incremental The first voice-print element there MAY contain an "incremental" element with the incremental scores of how well the last utterance matched the voice-print. 4. Decision This element is found within the incremental or cumulative element within the verification results. Its value indicates the decision as determined by verification. It can have the values of "accepted", "rejected" or "undecided". 5. Utterance-Length This element is found within the incremental or cumulative element within the verification results. Its value indicates the size of the last utterance or the cumulated set of utterances in milliseconds. 6. Device This element is found within the incremental or cumulative element within the verification results. Its value indicates the apparent type of device used by the caller as determined by verification. It can have the values of "cellular-phone", "electret-phone", "carbon- button-phone" and "unknown". 7. Gender This element is found within the incremental or cumulative element within the verification results. Its value indicates the apparent gender of the speaker as determined by verification. It can have the values of "male", "female" or "unknown". 8. Adapted This element is found within the voice-print element within the verification results. When verification is trying to confirm the voiceprint, this indicates if the voiceprint has been adapted as a consequence of analyzing the source utterances. It is not returned during verification training. The value can be "true" or "false". 9. Verification-Score This element is found within the incremental or cumulative element within the verification results. Its value indicates the score of the last utterance as determined by verification. During verification, the higher the score the more likely it is that the speaker is the same one as the one who spoke the voiceprint utterances. During training, the higher the score the more likely the speaker is to have spoken all of the analyzed utterances. The value is a floating point between 0.0 and 1.0. If there are no such utterances the score is 0. It should be noted that though the value of the verification score is between 0.0 and 1.0 it should NOT BE interpreted as a probability value. S Shanmugham IETF-Draft Page 124 MRCPv2 Protocol February, 2005 11. Vendor-Specific-Results This section describes the method used to describe vendor specific results using the xml syntax. Vendor-specific additions to the default result format MUST belong to the vendor's own namespace. In the result structure, they must either be prefixed by a namespace prefix declared within the result or must be children of an element identified as belonging to the respective namespace. 11.6. START-SESSION The START-SESSION method starts a Speaker Verification or Identification session. Execution of this method forces the verification resource into a known initial state. If this method is called during an ongoing verification session, the previous session is implicitly aborted. If this method is invoked when VERIFY or VERIFY-FROM-BUFFER is active, it would fail with a status code of 402. Upon completion of the START-SESSION method, the verification resource MUST terminate any ongoing verification sessions, and clear any voiceprint designation. A verification session needs to establish the voice print repository that will be used as part of this session. This is specified through the "Repository-URI" header field, in which a URI pointing to the location of the voiceprint repository is given. It also establishes the voice-print that is going to be matched or trained during that verification session through the Voiceprint- Identifier header field. If this is an Identification session or if you wanted to do Multi-Verification, this header would contain a list of semi-colon separated voice print identifiers. The header field "Adapt-Model" may also be present in the start session method to indicate whether or not to adapt a voiceprint with data collected during the session (if the voiceprint verification phase succeeds). By default the voiceprint model should NOT be adapted with data from a verification session. The START-SESION must also establish if the session is for a train or verify a voice-print. Hence the Verification-Mode header field MUST BE sent in this method. The value of the "Verification-Mode" header field MUST be one of either "train" or "verify". Before a verification/identification resource is started, only VERIFY-ROLLBACK and generic SET-PARAMS and GET-PARAMS operations can be performed. The server should return 402(Method not valid in this state) for all other operations, such as VERIFY, QUERY-VOICEPRINT. S Shanmugham IETF-Draft Page 125 MRCPv2 Protocol February, 2005 A single session can be active at one time. Example: C->S: MRCP/2.0 123 START-SESSION 314161 Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/voiceprintdbase/ Voiceprint-Identifier: johnsmith.voiceprint Adapt-Model: true S->C: MRCP/2.0 49 314161 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.7. END-SESSION The END-SESSION method terminates an ongoing verification session and releases the verification voiceprint model in one of three ways: a. aborting - the voiceprint adaptation or creation may be aborted so that the voiceprint remains unchanged (or is not created). b. committing - when terminating a voiceprint training session, the new voiceprint is committed to the repository. c. adapting - an existing voiceprint is modified using a successful verification. The header field "Abort-Model" may be included in the END-SESSION to control whether or not to abort any pending changes to the voiceprint. The default behavior is to commit (not abort) any pending changes to the designated voiceprint. The END-SESSION method may be safely executed multiple times without first executing the START-SESSION method. Any additional executions of this method without an intervening use of the START-SESSION method have no effect on the system. Example: This example assumes there are a training session or a verification session in progress. C->S: MRCP/2.0 123 END-SESSION 314174 Channel-Identifier: 32AECB23433801@speakverify Abort-Model: true S->C: MRCP/2.0 49 314174 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.8. QUERY-VOICEPRINT The QUERY-VOICEPRINT method is used to get a status on a particular voice-print and can be used to find if a voice-print or repository exists and if its trained. S Shanmugham IETF-Draft Page 126 MRCPv2 Protocol February, 2005 The response to the QUERY-VOICEPRINT method request will contain an indication of the status of the designated voiceprint in the "Voiceprint-Exists" header field, allowing the client to determine whether to use the current voiceprint for verification, train a new voiceprint, or choose a different voiceprint. A Voiceprint is completely specified by providing a repository location and a voiceprint identifier. The particular voice-print or identity within the repository is specified by string identifier unique within the repository. The "Voiceprint-Identity" header field MUST carry this unique voiceprint identifier within a given repository. Example1: This example assumes a verification session is in progress and the voiceprint exists in the voiceprint repository. C->S: MRCP/2.0 123 QUERY-VOICEPRINT 314168 Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/voice-prints/ Voiceprint-Identifier: johnsmith.voiceprint S->C: MRCP/2.0 123 314168 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/voice-prints/ Voiceprint-Identifier: johnsmith.voiceprint Voiceprint-Exists: true Example2: This example assumes that the URI provided in the 'Repository-URI' header field is a bad URI. C->S: MRCP/2.0 123 QUERY-VOICEPRINT 314168 Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/bad-uri/ Voiceprint-Identifier: johnsmith.voiceprint S->C: MRCP/2.0 123 314168 405 COMPLETE Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/bad-uri/ Voiceprint-Identifier: johnsmith.voiceprint Completion-Cause: 007 repository-uri-failure 11.9. DELETE-VOICEPRINT The DELETE-VOICEPRINT method removes a voiceprint from a repository or speaker identification repository. This method MUST carry Repository-URI and the Voiceprint-Identifier header fields. S Shanmugham IETF-Draft Page 127 MRCPv2 Protocol February, 2005 If a voiceprint record doesn't exist, the DELETE-VOICEPRINT method can silently ignore the message and still return 200 status code. Example: This example demonstrates a message to remove a specific voiceprint. C->S: MRCP/2.0 123 DELETE-VOICEPRINT 314168 Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/bad-uri/ Voiceprint-Identifier: johnsmith.voiceprint S->C: MRCP/2.0 49 314168 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.10. VERIFY The VERIFY method is used to send the utterance's audio stream to the verification resource, which will then process it according to the current Verification-Mode, either to train/adapt the voiceprint or verify/identify the user. If the voiceprint is new or was deleted by a previous DELETE-VOICEPRINT method, the VERIFY method would train the voiceprint. If the voiceprint already exits, it is adapted and not re-trained by the VERIFY command. When both a recognizer and verification resource share the same session, the VERIFY method MUST be called prior to calling the RECOGNIZE method on the recognizer resource. In such cases, server vendors will know that verification must be enabled for a subsequent call to RECOGNIZE. Example: C->S: MRCP/2.0 49 VERIFY 543260 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 49 543260 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speakverify When the VERIFY request is done, the MRCP server should send a 'VERIFICATION-COMPLETE' event to the client. 11.11. VERIFY-FROM-BUFFER The VERIFY-FROM-BUFFER method begins an ongoing evaluation of the currently buffered audio against the voiceprint. Only one VERIFY or VERIFY-FROM-BUFFER method can be active at any one time. The buffered audio is not consumed by this evaluation operation and thus VERIFY-FROM-BUFFER may be called multiple times using different voiceprints. S Shanmugham IETF-Draft Page 128 MRCPv2 Protocol February, 2005 For VERIFY-FROM-BUFFER method, the server can optionally return an "IN-PROGRESS" response followed by the "VERIFICATION-COMPLETE" event. When the VERIFY-FROM-BUFFER method is invoked and the verification buffer is in use the server MUST return an IN-PRGORESS response and waits until the buffer is available for verify processing again. The verification buffer is owned by the verification resource but shares write access with other input resources on the same session, such as recognition and recording. Hence, it is considered to be in use, if there is a read or write operation such as, a RECORD or RECOGNIZE with the ver-buffer-utterance header field set to "true", on a resource that shares this buffer. Note that, if RECORD or RECOGNIZE command returns with a failure cause code, the VERIFY-FROM-BUFFER command waiting to process that buffer MUST also fail with a Completion-Cause of 005 (buffer-empty). Example: This example illustrates the usage of some buffering methods. In this scenario the client first performed a live verification, but the utterance is rejected. In the meantime, the utterance is also saved to the audio buffer. Then, another voiceprint is used to do verification against the audio buffer and the utterance is accepted. Here, we assume both 'num-min-verification-phrases' and 'num-max- verification-phrases' are 1. C->S: MRCP/2.0 123 START-SESSION 314161 Channel-Identifier: 32AECB23433801@speakverify Adapt-Model: true Repository-URI: http://www.example.com/voice-prints Voiceprint-Identifier: johnsmith.voiceprint S->C: MRCP/2.0 49 314161 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify C->S: MRCP/2.0 123 VERIFY 314162 Channel-Identifier: 32AECB23433801@speakverify Ver-buffer-utterance: true S->C: MRCP/2.0 49 314164 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 123 VERIFICATION-COMPLETE 314162 COMPLETE Channel-Identifier: 32AECB23433801@speakverify Completion-Cause: 000 success Content-Type: application/nlsml+xml Content-Length: 123 <?xml version="1.0"?> <result grammar="What-Grammar-URI"> <extensions> S Shanmugham IETF-Draft Page 129 MRCPv2 Protocol February, 2005 <result-type type="VERIFICATION" /> <verification-result> <voiceprint id="johnsmith"> <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> rejected </decision> <verification-score> 0.05465 </verification-score> </incremental> <cumulative> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> rejected </decision> <verification-score> 0.09664 </verification-score> </cumulative> </voiceprint> </verification-result> </extensions> </result> C->S: MRCP/2.0 123 QUERY-VOICEPRINT 314163 Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/voiceprints/ Voiceprint-Identifier: johnsmith S->C: MRCP/2.0 123 314163 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify Repository-URI: http://www.example.com/voiceprints/ Voiceprint-Identifier: johnsmith.voiceprint Voiceprint-Exists: true C->S: MRCP/2.0 123 START-SESSION 314164 Channel-Identifier: 32AECB23433801@speakverify Adapt-Model: true Repository-URI: http://www.example.com/voice-prints Voiceprint-Identifier: marysmith.voiceprint S->C: MRCP/2.0 49 314164 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify C->S: MRCP/2.0 123 VERIFY-FROM-BUFFER 314165 Channel-Identifier: 32AECB23433801@speakverify Verification-Mode: verify S->C: MRCP/2.0 49 314165 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 123 VERIFICATION-COMPLETE 314165 COMPLETE Channel-Identifier: 32AECB23433801@speakverify S Shanmugham IETF-Draft Page 130 MRCPv2 Protocol February, 2005 Completion-Cause: 000 success Content-Type: application/nlsml+xml Content-Length: 123 <?xml version="1.0"?> <result grammar="What-Grammar-URI"> <extensions> <result-type type="VERIFICATION" /> <verification-result> <voiceprint id="marysmith"> <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.98 </verification-score> </incremental> <cumulative> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.85 </verification-score> </cumulative> </voiceprint> </verification-result> </extensions> </result> C->S: MRCP/2.0 49 END-SESSION 314166 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 49 314166 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.12. VERIFY-ROLLBACK The VERIFY-ROLLBACK method discards the last buffered utterance or discards the last live utterances (when the mode is "train" or "verify"). This method should be invoked when the caller provides undesirable input such as non-speech noises, side-speech, out-of- grammar utterances, commands, etc. Note that this method does not provide a stack of rollback states. Executing VERIFY-ROLLBACK twice in succession without an intervening recognition operation has no effect on the second attempt. Example: C->S: MRCP/2.0 49 VERIFY-ROLLBACK 314165 Channel-Identifier: 32AECB23433801@speakverify S Shanmugham IETF-Draft Page 131 MRCPv2 Protocol February, 2005 S->C: MRCP/2.0 49 314165 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.13. STOP The STOP method from the client to the server tells the verification resource to stop the VERIFY or VERIFY-FROM-BUFFER request if one is active. If such a request is active and the STOP request successfully terminated it, then the response header contains an active-request-id-list header field containing the request-id of the VERIFY or VERIFY-FROM-BUFFER request that was terminated. In this case, no VERIFICATION-COMPLETE event will be sent for the terminated request. If there was no verify request active, then the response MUST NOT contain an active-request-id-list header field. Either way the response MUST contain a status of 200(Success). The STOP method can carry a "Abort-Verification" header field which specifies if the verification result until that point should be discarded or returned. If this header field is not present or if the value is "true", the verification result is discarded and STOP response does not contain any result data. If the field is present and its value is "false", the STOP_ response MUST contain a "Completion-Cause" header field and carry the Verification result data in its body. An aborted VERIFY request does an automatic roll-back and will not affect the cumulative score. A VERIFY request that was stopped with no "Abort-Verification" header field or with the "Abort- Verification" header field set to "false" will affect cumulative scores and would need to be explicitly rolled-back if it should not be considered for cumulative scores. Example: This example assumes a voiceprint identity has already been established. C->S: MRCP/2.0 123 VERIFY 314177 Channel-Identifier: 32AECB23433801@speakverify Verification-Mode: verify S->C: MRCP/2.0 49 314177 200 IN-PROGRESS Channel-Identifier: 32AECB23433801@speakverify C->S: MRCP/2.0 49 STOP 314178 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 123 314178 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify Active-Request-Id-List: 314177 S Shanmugham IETF-Draft Page 132 MRCPv2 Protocol February, 2005 11.14. START-INPUT-TIMERS This request is sent from the client to the verification resource to start the no-input timer, usually once the audio prompts to the caller have played to completion. Example: C->S: MRCP/2.0 49 START-INPUT-TIMERS 543260 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 49 543260 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.15. VERIFICATION-COMPLETE The VERIFICATION-COMPLETE event follows a call to VERIFY or VERIFY- FROM-BUFFER and is used to communicate to the client the verification results. This event will contain only verification results. Example: S->C: MRCP/2.0 123 VERIFICATION-COMPLETE 543259 COMPLETE Completion-Cause: 000 success Content-Type: application/nlsml+xml Content-Length: 123 <?xml version="1.0"?> <result grammar="What-Grammar-URI"> <extensions> <result-type type="VERIFICATION" /> <verification-result> <voiceprint id="johnsmith"> <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.85 </verification-score> </incremental> <cumulative> <num-frames> 150 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.75 </verification-score> </cumulative> </voiceprint> </verification-result> </extensions> </result> S Shanmugham IETF-Draft Page 133 MRCPv2 Protocol February, 2005 11.16. START-OF-SPEECH The START-OF-SPEECH event is returned from the server to the client once the server has detected speech. This event is always returned by the verification resource when speech has been detected, irrespective of the fact that both the recognizer and verification resource are sharing the same session or not. Example: S->C: MRCP/2.0 49 START-OF-SPEECH 543259 IN-PROGRESS Channel-Identifier: 32AECB23433801@speakverify 11.17. CLEAR-BUFFER The CLEAR-BUFFER method can be used to clear the verification buffer. This buffer is used to buffer speech during a recognition, record or verification operations that may later be used for verification from buffer. As noted before, the verification resource is shared by other input resources like, recognizers and recorders. Hence, a CLEAR-BUFFER would fail if the verification buffer is in use. This happens when any one of the input resources that shares this buffer has an active read or write operation such as RECORD, RECOGNIZE or VERIFY with the ver-buffer-utterance header field set to "true". Example: C->S: MRCP/2.0 49 CLEAR-BUFFER 543260 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 49 543260 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify 11.18. GET-INTERMEDIATE-RESULT The GET-INTERMEDIATE-RESULT method can be used to poll for intermediate results of a verification request that is in progress. This does not change the state of the resource. It just collects the verification results until that point and returns the information in the method response. The response to this method will contain only verification results. The method response MUST NOT contain a Completion-Cause header field as the request is not complete yet. If the resource does not have a verification in progress the response would have a 402 failure code and no result in the body. Example: C->S: MRCP/2.0 49 GET-INTERMEDIATE-RESULTS 543260 Channel-Identifier: 32AECB23433801@speakverify S->C: MRCP/2.0 49 543260 200 COMPLETE Channel-Identifier: 32AECB23433801@speakverify S Shanmugham IETF-Draft Page 134 MRCPv2 Protocol February, 2005 Content-Type: application/nlsml+xml Content-Length: 123 <?xml version="1.0"?> <result grammar="What-Grammar-URI"> <extensions> <result-type type="VERIFICATION" /> <verification-result> <voiceprint id="marysmith"> <incremental> <num-frames> 50 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.85 </verification-score> </incremental> <cumulative> <num-frames> 150 </num-frames> <device> cellular-phone </device> <gender> female </gender> <decision> accepted </decision> <verification-score> 0.65 </verification-score> </cumulative> </voiceprint> </verification-result> </extensions> </result> 12. Security Considerations The MRCPv2 protocol may carry sensitive information such as account numbers, passwords etc as well as use media for identification and verification purposes. For this reason it is important that the client have the option of secure communication with the server for both the control messages as well as the media, though the client is not required to use it. This is achieved by imposing following requirements on MRCPv2 server implementations. All MRCPv2 servers MUST implement digest authentication (sip:) and SHOULD implement sips: in its SIP implementation. All MRCPv2 servers must support TLS for the transport of control messages between the client and server. All MRCPv2 servers MUST support Secure Real-Time Transport Protocol (SRTP) as an option to send and receive media. 13. IANA Considerations 13.1. New registries This section describes the name spaces (registries) for MRCPv2 that IANA is requested to create and maintain. Assignment/registration S Shanmugham IETF-Draft Page 135 MRCPv2 Protocol February, 2005 policies are described in [24] and are consistent with RFC 2434 [25]. MRCPv2 resource types IANA SHALL create a new name space of "MRCPv2 resource types" with the initial values that are defined in section 4.2. All maintenance within and additions to the contents of this name space MUST be according to the "Standards Action" registration policy. MRCPv2 methods and events IANA SHALL create a new name space of "MRCPv2 methods and events" with the initial values that are defined by the "method-name" BNF in section 5.1 and the "event-name" BNF in section 5.3. All maintenance within and additions to the contents of this name space MUST be according to the "Standards Action" registration policy. MRCPv2 headers IANA SHALL create a new name space of "MRCPv2 headers" with the initial values that are defined by the "message-header" BNF in section 5. All maintenance within and additions to the contents of this name space MUST be according to the "Standards Action" registration policy. Note that the values permitted for the "Vendor-Specific-Parameters" parameter are managed according to a different policy. See "MRCPv2 vendor-specific parameters", below. MRCPv2 status codes IANA SHALL create a new name space of "MRCPv2 status codes" with the initial values that are defined in section 5.2. All maintenance within and additions to the contents of this name space MUST be according to the "Specification Required with Expert Review" registration policy. MRCPv2 vendor-specific parameters IANA SHALL create a new name space of "MRCPv2 vendor-specific parameters". All maintenance within and additions to the contents of this name space MUST be according to the "Hierarchical Allocation" registration policy as follows. Each name (corresponding to the "vendor-av-pair-name" BNF production) MUST satisfy the syntax requirements of Internet Domain Names as described in section 2.3.1 of RFC 1035 [26] (and as updated or obsoleted by successive RFCs), with one exception, the order of the domain names is reversed. For example, a vendor-specific parameter "foo" by example.com would have the form "com.example.foo". The first, or top-level domain, is restricted to exactly the set of Top- Level Internet Domains defined by IANA and will be updated by IANA S Shanmugham IETF-Draft Page 136 MRCPv2 Protocol February, 2005 when and only when that set changes. The second-level and all subdomains within the parameter name MUST be allocated according to the "Expert Review" policy. The Designated Expert MAY decide to delegate subdomains to the requestor. As a general guideline, the Designated Expert is encouraged to manage the allocation of corporate, organizational, or institutional names and delegate all subdomains accordingly. For example, the Designated Expert MAY allocate "com.example" and delegate all subdomains of that name to the organization represented by the Internet domain name "example.com". For simplicity, the Designated Expert is encouraged to perform allocations according to the existing allocations of Internet domain names to organizations, institutions, corporations, etc. 13.2. NLSML-related registrations application/nlsml+xml MIME type registration IANA is requested to register the following MIME type according to the process defined in RFC 2048 [23]. To: ietf-types@iana.org Subject: Registration of MIME media type application/nlsml+xml MIME media type name: application MIME subtype name: nlsml+xml Required parameters: Optional parameters: "charset": All of the considerations described in RFC3023 also apply to the application/nlsml+xml media type. Encoding considerations: All of the considerations described in RFC3023 also apply to the application/nlsml+xml media type. Security considerations: As with HTML, NLSML documents contain links to other data stores (grammars, verification resources, etc.). Unlike HTML, however, the data stores are not treated as media to be rendered. Nevertheless, linked files may themselves have security considerations, which would be those of the individual registered types. Additionally, this media type has all of the security considerations described in RFC 3023. Interoperability considerations: Although an NLSML document is itself a complete XML document, for a fuller interpretation of the content a receiver of an NLSML document may wish to access resources linked to by the document. The inability of an NLSML processor to access or process such linked resources could result in different behavior by the ultimate consumer of the data. S Shanmugham IETF-Draft Page 137 MRCPv2 Protocol February, 2005 Published specification: http://www.ietf.org/internet-drafts/draft- ietf-speechsc-mrcpv2-06.txt Applications which use this media type: MRCPv2 clients and servers Additional information: Magic number(s): There is no single initial byte sequence that is always present for NLSML files. Person & email address to contact for further information: Sarvi Shanmugham, sarvi@cisco.com Intended usage: This media type is expected to be used only in conjunction with MRCPv2. NLSML XML DTD registration IANA is requested to register and maintain the following XML Public ID and DTD. Information provided follows the template in RFC3688 [22]. XML element type: publicid URI: "-//IETF//DTD NLSML//EN" Registrant Contact: IESG XML: See Appendix A.2.1 "NLSML Document Type Definition". NLSML XML Schema registration IANA is requested to register and maintain the following XML Schema. Information provided follows the template in RFC3688 [22]. XML element type: schema URI: http://www.ietf.org/xml/ns/mrcpv2 Registrant Contact: IESG XML: See Appendix A.2.1 "NLSML Schema Definition". NLSML XML Name space registration IANA is requested to register and maintain the following XML Name space. Information provided follows the template in RFC3688 [22]. XML element type: ns S Shanmugham IETF-Draft Page 138 MRCPv2 Protocol February, 2005 URI: http://www.ietf.org/xml/schema/mrcpv2 Registrant Contact: IESG XML: Please provide pointer to the RFC, when approved. 13.3. session URL scheme registration IANA is requested to register the following new URI scheme. The information below follows the template given in RFC 2717 [27]. URL scheme name: "session" URL scheme syntax: The syntax of this scheme is identical to that defined for the "cid" scheme in section 2 of RFC 2392 [15]. Character encoding considerations: URL values are limited to the US-ASCII character set. Intended usage: The URL is intended to identify a data resource previously given to the network computing resource. The purpose of this scheme is to permit access to the specific resource for the lifetime of the session with the entity storing the resource. The media type of the resource CAN vary. There is no explicit mechanism for communication of the media type. Applications and/or protocols which use this URL scheme name: This scheme name will be used by MRCPv2 clients and servers. Interoperability considerations: The character set for URLs is restricted to US-ASCII. Note that none of the resources are accessible after the MCRPv2 session ends, hence the name of the scheme. For clients who establish one MRCPv2 session only for the entire speech application being implemented this is sufficient, but clients who create, terminate, and recreate MRCP sessions for performance or scalability reasons will lose access to resources established in the earlier session(s). Security considerations: The URLs defined here provide an addressing or referencing mechanism only. Given that the communication channel between client and server is secure, that the server correctly accesses the resource associated with the URL, and that the server ensures session-only lifetime and access for each URL, the only remaining security issues are those of the types of media referred to by the URL. Relevant publications: This specification, particularly sections 6.1 "Content-Id", 8.5 "Lexicon Data", 9.5 "Recognizer Grammar Data", and 9.9 "RECOGNIZE". Contact for further information: Sarvi Shanmugham, sarvi@cisco.com S Shanmugham IETF-Draft Page 139 MRCPv2 Protocol February, 2005 Author/Change controller: IESG 13.4. SDP parameter registrations IANA is requested to register the following SDP parameter values. The information for each follows the template given in RFC 2327 [6], Appendix B. "TCP/MRCPv2" value of the "proto" parameter Contact name, email address and telephone number: Sarvi Shanmugham, sarvi@cisco.com, +1.408.902.3875 Name being registered (as it will appear in SDP): TCP/MRCPv2 Long-form name in English: MCRPV2 over TCP Type of name: proto Explanation of name: This name represents the MCRPv2 protocol carried over TCP. Reference to specification of name: IANA, please include a pointer here to the current specification when approved as an RFC by the IESG. "TCP/TLS/MRCPv2" value of the "proto" parameter Contact name, email address and telephone number: Sarvi Shanmugham, sarvi@cisco.com, +1.408.902.3875 Name being registered (as it will appear in SDP): TCP/TLS/MRCPv2 Long-form name in English: MCRPV2 over TLS over TCP Type of name: proto Explanation of name: This name represents the MCRPv2 protocol carried over TLS over TCP. Reference to specification of name: IANA, please include a pointer here to the current specification when approved as an RFC by the IESG. "resource" value of the "att-field" parameter Contact name, email address and telephone number: Sarvi Shanmugham, sarvi@cisco.com, +1.408.902.3875 S Shanmugham IETF-Draft Page 140 MRCPv2 Protocol February, 2005 Attribute name (as it will appear in SDP): resource Long-form attribute name in English: MRCPv2 resource type Type of attribute: session-level Subject to charset attribute?: no Explanation of attribute: See section 4.2 description and examples Specification of appropriate attribute values: See section 13.1 "MRCPv2 resources types" "channel" value of the "att-field" parameter Contact name, email address and telephone number: Sarvi Shanmugham, sarvi@cisco.com, +1.408.902.3875 Attribute name (as it will appear in SDP): channel Long-form attribute name in English: MRCPv2 resource channel identifier Type of attribute: session-level Subject to charset attribute?: no Explanation of attribute: See section 4.2 description and examples Specification of appropriate attribute values: See section 4.2 and the "channel-id" ABNF production in this document. 14. Examples: 14.1. Message Flow The following is an example of a typical MRCPv2 session of speech synthesis and recognition between a client and a server. Opening a session to the MRCPv2 server. This is exchange does not allocate a resource or setup media. It simply establishes a SIP session with the MRCPv2 server. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE S Shanmugham IETF-Draft Page 141 MRCPv2 Protocol February, 2005 Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp Content-Length: 142 v=0 o=sarvi 2890844526 2890842807 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 S->C: SIP/2.0 200 OK To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314159 INVITE Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp Content-Length: 131 v=0 o=sarvi 2890844526 2890842807 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 C->S: ACK sip:mrcp@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mrcp@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314160 ACK Content-Length: 0 The client requests the server to create synthesizer resource control channel to do speech synthesis. This also adds a media pipe to send the generated speech. Note that in this example, the client request the reuse of an existing MRCPv2 TCP pipe between the client and the server. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314161 INVITE Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp Content-Length: 142 S Shanmugham IETF-Draft Page 142 MRCPv2 Protocol February, 2005 v=0 o=sarvi 2890844526 2890842808 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 m=application 9 TCP/MRCPv2 a=setup:active a=connection:existing a=resource:speechsynth a=cmid:1 m=audio 49170 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=recvonly a=mid:1 S->C: SIP/2.0 200 OK To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314161 INVITE Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp Content-Length: 131 v=0 o=sarvi 2890844526 2890842808 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 m=application 32416 TCP/MRCPv2 a=setup:passive a=connection:existing a=channel:32AECB23433802@speechsynth a=cmid:1 m=audio 48260 RTP/AVP 0 a=rtpmap:0 pcmu/8000 a=sendonly a=mid:1 C->S: ACK sip:mrcp@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mrcp@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314162 ACK Content-Length: 0 S Shanmugham IETF-Draft Page 143 MRCPv2 Protocol February, 2005 This exchange allocates an additional resource control channel for a recognizer. Since a recognizer would need to receive an audio stream for recognition, this interaction also updates the audio stream to sendrecv making it a 2-way audio stream. C->S: INVITE sip:mresources@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314163 INVITE Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp Content-Length: 142 v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 m=application 9 TCP/MRCPv2 a=setup:active a=connection:existing a=resource:speechsynth a=cmid:1 m=audio 49170 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=recvonly a=mid:1 m=application 9 TCP/MRCPv2 a=setup:active a=connection:existing a=resource:speechrecog a=cmid:2 m=audio 49180 RTP/AVP 0 96 a=rtpmap:0 pcmu/8000 a=rtpmap:96 telephone-event/8000 a=fmtp:96 0-15 a=sendonly a=mid:2 S->C: SIP/2.0 200 OK To: MediaServer <sip:mresources@mediaserver.com> From: sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314163 INVITE Contact: <sip: sarvi@cisco.com> Content-Type: application/sdp S Shanmugham IETF-Draft Page 144 MRCPv2 Protocol February, 2005 Content-Length: 131 v=0 o=sarvi 2890844526 2890842809 IN IP4 126.16.64.4 s=SDP Seminar i=A session for processing media c=IN IP4 224.2.17.12/127 m=application 32416 TCP/MRCPv2 a=channel:32AECB23433801@speechsynth a=cmid:1 m=audio 48260 RTP/AVP 0 a=rtpmap:0 pcmu/8000 a=sendonly a=mid:1 m=application 32416 TCP/MRCPv2 a=channel:32AECB23433802@speechrecog a=cmid:2 m=audio 48260 RTP/AVP 0 a=rtpmap:0 pcmu/8000 a=rtpmap:96 telephone-event/8000 a=fmtp:96 0-15 a=recvonly a=mid:2 C->S: ACK sip:mrcp@mediaserver.com SIP/2.0 Max-Forwards: 6 To: MediaServer <sip:mrcp@mediaserver.com>;tag=a6c85cf From: Sarvi <sip:sarvi@cisco.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 314164 ACK Content-Length: 0 A MRCPv2 SPEAK request initiates speech. C->S: MRCP/2.0 386 SPEAK 543257 Channel-Identifier: 32AECB23433802@speechsynth Kill-On-Barge-In: false Voice-gender: neutral Voice-category: teenager Prosody-volume: medium Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> S Shanmugham IETF-Draft Page 145 MRCPv2 Protocol February, 2005 <p> <s>You have 4 new messages.</s> <s>The first is from Stephanie Williams <mark name="Stephanie"/> and arrived at <break/> <say-as interpret-as="vxml:time">0345p</say-as>.</s> <s>The subject is <prosody rate="-20%">ski trip</prosody></s> </p> </speak> S->C: MRCP/2.0 49 543257 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth The synthesizer hits the special marker in the message to be spoken and faithfully informs the client of the event. S->C: MRCP/2.0 46 SPEECH-MARKER 543257 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth Speech-Marker: Stephanie The synthesizer finishes with the SPEAK request. S->C: MRCP/2.0 48 SPEAK-COMPLETE 543257 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth The recognizer is issued a request to listen for the customer choices. C->S:MRCP/2.0 343 RECOGNIZE 543258 Channel-Identifier: 32AECB23433801@speechrecog Content-Type: application/srgs+xml Content-Length: 104 <?xml version="1.0"?> <!-- the default grammar language is US English --> <grammar xml:lang="en-US" version="1.0"> <!-- single language attachment to a rule expansion --> <rule id="request"> Can I speak to <one-of xml:lang="fr-CA"> <item>Michel Tremblay</item> <item>Andre Roy</item> </one-of> </rule> </grammar> S->C: MRCP/2.0 49 543258 200 IN-PROGRESS S Shanmugham IETF-Draft Page 146 MRCPv2 Protocol February, 2005 Channel-Identifier: 32AECB23433801@speechrecog The client issues the next MRCPv2 SPEAK method. It is generally RECOMMENDED when playing a prompt to the user with kill-on-barge-in and asking for input, that the client issue the RECOGNIZE request ahead of the SPEAK request for optimum performance and user experience. This way, it is guaranteed that the recognizer is online before the prompt starts playing and the user's speech will not be truncated at the beginning (especially for power users). C->S: MRCP/2.0 289 SPEAK 543259 Channel-Identifier: 32AECB23433802@speechsynth Kill-On-Barge-In: true Content-Type: application/ssml+xml Content-Length: 104 <?xml version="1.0"?> <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/10/synthesis http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US"> <p> <s>Welcome to ABC corporation.</s> <s>Who would you like Talk to.</s> </p> </speak> S->C: MRCP/2.0 52 543259 200 IN-PROGRESS Channel-Identifier: 32AECB23433802@speechsynth Since the last SPEAK request had Kill-On-Barge-In set to "true", the speech synthesizer is interrupted when the user starts speaking. And the client is notified. Now, since the recognition and synthesizer resources are on the same session, they may have worked with each other to deliver kill-on- barge-in. Whether the synthesizer and recognizer are in the same session or not the recognizer MUST generate the START-OF-SPEECH event to the client. The client MUST then blindly turn around and issued a BARGE-IN- OCCURRED method to the synthesizer resource(if a SPEAK request was active). The synthesizer, if kill-on-barge-in was enabled on the current SPEAK request, would have then interrupted it and issued a SPEAK-COMPLETE event to the client. The completion-cause code differentiates if this is normal completion or a kill-on-barge-in interruption. S Shanmugham IETF-Draft Page 147 MRCPv2 Protocol February, 2005 S->C: MRCP/2.0 49 START-OF-SPEECH 543258 IN-PROGRESS Channel-Identifier: 32AECB23433801@speechrecog Proxy-Sync-Id: 987654321 C->S: MRCP/2.0 69 BARGE-IN-OCCURRED 543259 Channel-Identifier: 32AECB23433802@speechsynth Proxy-Sync-Id: 987654321 S->C: MRCP/2.0 72 543259 200 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Active-Request-Id-List: 543258 S->C: MRCP/2.0 73 SPEAK-COMPLETE 543259 COMPLETE Channel-Identifier: 32AECB23433802@speechsynth Completion-Cause: 001 barge-in The recognition resource matched the spoken stream to a grammar and generated results. The result of the recognition is returned by the server as part of the RECOGNITION-COMPLETE event. S->C: MRCP/2.0 412 RECOGNITION-COMPLETE 543258 COMPLETE Channel-Identifier: 32AECB23433801@speechrecog Completion-Cause: 000 success Waveform-URI: http://web.media.com/session123/audio.wav Content-Type: application/nlsml+xml Content-Length: 104 <?xml version="1.0"?> <result grammar="session:request1@form-level.store"> <interpretation> <instance name="Person"> <Person> <Name> Andre Roy </Name> </Person> </instance> <input> may I speak to Andre Roy </input> </interpretation> </result> When the client wants to tear down the whole session and all its resources, it MUST issue a SIP BYE to close the SIP session. This will de-allocate all the control channels and resources allocated under the session. C->S:BYE sip:mrcp@mediaserver.com SIP/2.0 Max-Forwards: 6 From: Sarvi <sip:sarvi@cisco.com>;tag=a6c85cf To: MediaServer <sip:mrcp@mediaserver.com>;tag=1928301774 Call-ID: a84b4c76e66710 CSeq: 231 BYE S Shanmugham IETF-Draft Page 148 MRCPv2 Protocol February, 2005 Content-Length: 0 14.2. Recognition Result Examples Simple ASR Ambiguity System: To which city will you be traveling? User: I want to go to Pittsburgh. <result grammar="http://flight"> <interpretation confidence="0.6"> <instance> <airline> <to_city>Pittsburgh</to_city> <airline> <instance> <input mode="speech"> I want to go to Pittsburgh </input> </interpretation> <interpretation confidence="0.4" <instance> <airline> <to_city>Stockholm</to_city> </airline> </instance> <input>I want to go to Stockholm</input> </interpretation> </result> Mixed Initiative: System: What would you like? User: I would like 2 pizzas, one with pepperoni and cheese, one with sausage and a bottle of coke, to go. This representation includes an order object which in turn contains objects named "food_item", "drink_item" and "delivery_method". This representation assumes there are no ambiguities in the speech or natural language processing. Note that this representation also assumes some level of intrasentential anaphora resolution, i.e., to resolve the two "one's" as "pizza". <result grammar="http://foodorder"> <interpretation confidence="1.0" > <instance> <order> <food_item confidence="1.0"> <pizza> <ingredients confidence="1.0"> pepperoni S Shanmugham IETF-Draft Page 149 MRCPv2 Protocol February, 2005 </ingredients> <ingredients confidence="1.0"> cheese </ingredients> </pizza> <pizza> <ingredients>sausage</ingredients> </pizza> </food_item> <drink_item confidence="1.0"> <size>2-liter</size> </drink_item> <delivery_method>to go</delivery_method> </order> </instance> <input mode="speech">I would like 2 pizzas, one with pepperoni and cheese, one with sausage and a bottle of coke, to go. </input> </interpretation> </result> DTMF Input A combination of dtmf input and speech would be represented using nested input elements. For example: User: My pin is (dtmf 1 2 3 4) <input> <input mode="speech" confidence ="1.0" timestamp-start="2000-04-03T0:00:00" timestamp-end="2000-04-03T0:00:01.5">My pin is </input> <input mode="dtmf" confidence ="1.0" timestamp-start="2000-04-03T0:00:01.5" timestamp-end="2000-04-03T0:00:02.0">1 2 3 4 </input> </input> Note that grammars that recognize mixtures of speech and DTMF are not currently possible in VoiceXML; however this representation may be needed for other applications of NLSML, and it may be introduced in future versions of VoiceXML. Interpreting Meta-Dialog and Meta-Task Utterances The natural language requires that the semantics specification must be capable of representing a number of types of meta-dialog and meta-task utterances (Task-Specific Information/Meta-task Information Requirements 1-8 and Generic Information about the S Shanmugham IETF-Draft Page 150 MRCPv2 Protocol February, 2005 Communication Process Requirements 1-6). This specification is flexible enough so that meta utterances can be represented on an application-specific basis without defining specific formats in this specification. Here are two examples of how meta-task and meta-dialog utterances might be represented. System: What toppings do you want on your pizza? User: What toppings do you have? <interpretation grammar="http://toppings"> <instance> <question> <questioned_item>toppings<questioned_item> <questioned_property> availability </questioned_property> </question> </instance> <input mode="speech"> what toppings do you have? </input> </interpretation> User: slow down. <interpretation grammar="http://generalCommandsGrammar"> <instance> <command> <action>reduce speech rate</action> <doer>system</doer> </command> </instance> <input mode="speech">slow down</input> </interpretation> Anaphora and Deixis This specification can be used on an application-specific basis to represent utterances that contain unresolved anaphoric and deictic references. Anaphoric references, which include pronouns and definite noun phrases that refer to something that was mentioned in the preceding linguistic context, and deictic references, which refer to something that is present in the non-linguistic context, present similar problems in that there may not be sufficient unambiguous linguistic context to determine what their exact role in the interpretation should be. In order to represent unresolved anaphora and deixis using this specification, one strategy would be for the developer to define a more surface-oriented representation that leaves the specific details of the interpretation of the S Shanmugham IETF-Draft Page 151 MRCPv2 Protocol February, 2005 reference open. (This assumes that a later component is responsible for actually resolving the reference) Example: (ignoring the issue of representing the input from the pointing gesture.) System: What do you want to drink? User: I want this (clicks on picture of large root beer.) <result> <interpretation> <instance> <doer>I</doer> <action>want</action> <object>this</object> </instance> <input mode="speech">I want this</input> </interpretation> </result> Future versions of the W3C Speech Interface Framework may address issues of representing resolved anaphora. Distinguishing Individual Items from Sets with One Member For programming convenience, it is useful to be able to distinguish between individual items and sets containing one item in the XML representation of semantic results. For example, a pizza order might consist of exactly one pizza, but a pizza might contain zero or more toppings. Since there is no standard way of marking this distinction directly in XML, in the current framework, the developer is free to adopt any conventions that would convey this information in the XML markup. One strategy would be for the developer to wrap the set of items in a grouping element, as in the following example. <order> <pizza> <topping-group> <topping>mushrooms</topping> </topping-group> </pizza> <drink>coke</drink> </order> In this example, the programmer can assume that there is supposed to be exactly one pizza and one drink in the order, but the fact that there is only one topping is an accident of this particular pizza order. S Shanmugham IETF-Draft Page 152 MRCPv2 Protocol February, 2005 If a data model is used this distinction can be made in the data model by stating that the value of the "maxOccurs" attribute can be greater than 1. Extensibility One of the natural language requirements states that the specification must be extensible. The specification supports this requirement because of its flexibility, as discussed in the discussions of meta utterances and anaphora. NLSML can easily be used in sophisticated systems to convey application-specific information that more basic systems would not make use of, for example defining speech acts. Defining standard representations for items such as dates, times, etc. could also be done. Normative Reference [1] Fielding, R., Gettys, J., Mogul, J., Frystyk. H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext transfer protocol -- HTTP/1.1", RFC 2616, June 1999. [2] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time Streaming Protocol (RTSP)", RFC 2326, April 1998 [3] Crocker, D. and P. Overell, "Augmented BNF for syntax specifications: ABNF", RFC 2234, November 1997. [4] Rosenberg, J., Schulzrinne, H., Schooler, E., Camarillo, G., Johnston, A. Peterson, J., Sparks, R., Handley, M., Schooler, E., "SIP: Session Initiation Protocol", RFC 3261, June 2002. [6] Handley, M. and V. Jacobson, "SDP: session description protocol", RFC 2327, April 1998. [7] World Wide Web Consortium, "Voice Extensible Markup Language (VoiceXML) Version 2.0", W3C Recommendation, March 2004. [8] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES", RFC 822, August 1982. [9] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [10] World Wide Web Consortium, "Speech Synthesis Markup Language (SSML) Version 1.0", W3C Recommendation, September 2004. [11] World Wide Web Consortium, "Speech Recognition Grammar Specification Version 1.0", W3C Recommendation, March 2004. S Shanmugham IETF-Draft Page 153 MRCPv2 Protocol February, 2005 [12] Bradner, S., "The Internet Standards Process - Revision 3", RFC 2026, October 1996 [13] Yergeau, F., "UTF-8, a transformation format of Unicode and ISO 10646", RFC 2044, October 1996 [14] Freed, N., Borenstein, N., "Multipupose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996 [15] Levinson, E., "Content-ID and Message-ID Uniform Resource Locators", RFC 2392, August 1998 [16] Schulzrinne, H., Petrack, S., "RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals", RFC 2833, May 2000 [17] Alvestrand, H., "Tags for the Identification of Languages", RFC 3066, January 2001 [18] Camarillo, G., Eriksson, G., Holler, J., "Grouping of Media Lines in the Session Description Protocol (SDP) ", RFC 3388, December 2002 [19] T. Bray et al., "Namespaces in XML", W3C Recommendation, 14 January 1999. [20] Yon, D., Camarillo, G., "Connection-Oriented Media Transport in the Session Description Protocol (SDP)", draft-ietf- mmusic-sdp-comedia-09.txt, (work in progress), September 2004. [21] Lenox, J., "Connection-Oriented Media Transport over the Transport Layer Security(TLS) Protocol in the Session Description Protocol (SDP)", (work in progress), draft-ietf- mmusic-comedia-tls-02.txt [22] Mealling, M., "The IETF XML Registry", RFC 3688, January 2004. [23] Freed, N., Klensin, J., and Postel, J., "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, November 1996. [24] Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs", (work in progress), http://www.ietf.org/internet-drafts/draft-narten-iana- considerations-rfc2434bis-01.txt. [25] Narten, T. and Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, October 1998. S Shanmugham IETF-Draft Page 154 MRCPv2 Protocol February, 2005 [26] Mockapetris, P., "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION", RFC 1035, November 1987. [27] Petke, R. and King, I., "Registration Procedures for URL Scheme Names", RFC 2717, November 1999. Appendix A.1 ABNF Message Definitions LWS = [*WSP CRLF] 1*WSP ; linear whitespace SWS = [LWS] ; sep whitespace UTF8-NONASCII = %xC0-DF 1UTF8-CONT / %xE0-EF 2UTF8-CONT / %xF0-F7 3UTF8-CONT / %xF8-Fb 4UTF8-CONT / %xFC-FD 5UTF8-CONT UTF8-CONT = %x80-BF VCHAR = %x21-7E param = *pchar quoted-string = SWS DQUOTE *(qdtext / quoted-pair ) DQUOTE qdtext = LWS / %x21 / %x23-5B / %x5D-7E / UTF8-NONASCII quoted-pair = "\" (%x00-09 / %x0B-0C / %x0E-7F) token = 1*(alphanum / "-" / "." / "!" / "%" / "*" / "_" / "+" / "`" / "'" / "~" ) reserved = ";" / "/" / "?" / ":" / "@" / "&" / "=" / "+" / "$" / "," mark = "-" / "_" / "." / "!" / "~" / "*" / "'" / "(" / ")" unreserved = alphanum / mark pchar = unreserved / escaped / ":" / "@" / "&" / "=" / "+" / "$" / "," alphanum = ALPHA / DIGIT S Shanmugham IETF-Draft Page 155 MRCPv2 Protocol February, 2005 escaped = "%" HEXDIG HEXDIG fragment = *uric uri = [ absoluteURI / relativeURI ] [ "#" fragment ] absoluteURI = scheme ":" ( hier-part / opaque-part ) relativeURI = ( net-path / abs-path / rel-path ) [ "?" query ] hier-part = ( net-path / abs-path ) [ "?" query ] net-path = "//" authority [ abs-path ] abs-path = "/" path-segments rel-path = rel-segment [ abs-path ] rel-segment = 1*( unreserved / escaped / ";" / "@" / "&" / "=" / "+" / "$" / "," ) opaque-part = uric-no-slash *uric uric = reserved / unreserved / escaped uric-no-slash = unreserved / escaped / ";" / "?" / ":" / "@" / "&" / "=" / "+" / "$" / "," path-segments = segment *( "/" segment ) segment = *pchar *( ";" param ) scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." ) authority = srvr / reg-name srvr = [ [ userinfo "@" ] hostport ] reg-name = 1*( unreserved / escaped / "$" / "," / ";" / ":" / "@" / "&" / "=" / "+" ) query = *uric userinfo = ( user ) [ ":" password ] "@" user = 1*( unreserved / escaped / user-unreserved ) user-unreserved = "&" / "=" / "+" / "$" / "," / ";" S Shanmugham IETF-Draft Page 156 MRCPv2 Protocol February, 2005 / "?" / "/" password = *( unreserved / escaped / "&" / "=" / "+" / "$" / "," ) hostport = host [ ":" port ] host = hostname / IPv4address / IPv6reference hostname = *( domainlabel "." ) toplabel [ "." ] domainlabel = alphanum / alphanum *( alphanum / "-" ) alphanum toplabel = ALPHA / ALPHA *( alphanum / "-" ) alphanum IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT IPv6reference = "[" IPv6address "]" IPv6address = hexpart [ ":" IPv4address ] hexpart = hexseq / hexseq "::" [ hexseq ] / "::" [ hexseq ] hexseq = hex4 *( ":" hex4) hex4 = 1*4HEXDIG port = 1*DIGIT cmid-attribute = "a=cmid:" identification-tag identification-tag = token generic-message = start-line message-header CRLF [ message-body ] message-body = *OCTET start-line = request-line / status-line / event-line request-line = mrcp-version SP message-length SP method-name SP request-id CRLF status-line = mrcp-version SP message-length SP request-id SP status-code SP request-state CRLF S Shanmugham IETF-Draft Page 157 MRCPv2 Protocol February, 2005 event-line = mrcp-version SP message-length SP event-name SP request-id SP request-state CRLF method-name = generic-method / synthesizer-method / recorder-method / recognizer-method / verifier-method generic-method = "SET-PARAMS" / "GET-PARAMS" request-state = "COMPLETE" / "IN-PROGRESS" / "PENDING" event-name = synthesizer-event / recognizer-event / recorder-event / verifier-event message-header = 1*(generic-header / resource-header) resource-header = recognizer-header / synthesizer-header / recorder-header / verifier-header generic-header = channel-identifier / active-request-id-list / proxy-sync-id / content-id / content-type / content-length / content-base / content-location / content-encoding / cache-control / logging-tag / vendor-specific ; -- content-id is as defined in RFC 2111, RFC2046 and RFC822 mrcp-version = "MRCP" "/" 1*DIGIT "." 1*DIGIT request-id = 1*DIGIT status-code = 1*DIGIT channel-identifier = "Channel-Identifier" ":" S Shanmugham IETF-Draft Page 158 MRCPv2 Protocol February, 2005 channel-id CRLF channel-id = 1*HEXDIG "@" 1*VCHAR active-request-id-list = "Active-Request-Id-List" ":" request-id *("," request-id) CRLF proxy-sync-id = "Proxy-Sync-Id" ":" 1*VCHAR CRLF content-length = "Content-Length" ":" 1*DIGIT CRLF content-base = "Content-Base" ":" absoluteURI CRLF content-type = "Content-Type" ":" media-type-value media-type-value = type "/" subtype *( ";" parameter ) type = token subtype = token parameter = attribute "=" value attribute = token value = token / quoted-string content-encoding = "Content-Encoding" ":" *WSP content-coding *(*WSP "," *WSP content-coding *WSP ) CRLF content-coding = token content-location = "Content-Location" ":" ( absoluteURI / relativeURI ) CRLF cache-control = "Cache-Control" ":" [*WSP cache-directive *( *WSP "," *WSP cache-directive *WSP )] CRLF cache-directive = "max-age" "=" delta-seconds / "max-stale" "=" [ delta-seconds ] / "min-fresh" "=" delta-seconds logging-tag = "Logging-Tag" ":" 1*VCHAR CRLF vendor-specific = "Vendor-Specific-Parameters" ":" [vendor-specific-av-pair S Shanmugham IETF-Draft Page 159 MRCPv2 Protocol February, 2005 *[";" vendor-specific-av-pair]] CRLF vendor-specific-av-pair = vendor-av-pair-name "=" vendor-av-pair-value vendor-av-pair-name = 1*VCHAR vendor-av-pair-value = 1*VCHAR set-cookie = "Set-Cookie:" cookies CRLF cookies = cookie *("," *LWS cookie) cookie = attribute "=" value *(";" cookie-av) cookie-av = "Comment" "=" value / "Domain" "=" value / "Max-Age" "=" value / "Path" "=" value / "Secure" / "Version" "=" 1*DIGIT / "Age" "=" delta-seconds set-cookie2 = "Set-Cookie2:" cookies2 CRLF cookies2 = cookie2 *("," *LWS cookie2) cookie2 = attribute "=" value *(";" cookie-av2) cookie-av2 = "Comment" "=" value / "CommentURL" "=" DQUOTE uri DQUOTE / "Discard" / "Domain" "=" value / "Max-Age" "=" value / "Path" "=" value / "Port" [ "=" DQUOTE portlist DQUOTE ] / "Secure" / "Version" "=" 1*DIGIT / "Age" "=" delta-seconds portlist = portnum *("," *LWS portnum) portnum = 1*DIGIT ; Synthesizer ABNF synthesizer-method = "SPEAK" / "STOP" / "PAUSE" / "RESUME" / "BARGE-IN-OCCURRED" S Shanmugham IETF-Draft Page 160 MRCPv2 Protocol February, 2005 / "CONTROL" synthesizer-event = "SPEECH-MARKER" / "SPEAK-COMPLETE" synthesizer-header = jump-size / kill-on-barge-in / speaker-profile / completion-cause / completion-reason / voice-parameter / prosody-parameter / speech-marker / speech-language / fetch-hint / audio-fetch-hint / fetch-timeout / failed-uri / failed-uri-cause / speak-restart / speak-length / load-lexicon / lexicon-search-order jump-size = "Jump-Size" ":" speech-length-value CRLF speech-length-value = numeric-speech-length / text-speech-length text-speech-length = 1*ALPHA SP "Tag" numeric-speech-length = ("+" / "-") 1*DIGIT SP numeric-speech-unit numeric-speech-unit = "Second" / "Word" / "Sentence" / "Paragraph" delta-seconds = 1*DIGIT kill-on-barge-in = "Kill-On-Barge-In" ":" boolean-value CRLF boolean-value = "true" / "false" speaker-profile = "Speaker-Profile" ":" absoluteURI CRLF completion-cause = "Completion-Cause" ":" 1*DIGIT SP S Shanmugham IETF-Draft Page 161 MRCPv2 Protocol February, 2005 1*VCHAR CRLF completion-reason = "Completion-Reason" ":" quoted-string CRLF voice-parameter = "Voice-" voice-param-name ":" [voice-param-value] CRLF voice-param-name = 1*VCHAR voice-param-value = 1*VCHAR prosody-parameter = "Prosody-" prosody-param-name ":" [prosody-param-value] CRLF prosody-param-name = 1*VCHAR prosody-param-value = 1*VCHAR timestamp = "Timestamp" "=" time-stamp-value CRLF speech-marker = "Speech-Marker" ":" 1*VCHAR [";" timestamp ] CRLF speech-language = "Speech-Language" ":" [1*VCHAR] CRLF fetch-hint = "Fetch-Hint" ":" [1*ALPHA] CRLF audio-fetch-hint = "Audio-Fetch-Hint" ":" [1*ALPHA] CRLF fetch-timeout = "Fetch-Timeout" ":" [1*DIGIT] CRLF failed-uri = "Failed-URI" ":" absoluteURI CRLF failed-uri-cause = "Failed-URI-Cause" ":" 1*alphanum CRLF speak-restart = "Speak-Restart" ":" boolean-value CRLF speak-length = "Speak-Length" ":" speech-length-value CRLF load-lexicon = "Load-Lexicon" ":" boolean CRLF lexicon-search-order = "Lexicon-Search-Order" ":" absoluteURI *[";" absoluteURI] CRLF ; Recognizer ABNF recognizer-method = recog-only-method / enrollment-method S Shanmugham IETF-Draft Page 162 MRCPv2 Protocol February, 2005 recog-only-method = "DEFINE-GRAMMAR" / "RECOGNIZE" / "INTERPRET" / "GET-RESULT" / "START-INPUT-TIMERS" / "STOP" enrollment-method = "START-PHRASE-ENROLLMENT" / "ENROLLMENT-ROLLBACK" / "END-PHRASE-ENROLLMENT" / "MODIFY-PHRASE" / "DELETE-PHRASE" recognizer-event = "START-OF-SPEECH" / "RECOGNITION-COMPLETE" / "INTERPRETATION-COMPLETE" recognizer-header = recog-only-header / enrollment-header recog-only-header = confidence-threshold / sensitivity-level / speed-vs-accuracy / n-best-list-length / no-input-timeout / recognition-timeout / waveform-uri / input-waveform-uri / completion-cause / completion-reason / recognizer-context-block / start-input-timers / speech-complete-timeout / speech-incomplete-timeout / dtmf-interdigit-timeout / dtmf-term-timeout / dtmf-term-char / fetch-timeout / failed-uri / failed-uri-cause / save-waveform / new-audio-channel / speech-language / ver-buffer-utterance / recognition-mode / cancel-if-queue / hotword-max-duration / hotword-min-duration / interpret-text / one-of-rule-id-uri S Shanmugham IETF-Draft Page 163 MRCPv2 Protocol February, 2005 enrollment-header = num-min-consistent-pronunciations / consistency-threshold / clash-threshold / personal-grammar-uri / phrase-id / phrase-nl / weight / save-best-waveform / new-phrase-id / confusable-phrases-uri / abort-phrase-enrollment confidence-threshold = "Confidence-Threshold" ":" [1*DIGIT] CRLF sensitivity-level = "Sensitivity-Level" ":" [1*DIGIT] CRLF speed-vs-accuracy = "Speed-Vs-Accuracy" ":" [1*DIGIT] CRLF n-best-list-length = "N-Best-List-Length" ":" [1*DIGIT] CRLF no-input-timeout = "No-Input-Timeout" ":" [1*DIGIT] CRLF recognition-timeout = "Recognition-Timeout" ":" [1*DIGIT] CRLF waveform-uri = "Waveform-URI" ":" absoluteURI CRLF recognizer-context-block = "Recognizer-Context-Block" ":" [1*VCHAR] CRLF start-input-timers = "Start-Input-Timers" ":" boolean-value CRLF speech-complete-timeout = "Speech-Complete-Timeout" ":" [1*DIGIT] CRLF speech-incomplete-timeout = "Speech-Incomplete-Timeout" ":" [1*DIGIT] CRLF dtmf-interdigit-timeout = "DTMF-Interdigit-Timeout" ":" [1*DIGIT] CRLF dtmf-term-timeout = "DTMF-Term-Timeout" ":" [1*DIGIT] CRLF S Shanmugham IETF-Draft Page 164 MRCPv2 Protocol February, 2005 dtmf-term-char = "DTMF-Term-Char" ":" [VCHAR] CRLF fetch-timeout = "Fetch-Timeout" ":" [1*DIGIT] CRLF save-waveform = "Save-Waveform" ":" [boolean-value] CRLF new-audio-channel = "New-Audio-Channel" ":" boolean-value CRLF one-of-rule-id-uri = "One-Of-Rule-Id-URI" ":" token CRLF recognition-mode = "Recognition-Mode" ":" 1*ALPHA CRLF cancel-if-queue = "Cancel-If-Queue" ":" boolean-value CRLF hotword-max-duration = "Hotword-Max-Duration" ":" 1*DIGIT CRLF hotword-min-duration = "Hotword-Min-Duration" ":" 1*DIGIT CRLF num-min-consistent-pronunciations = "Num-Min-Consistent-Pronunciations" ":" 1*DIGIT CRLF consistency-threshold = "Consistency-Threshold" ":" 1*DIGIT CRLF clash-threshold = "Clash-Threshold" ":" 1*DIGIT CRLF personal-grammar-uri = "Personal-Grammar-URI" ":" uri CRLF phrase-id = "Phrase-ID" ":" 1*VCHAR CRLF phrase-nl = "Phrase-NL" ":" 1*VCHAR CRLF weight = "Weight" ":" weight-value CRLF weight-value = 1*DIGIT save-best-waveform = "Save-Best-Waveform" ":" boolean-value CRLF new-phrase-id = "New-Phrase-ID" ":" 1*VCHAR CRLF confusable-phrases-uri = "Confusable-Phrases-URI" ":" uri CRLF abort-phrase-enrollment = "Abort-Phrase-Enrollment" ":" boolean-value CRLF S Shanmugham IETF-Draft Page 165 MRCPv2 Protocol February, 2005 ; Verifier ABNF verifier-method = "START-SESSION" / "END-SESSION" / "QUERY-VOICEPRINT" / "DELETE-VOICEPRINT" / "VERIFY" / "VERIFY-FROM-BUFFER" / "VERIFY-ROLLBACK" / "STOP" / "START-INPUT-TIMERS" verifier-event = "VERIFICATION-COMPLETE" / "START-OF-SPEECH" verifier-header = repository-uri / voiceprint-identifier / verification-mode / adapt-model / abort-model / security-level / num-min-verification-phrases / num-max-verification-phrases / no-input-timeout / save-waveform / waveform-uri / voiceprint-exists / ver-buffer-utterance / input-waveform-uri / completion-cause / completion-reason / speech-complete-timeout / new-audio-channel / abort-verification / start-input-timers repository-uri = "Respository-URI" ":" uri CRLF voiceprint-identifier = "Voiceprint-Identifier" ":" 1*VCHAR "." 3VCHAR [";" 1*VCHAR "." 3VCHAR] CRLF verification-mode = "Verification-Mode" ":" verification-mode-string S Shanmugham IETF-Draft Page 166 MRCPv2 Protocol February, 2005 verification-mode-string = "train" / "verify" adapt-model = "Adapt-Model" ":" boolean-value CRLF abort-model = "Abort-Model" ":" boolean-value CRLF security-level = "Security-Level" ":" security-level-string CRLF security-level-string = "high" / "medium-high" / "medium" / "medium-low" / "low" num-min-verification-phrases = "Num-Min-Verification-Phrases" ":" 1*DIGIT CRLF num-max-verification-phrases = "Num-Max-Verification-Phrases" ":" 1*DIGIT CRLF voiceprint-exists = "Voiceprint-Exists" ":" boolean-value CRLF ver-buffer-utterance = "Ver-Buffer-Utterance" ":" boolean-value CRLF input-waveform-uri = "Input-Waveform-URI" ":" uri CRLF abort-verification = "Abort-Verification " ":" boolean-value CRLF ; Recorder ABNF recorder-method = "RECORD" / "STOP" recorder-event = "START-OF-SPEECH" / "RECORD-COMPLETE" recorder-header = sensitivity-level / no-input-timeout / completion-cause / completion-reason / failed-uri / failed-uri-cause / record-uri S Shanmugham IETF-Draft Page 167 MRCPv2 Protocol February, 2005 / media-type / max-time / final-silence / capture-on-speech / new-audio-channel / start-input-timers record-uri = "Record-URI" ":" uri CRLF media-type = "Media-Type" ":" media-type-value CRLF max-time = "Max-Time" ":" 1*DIGIT CRLF final-silence = "Final-Silence" ":" 1*DIGIT CRLF capture-on-speech = "Capture-On-Speech " ":" 1*DIGIT CRLF A.2 XML Schema and DTD A.2.1 Recognition Results NLSML Schema Definition <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.ietf.org/xml/schema/mrcpv2" xmlns="http://www.ietf.org/xml/ns/mrcpv2" elementFormDefault="qualified" attributeFormDefault="unqualified" > <xs:element name="result"> <xs:annotation> <xs:documentation> Natural Language Semantic Markup Schema </xs:documentation> </xs:annotation> <xs:complexType> <xs:sequence> <xs:element name="interpretation" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="instance" minOccurs="0"> <xs:complexType> <xs:sequence> <xs:any/> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="input"> <xs:complexType mixed="true"> S Shanmugham IETF-Draft Page 168 MRCPv2 Protocol February, 2005 <xs:choice> <xs:element name="noinput" minOccurs="0"/> <xs:element name="nomatch" minOccurs="0"/> <xs:element name="input" minOccurs="0"/> </xs:choice> <xs:attribute name="confidence" type="confidenceinfo" default="1.0"/> <xs:attribute name="timestamp-start" type="xs:string"/> <xs:attribute name="timestamp-end" type="xs:string"/> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="confidence" type="confidenceinfo" default="1.0"/> <xs:attribute name="grammar" type="xs:anyURI" use="optional"/> <xs:attribute name="x-model" type="xs:anyURI" use="optional"/> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="grammar" type="xs:anyURI" use="optional"/> <xs:attribute name="x-model" type="xs:anyURI" use="optional"/> </xs:complexType> </xs:element> <xs:simpleType name="confidenceinfo"> <xs:restriction base="xs:float"> <xs:minInclusive value="0.0"/> <xs:maxInclusive value="1.0"/> </xs:restriction> </xs:simpleType> </xs:schema> NLSML Document Type Definition <!-- NLSML Results DTD --> <!ELEMENT result (interpretation*)> <!ATTLIST result grammar CDATA #IMPLIED x-model CDATA #IMPLIED > <!ELEMENT interpretation (instance,input?)> <!ATTLIST interpretation S Shanmugham IETF-Draft Page 169 MRCPv2 Protocol February, 2005 confidence CDATA "1.0" grammar CDATA #IMPLIED x-model CDATA #IMPLIED > <!ELEMENT input (#PCDATA|noinput|nomatch|input)*> <!ATTLIST input mode (dtmf | speech) "speech" timestamp-start CDATA #IMPLIED timestamp-end CDATA #IMPLIED confidence CDATA "1.0" > <!ELEMENT nomatch (#PCDATA)*> <!ELEMENT noinput EMPTY> <!ELEMENT instance (#PCDATA|EMPTY)*> A.2.2 Enrollment Results Enrollment Results Schema Definition <!-- MRCP Enrollment Schema (See http://www.oasis-open.org/committees/relax-ng/spec.html) --> <element name="enrollment-result" datatypeLibrary="http://www.w3.org/2001/XMLSchema- datatypes" ns="" xmlns="http://relaxng.org/ns/structure/1.0"> <interleave> <element name="num-clashes"> <data type="nonNegativeInteger"/> </element> <element name="num-good-repetitions"> <data type="nonNegativeInteger"/> </element> <element name="num-repetitions-still-needed"> <data type="nonNegativeInteger"/> </element> <element name="consistency-status"> <choice> <value>CONSISTENT</value> <value>INCONSISTENT</value> <value>UNDECIDED</value> </choice> </element> <optional> <element name="clash-phrase-ids"> <oneOrMore> <element name="item"> <data type="token"/> </element> </oneOrMore> </element> S Shanmugham IETF-Draft Page 170 MRCPv2 Protocol February, 2005 </optional> <optional> <element name="transcriptions"> <oneOrMore> <element name="item"> <text/> </element> </oneOrMore> </element> </optional> <optional> <element name="confusable-phrases"> <oneOrMore> <element name="item"> <text/> </element> </oneOrMore> </element> </optional> </interleave> </element> Enrollment Results Document Type Definition <!-- MRCP Enrollment Results DTD --> <!ELEMENT enrollment-result (num-clashes, num-good-repetitions,num-repetitions-still-needed, consistency-status, clash-phrase-ids?, transcriptions?, confusable-phrases?)> <!ELEMENT num-clashes (#PCDATA)> <!ELEMENT num-good-repetitions (#PCDATA)> <!ELEMENT num-repetitions-still-needed (#PCDATA)> <!ELEMENT consistency-status (#PCDATA)> <!ELEMENT clash-phrase-ids (item)> <!ELEMENT transcriptions (item)> <!ELEMENT confusable-phrases (item)> <!ELEMENT item (#PCDATA)> A.2.3 Verification Results Verification Results Schema Definition <!-- MRCP Verification Results Schema (See http://www.oasis-open.org/committees/relax-ng/spec.html) --> <grammar datatypeLibrary="http://www.w3.org/2001/XMLSchema- datatypes" ns="" xmlns="http://relaxng.org/ns/structure/1.0"> S Shanmugham IETF-Draft Page 171 MRCPv2 Protocol February, 2005 <start> <element name="verification-result"> <element name="num-frames"> <ref name="num-framesContent"/> </element> <element name="voiceprint"> <ref name="firstVoiceprintContent"/> </element> <zeroOrMore> <element name="voiceprint"> <ref name="restVoiceprintContent"/> </element> </zeroOrMore> </element> </start> <define name="firstVoiceprintContent"> <attribute name="id"> <data type="string"/> </attribute> <interleave> <optional> <element name="adapted"> <data type="boolean"/> </element> <element name="needmoredata"> <ref name="needmoredataContent"/> </element> </optional> <element name="incremental"> <ref name="firstCommonContent"/> </element> <element name="cumulative"> <ref name="firstCommonContent"/> </element> </interleave> </define> <define name="restVoiceprintContent"> <attribute name="id"> <data type="string"/> </attribute> <interleave> <optional> <element name="incremental"> <ref name="restCommonContent"/> </element> </optional> <element name="cumulative"> <ref name="restCommonContent"/> </element> S Shanmugham IETF-Draft Page 172 MRCPv2 Protocol February, 2005 </interleave> </define> <define name="firstCommonContent"> <interleave> <choice> <element name="decision"> <ref name="decisionContent"/> </element> </choice> <element name="device"> <ref name="deviceContent"/> </element> <element name="gender"> <ref name="genderContent"/> </element> <zeroOrMore> <element name="verification-score"> <ref name="verification-scoreContent"/> </element> </zeroOrMore> </interleave> </define> <define name="restCommonContent"> <interleave> <optional> <element name="decision"> <ref name="decisionContent"/> </element> </optional> <optional> <element name="utterance-length"> <ref name="utterance-lengthContent"/> </element> </optional> <optional> <element name="device"> <ref name="deviceContent"/> </element> </optional> <optional> <element name="gender"> <ref name="genderContent"/> </element> </optional> <zeroOrMore> <element name="verification-score"> <ref name="verification-scoreContent"/> </element> </zeroOrMore> S Shanmugham IETF-Draft Page 173 MRCPv2 Protocol February, 2005 </interleave> </define> <define name="decisionContent"> <choice> <value>accepted</value> <value>rejected</value> <value>undecided</value> </choice> </define> <define name="needmoredataContent"> <data type="boolean"/> </define> <define name="utterance-lengthContent"> <data type="nonNegativeInteger"/> </define> <define name="deviceContent"> <choice> <value>cellular-phone</value> <value>electret-phone</value> <value>carbon-button-phone</value> <value>unknown</value> </choice> </define> <define name="genderContent"> <choice> <value>male</value> <value>female</value> <value>unknown</value> </choice> </define> <define name="verification-scoreContent"> <data type="float"> <param name="minInclusive">0</param> <param name="maxInclusive">1</param> </data> </define> </grammar> Verification Results Document Type Definition <!-- MRCP Verification Results DTD --> <!ELEMENT verification-result (voiceprint+)> <!ELEMENT voiceprint (adapted?, incremental?, cumulative)> S Shanmugham IETF-Draft Page 174 MRCPv2 Protocol February, 2005 <!ATTLIST voiceprint id CDATA #REQUIRED> <!ELEMENT incremental ((decision | needmoredata)?, num-frames?, device?, gender?, verification-score)> <!ELEMENT cumulative ((decision | needmoredata)?, num-frames?, device?, gender?, verification-score)> <!ELEMENT decision (#PCDATA)> <!ELEMENT needmoredata (#PCDATA)> <!ELEMENT num-frames (#PCDATA)> <!ELEMENT device (#PCDATA)> <!ELEMENT gender (#PCDATA)> <!ELEMENT adapted (#PCDATA)> <!ELEMENT verification-score (#PCDATA)> Full Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. S Shanmugham IETF-Draft Page 175 MRCPv2 Protocol February, 2005 Contributors Daniel C. Burnett Nuance Communications 1005 Hamilton Court Menlo Park, CA 94025-1422 USA Email: burnett@nuance.com Pierre Forgues Nuance Communications Ltd. 111 Duke Street Suite 4100 Montreal, Quebec Canada H3C 2M1 Email: forgues@nuance.com Charles Galles Intervoice, Inc. 17811 Waterview Parkway Dallas, Texas 75252 Email: charles.galles@intervoice.com Klaus Reifenrath Scansoft, Inc Guldensporenpark 32 Building D 9820 Merelbeke Belgium Email: klaus.reifenrath@scansoft.com Acknowledgements Andre Gillet (Nuance Communications) Andrew Hunt (ScanSoft) Aaron Kneiss (ScanSoft) Brian Eberman (ScanSoft) Corey Stohs (Cisco Systems Inc) Dan Burnett (Nuance Communications) Jeff Kusnitz (IBM Corp) Ganesh N Ramaswamy (IBM Corp) Klaus Reifenrath (ScanSoft) Kristian Finlator (ScanSoft) Martin Dragomirecky (Cisco Systems Inc) Peter Monaco (Nuance Communications) Pierre Forgues (Nuance Communications) S Shanmugham IETF-Draft Page 176 MRCPv2 Protocol February, 2005 Ran Zilca (IBM Corp) Suresh Kaliannan (Cisco Systems Inc.) Skip Cave (Intervoice Inc) Magnus Westerlun (Ericsson) Thomas Gal (LumenVox) Dave Burke (VoxPilot) Paolo Baggia (Loquendo) Editors' Addresses Saravanan Shanmugham Cisco Systems Inc. 170 W Tasman Drive, San Jose, CA 95134 Email: sarvi@cisco.com Daniel C. Burnett Nuance Communications 1380 Willow Road Menlo Park, CA 94025 Email: burnett@nuance.com S Shanmugham IETF-Draft Page 177
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