An XML Schema for the CLUE data model
draft-ietf-clue-data-model-schema-05

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Last updated 2014-06-19
Replaces draft-presta-clue-data-model-schema
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CLUE Working Group                                             R. Presta
Internet-Draft                                               S P. Romano
Intended status: Informational                      University of Napoli
Expires: December 21, 2014                                 June 19, 2014

                 An XML Schema for the CLUE data model
                  draft-ietf-clue-data-model-schema-05

Abstract

   This document formally describes the data model adopted in CLUE.  It
   provides an XML schema file for the definition of CLUE data model
   types.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 21, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.

Table of Contents

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   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  <mediaCaptures>  . . . . . . . . . . . . . . . . . . . . . . . 17
   5.  <encodingGroups> . . . . . . . . . . . . . . . . . . . . . . . 17
   6.  <captureScenes>  . . . . . . . . . . . . . . . . . . . . . . . 17
   7.  <simultaneousSets> . . . . . . . . . . . . . . . . . . . . . . 17
   8.  <globalSceneEntries> . . . . . . . . . . . . . . . . . . . . . 17
   9.  <captureEncodings> . . . . . . . . . . . . . . . . . . . . . . 17
   10. <mediaCapture> . . . . . . . . . . . . . . . . . . . . . . . . 17
     10.1.  <capturedMedia> . . . . . . . . . . . . . . . . . . . . . 20
     10.2.  <captureSceneIDREF> . . . . . . . . . . . . . . . . . . . 20
     10.3.  <encGroupIDREF> . . . . . . . . . . . . . . . . . . . . . 20
     10.4.  <spatialInformation>  . . . . . . . . . . . . . . . . . . 20
       10.4.1.  <capturePoint>  . . . . . . . . . . . . . . . . . . . 21
       10.4.2.  <captureArea> . . . . . . . . . . . . . . . . . . . . 22
     10.5.  <nonSpatiallyDefinable> . . . . . . . . . . . . . . . . . 23
     10.6.  <content> . . . . . . . . . . . . . . . . . . . . . . . . 23
     10.7.  <synchronizationID> . . . . . . . . . . . . . . . . . . . 24
     10.8.  <composed>  . . . . . . . . . . . . . . . . . . . . . . . 24
     10.9.  <switched>  . . . . . . . . . . . . . . . . . . . . . . . 24
     10.10. <policy>  . . . . . . . . . . . . . . . . . . . . . . . . 24
     10.11. <maxCaptures> . . . . . . . . . . . . . . . . . . . . . . 25
     10.12. <individual>  . . . . . . . . . . . . . . . . . . . . . . 25
     10.13. <description> . . . . . . . . . . . . . . . . . . . . . . 25
     10.14. <priority>  . . . . . . . . . . . . . . . . . . . . . . . 26
     10.15. <lang>  . . . . . . . . . . . . . . . . . . . . . . . . . 26
     10.16. <mobility>  . . . . . . . . . . . . . . . . . . . . . . . 26
     10.17. <maxCaptureEncodings> . . . . . . . . . . . . . . . . . . 26
     10.18. <relatedTo> . . . . . . . . . . . . . . . . . . . . . . . 26
     10.19. <view>  . . . . . . . . . . . . . . . . . . . . . . . . . 26
     10.20. <presentation>  . . . . . . . . . . . . . . . . . . . . . 27
     10.21. <capturedPeople>  . . . . . . . . . . . . . . . . . . . . 27
       10.21.1. <personIDREF> . . . . . . . . . . . . . . . . . . . . 27
     10.22. captureID attribute . . . . . . . . . . . . . . . . . . . 27
   11. Audio captures . . . . . . . . . . . . . . . . . . . . . . . . 27
     11.1.  <audioChannelFormat>  . . . . . . . . . . . . . . . . . . 28
   12. Video captures . . . . . . . . . . . . . . . . . . . . . . . . 28
     12.1.  <embeddedText>  . . . . . . . . . . . . . . . . . . . . . 29
   13. Text captures  . . . . . . . . . . . . . . . . . . . . . . . . 29
   14. <captureScene> . . . . . . . . . . . . . . . . . . . . . . . . 29
     14.1.  <sceneInformation>  . . . . . . . . . . . . . . . . . . . 30
     14.2.  <sceneEntries>  . . . . . . . . . . . . . . . . . . . . . 30
     14.3.  sceneID attribute . . . . . . . . . . . . . . . . . . . . 31
     14.4.  scale attribute . . . . . . . . . . . . . . . . . . . . . 31
   15. <sceneEntry> . . . . . . . . . . . . . . . . . . . . . . . . . 32
     15.1.  <mediaCaptureIDs> . . . . . . . . . . . . . . . . . . . . 32
     15.2.  sceneEntryID attribute  . . . . . . . . . . . . . . . . . 33

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     15.3.  mediaType attribute . . . . . . . . . . . . . . . . . . . 33
   16. <encodingGroup>  . . . . . . . . . . . . . . . . . . . . . . . 33
     16.1.  <maxGroupBandwidth> . . . . . . . . . . . . . . . . . . . 33
     16.2.  <encodingIDList>  . . . . . . . . . . . . . . . . . . . . 33
     16.3.  encodingGroupID attribute . . . . . . . . . . . . . . . . 34
   17. <simultaneousSet>  . . . . . . . . . . . . . . . . . . . . . . 34
     17.1.  <captureIDREF>  . . . . . . . . . . . . . . . . . . . . . 34
     17.2.  <sceneEntryIDREF> . . . . . . . . . . . . . . . . . . . . 35
   18. <globalSceneEntry> . . . . . . . . . . . . . . . . . . . . . . 35
   19. <people> . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
     19.1.  <person>  . . . . . . . . . . . . . . . . . . . . . . . . 36
       19.1.1.  personID attribute  . . . . . . . . . . . . . . . . . 37
       19.1.2.  <personInfo>  . . . . . . . . . . . . . . . . . . . . 37
       19.1.3.  <personType>  . . . . . . . . . . . . . . . . . . . . 37
   20. <captureEncoding>  . . . . . . . . . . . . . . . . . . . . . . 37
     20.1.  <captureID> . . . . . . . . . . . . . . . . . . . . . . . 38
     20.2.  <encodingID>  . . . . . . . . . . . . . . . . . . . . . . 38
     20.3.  <configuredContent> . . . . . . . . . . . . . . . . . . . 38
   21. <clueInfo> . . . . . . . . . . . . . . . . . . . . . . . . . . 38
   22. Sample XML file  . . . . . . . . . . . . . . . . . . . . . . . 39
   23. MCC example  . . . . . . . . . . . . . . . . . . . . . . . . . 45
   24. Diff with  draft-ietf-clue-data-model-schema-02 version  . . . 52
   25. Diff with draft-ietf-clue-data-model-schema-03 version . . . . 52
   26. Diff with draft-ietf-clue-data-model-schema-04 version . . . . 53
   27. Informative References . . . . . . . . . . . . . . . . . . . . 53

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1.  Introduction

   This document formally describes the data model associated with the
   description of a CLUE telepresence session.  It defines the involved
   data model types and provides a formal description of each of them in
   terms of an XML schema file.

   The schema is based on information contained in
   [I-D.ietf-clue-framework].  It encodes information and constraints
   defined in the aforementioned document in order to provide a formal
   representation of the concepts therein presented.  The schema
   definition is intended to be modified according to changes applied to
   the above mentioned CLUE document.

   The document actually represents a proposal aiming at the definition
   of a coherent structure for all the information associated with the
   description of a telepresence scenario.

2.  Terminology

   This document refers to the same terminology used in
   [I-D.ietf-clue-framework].  We briefly recall herein some of the main
   terms adopted in that document.

   Audio Capture:  Media Capture for audio.  Denoted as ACn in the
      example cases in this document.

   Camera-Left and Right:  For Media Captures, Camera-Left and Camera-
      Right are from the point of view of a person observing the
      rendered media.  They are the opposite of Stage-Left and Stage-
      Right.

   Capture:  Same as Media Capture.

   Capture Device:  A device that converts audio and video input into an
      electrical signal, in most cases to be fed into a media encoder.

   Capture Encoding:  A specific encoding of a Media Capture, to be sent
      by a Media Provider to a Media Consumer via RTP.

   Capture Scene:  An abstraction grouping semantically-coupled Media
      Captures available at the Media Provider's side, representing a
      precise portion of the local scene that can be transmitted
      remotely.  Capture Scene MAY correspond to a part of the
      telepresence room or MAY focus only on the presentation media.  A
      Capture Scene is characterized by a set of attributes, as well as
      by a set of Capture Scene Entries.

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   Capture Scene Entry:  A list of Media Captures of the same media type
      that constitute a possible representation of a Capture Scene.
      Media Captures belonging to the same Capture Scene Entry can be
      sent simultaneously by the Media Provider.

   CLUE Participant:  An entity able to use the CLUE protocol within a
      telepresence session.  It can be an Endpoint or a MCU able to use
      the CLUE protocol.

   Consumer:  Same as Media Consumer.

   Encoding or Individual Encoding:  The representation of an encoding
      technology.  In the CLUE datamodel, for each encoding, a set of
      parameters is provided.  Such parameters represent encoding
      constraints, like for example the maximum bandwidth of the Media
      Provider the encoding can consume.

   Encoding Group:  The representation of a group of encodings.  For
      each group, a set of parameters is provided, representing the
      constraints to be applied to the group as a whole.  An example is
      the maximum bandwidth that can be consumed when using the
      contained encodings simultaneously.

   Endpoint  The logical point of final termination through receiving,
      decoding and rendering, and/or initiation through capturing,
      encoding, and sending of media streams.  An endpoint consists of
      one or more physical devices which source and sink media streams,
      and exactly one SIP Conferencing Framework Participant (which, in
      turn, includes exactly one SIP User Agent).  Endpoints can be
      anything from multiscreen/multicamera room controllers to handheld
      devices.

   MCU:  Multipoint Control Unit (MCU) - a device that connects two or
      more endpoints together into one single multimedia conference.  An
      MCU may include a Mixer.

   Media:  Any data that, after suitable encoding, can be conveyed over
      RTP, including audio, video or timed text.

   Media Capture:  A "Media Capture", or simply "Capture", is a source
      of Media of a single type (i.e., audio or video or text).

   Media Stream:  The term "Media Stream", or simply "Stream", is used
      as a synonymous of Capture Encoding.

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   Media Provider:  A CLUE participant (i.e., an Endpoint or an MCU)
      able to send Media Streams.

   Media Consumer:  A CLUE participant (i.e., an Endpoint or an MCU)
      able to receive Media Streams.

   Scene:  Same as Capture Scene.

   Scene Entry:  Same as Capture Scene Entry.

   Stream:  Same as Media Stream.

   Multiple Content Capture:  A Capture that can contain different Media
      Captures of the same media type.  It is denoted as MCC in this
      document.  In the Stream resulting from the MCC, the Stream coming
      from the encoding of the composing Media Captures can appear
      simultaneously, if the MCC is the result of a mixing operation, or
      can appear alternatively over time, according to a certain
      switching policy.

   Plane of Interest:  The spatial plane containing the most relevant
      subject matter.

   Provider:  Same as Media Provider.

   Render:   The process of reproducing the received Streams like, for
      instance, displaying the remote video on the Media Consumer's
      screens, or playing out the remote audio through loudspeakers.

   Simultaneous Transmission Set:  A set of Media Captures that can be
      transmitted simultaneously from a Media Provider.

   Single Media Capture:  A Capture representing the Media coming from a
      single-source Capture Device.

   Spatial Information:  Data about the spatial position of a Capture
      Device that generates a Single Media Capture within the context of
      a Capture Scene representing a physical portion of a Telepresence
      Room.

   Stream Characteristics:  The union of the features used to describe a
      Stream in the CLUE environment and in the SIP-SDP environment

   Video Capture:  A Media Capture for video.

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3.  XML Schema

   This section contains the proposed CLUE data model schema definition.

   The element and attribute definitions are formal representations of
   the concepts needed to describe the capabilities of a Media Provider,
   as well as the streams that are requested by a Media Consumer given
   the Provider's offer.

   The main groups of information are:

      <mediaCaptures>: the list of media captures available (Section 4)

      <encodingGroups>: the list of encoding groups (Section 5)

      <captureScenes>: the list of capture scenes (Section 6)

      <simultaneousSets>: the list of simultaneous transmission sets
      (Section 7)

      <globalSceneEntries>: the list of global capture entry sets
      (Section 8)

      <people>: meta data about the participants represented in the
      telepresence session (Section 19). [to be discussed]

      <captureEncodings>: the list of instantiated capture encodings
      (Section 9)

   All of the above refers to concepts that have been introduced in
   [I-D.ietf-clue-framework] and further detailed in the following of
   this document.

<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema
   targetNamespace="urn:ietf:params:xml:ns:clue-info"
   xmlns:tns="urn:ietf:params:xml:ns:clue-info"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   xmlns="urn:ietf:params:xml:ns:clue-info"
   xmlns:xcard="urn:ietf:params:xml:ns:vcard-4.0"
   elementFormDefault="qualified"
   attributeFormDefault="unqualified">

<!-- Import xcard XML schema -->
<xs:import namespace="urn:ietf:params:xml:ns:vcard-4.0"
schemaLocation="xcard.xsd"/>

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<!-- ELEMENT DEFINITIONS -->
<xs:element name="mediaCaptures" type="mediaCapturesType"/>
<xs:element name="encodingGroups" type="encodingGroupsType"/>
<xs:element name="captureScenes" type="captureScenesType"/>
<xs:element name="simultaneousSets" type="simultaneousSetsType"/>
<xs:element name="globalSceneEntries" type="globalSceneEntriesType"/>
<xs:element name="people" type="peopleType"/>

<xs:element name="captureEncodings" type="captureEncodingsType"/>

<!-- MEDIA CAPTURES TYPE -->
<!-- envelope of media captures -->
<xs:complexType name="mediaCapturesType">
 <xs:sequence>
   <xs:element name="mediaCapture" type="mediaCaptureType"
   maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- DESCRIPTION element -->
<xs:element name="description">
 <xs:complexType>
  <xs:simpleContent>
   <xs:extension base="xs:string">
     <xs:attribute name="lang" type="xs:language"/>
   </xs:extension>
  </xs:simpleContent>
 </xs:complexType>
</xs:element>

<!-- MEDIA CAPTURE TYPE -->
<xs:complexType name="mediaCaptureType" abstract="true">
  <xs:sequence>
    <!-- mandatory fields -->
    <xs:element name="capturedMedia" type="xs:string"/>
    <xs:element name="captureSceneIDREF" type="xs:IDREF"/>
    <xs:element name="encGroupIDREF" type="xs:IDREF" minOccurs="0"/>
    <xs:choice>
      <xs:sequence>
        <xs:element name="spatialInformation"
                    type="tns:spatialInformationType"/>
      </xs:sequence>
      <xs:element name="nonSpatiallyDefinable" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- for handling multi-content captures: -->
    <xs:choice>

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      <xs:sequence>
        <xs:element name="synchronizationID" type="xs:ID" minOccurs="0"/>
        <xs:element name="content" type="contentType" minOccurs="0"/>
        <xs:element name="composed" type="xs:boolean" minOccurs="0"/>
        <xs:element name="switched" type="xs:boolean" minOccurs="0"/>
        <xs:element name="policy" type="xs:string" minOccurs="0"/>
        <xs:element name="maxCaptures" type="xs:unsignedInt" minOccurs="0"/>
      </xs:sequence>
      <xs:element name="individual" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- optional fields -->
    <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="priority" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="lang" type="xs:language" minOccurs="0"/>
    <xs:element name="mobility" type="mobilityType" minOccurs="0"/>
    <xs:element name="presentation" type="presentationType" minOccurs="0"/>
    <xs:element name="view" type="viewType" minOccurs="0"/>
    <xs:element name="capturedPeople" type="capturedPeopleType" minOccurs="0"/>
    <xs:element name="maxCaptureEncodings" type="xs:unsignedInt"
    minOccurs="0"/>
    <xs:element name="relatedTo" type="xs:IDREF" minOccurs="0"/>
    <xs:any namespace="##other" processContents="lax" minOccurs="0"
    maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="captureID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- CONTENT TYPE -->
<xs:complexType name="contentType">
 <xs:sequence>
   <xs:element name="captureIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>
   <xs:element name="sceneEntryIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>
   <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- CAPTURED PEOPLE TYPE -->
<xs:complexType name="capturedPeopleType">
<xs:sequence>
<xs:element name="personIDREF" type="xs:IDREF" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>

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<!-- PEOPLE TYPE -->
<xs:complexType name="peopleType">
<xs:sequence>
<xs:element name="person" type="personType"
                    maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>

<!-- PERSON TYPE -->
<xs:complexType name="personType">
  <xs:sequence>
     <xs:element name="personInfo" type="xcard:vcardType" maxOccurs="1"
                         minOccurs="0"/>
     <xs:element name="personType" type="personTypeType"
                         minOccurs="0"
                 maxOccurs="unbounded"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
                 maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="personID" type="xs:ID"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- PERSON TYPE TYPE -->
<xs:simpleType name="personTypeType">
        <xs:restriction base="xs:string">
        <xs:enumeration value="chairman"/>
        <xs:enumeration value="vice-chairman"/>
        <xs:enumeration value="minute taker"/>
        <xs:enumeration value="presenter"/>
        <xs:enumeration value="translator"/>
        <xs:enumeration value="timekeeper"/>
        <xs:enumeration value="attendee"/>
        </xs:restriction>
</xs:simpleType>

<!-- VIEW TYPE -->
<xs:simpleType name="viewType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="room"/>
  <xs:enumeration value="table"/>
  <xs:enumeration value="lectern"/>
  <xs:enumeration value="individual"/>
  <xs:enumeration value="audience"/>
 </xs:restriction>
</xs:simpleType>

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<!-- PRESENTATION TYPE -->
<xs:simpleType name="presentationType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="slides"/>
  <xs:enumeration value="image"/>
  <xs:enumeration value=""/>
 </xs:restriction>
</xs:simpleType>

<!-- SPATIAL INFORMATION TYPE -->
<xs:complexType name="spatialInformationType">
 <xs:sequence>
  <xs:element name="capturePoint" type="capturePointType"/>
  <xs:element name="captureArea" type="captureAreaType"
  minOccurs="0"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- MOBILITY TYPE -->
<xs:simpleType name="mobilityType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="static"/>
  <xs:enumeration value="dynamic"/>
  <xs:enumeration value="highly-dynamic"/>
 </xs:restriction>
</xs:simpleType>

<!-- TEXT CAPTURE TYPE -->
<xs:complexType name="textCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- AUDIO CAPTURE TYPE -->
<xs:complexType name="audioCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
   <xs:sequence>
    <xs:element name="audioChannelFormat" type="audioChannelFormatType"
    minOccurs="0"/>
   </xs:sequence>
  </xs:extension>

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 </xs:complexContent>
</xs:complexType>

<!-- AUDIO CHANNEL FORMAT TYPE -->
<xs:simpleType name="audioChannelFormatType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="mono"/>
  <xs:enumeration value="stereo"/>
 </xs:restriction>
</xs:simpleType>

<!-- VIDEO CAPTURE TYPE -->
<xs:complexType name="videoCaptureType">
 <xs:complexContent>
  <xs:extension base="tns:mediaCaptureType">
   <xs:sequence>
    <xs:element ref="embeddedText" minOccurs="0"/>
   </xs:sequence>
  </xs:extension>
 </xs:complexContent>
</xs:complexType>

<!-- EMBEDDED TEXT ELEMENT -->
<xs:element name="embeddedText">
 <xs:complexType>
  <xs:simpleContent>
   <xs:extension base="xs:boolean">
    <xs:attribute name="lang" type="xs:language"/>
   </xs:extension>
  </xs:simpleContent>
 </xs:complexType>
</xs:element>

<!-- CAPTURE SCENES TYPE -->
<!-- envelope of capture scenes -->
<xs:complexType name="captureScenesType">
 <xs:sequence>
  <xs:element name="captureScene" type="captureSceneType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE SCENE TYPE -->
<xs:complexType name="captureSceneType">
 <xs:sequence>
  <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
  <xs:element name="sceneInformation" type="xcard:vcardType" minOccurs="0"/>

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  <xs:element name="sceneEntries" type="sceneEntriesType"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="sceneID" type="xs:ID" use="required"/>
 <xs:attribute name="scale" type="scaleType" use="required"/>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

<!-- SCALE TYPE -->
<xs:simpleType name="scaleType">
 <xs:restriction base="xs:string">
  <xs:enumeration value="millimeters"/>
  <xs:enumeration value="unknown"/>
  <xs:enumeration value="noscale"/>
 </xs:restriction>
</xs:simpleType>

<!-- CAPTURE AREA TYPE -->
<xs:complexType name="captureAreaType">
 <xs:sequence>
  <xs:element name="bottomLeft" type="pointType"/>
  <xs:element name="bottomRight" type="pointType"/>
  <xs:element name="topLeft" type="pointType"/>
  <xs:element name="topRight" type="pointType"/>
 </xs:sequence>
</xs:complexType>

<!-- POINT TYPE -->
<xs:complexType name="pointType">
 <xs:sequence>
  <xs:element name="x" type="xs:decimal"/>
  <xs:element name="y" type="xs:decimal"/>
  <xs:element name="z" type="xs:decimal"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE POINT TYPE -->
<xs:complexType name="capturePointType">
 <xs:complexContent>
  <xs:extension base="pointType">
   <xs:sequence>
    <xs:element name="lineOfCapturePoint" type="tns:pointType"
    minOccurs="0"/>
   </xs:sequence>
   <xs:attribute name="pointID" type="xs:ID"/>
  </xs:extension>
 </xs:complexContent>

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</xs:complexType>

<!-- SCENE ENTRIES TYPE -->
<!-- envelope of scene entries of a capture scene -->
<xs:complexType name="sceneEntriesType">
 <xs:sequence>
  <xs:element name="sceneEntry" type="sceneEntryType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- SCENE ENTRY TYPE -->
<xs:complexType name="sceneEntryType">
 <xs:sequence>
  <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
  <xs:element name="mediaCaptureIDs" type="captureIDListType"/>
 </xs:sequence>
 <xs:attribute name="sceneEntryID" type="xs:ID" use="required"/>
 <xs:attribute name="mediaType" type="xs:string" use="required"/>
</xs:complexType>

<!-- CAPTURE ID LIST TYPE -->
<xs:complexType name="captureIDListType">
 <xs:sequence>
  <xs:element name="captureIDREF" type="xs:IDREF"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- ENCODING GROUPS TYPE -->
<xs:complexType name="encodingGroupsType">
 <xs:sequence>
  <xs:element name="encodingGroup" type="tns:encodingGroupType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- ENCODING GROUP TYPE -->
<xs:complexType name="encodingGroupType">
 <xs:sequence>
  <xs:element name="maxGroupBandwidth" type="xs:unsignedInt"/>
  <xs:element name="encodingIDList" type="encodingIDListType"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="encodingGroupID" type="xs:ID" use="required"/>

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 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- ENCODING ID LIST TYPE -->
<xs:complexType name="encodingIDListType">
 <xs:sequence>
  <xs:element name="encID" type="xs:string" maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- SIMULTANEOUS SETS TYPE -->
<xs:complexType name="simultaneousSetsType">
 <xs:sequence>
  <xs:element name="simultaneousSet" type="simultaneousSetType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- SIMULTANEOUS SET TYPE -->
<xs:complexType name="simultaneousSetType">
 <xs:sequence>
   <xs:element name="captureIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>
   <xs:element name="sceneEntryIDREF" type="xs:IDREF"
   minOccurs="0" maxOccurs="unbounded"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="setID" type="xs:ID" use="required"/>
 <xs:attribute name="mediaType" type="xs:string"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- GLOBAL SCENE ENTRIES TYPE -->
<xs:complexType name="globalSceneEntriesType">
 <xs:sequence>
  <xs:element name="globalSceneEntry" type="globalSceneEntryType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- GLOBAL SCENE ENTRY TYPE -->
<xs:complexType name="globalSceneEntryType">
 <xs:sequence>
   <xs:element name="sceneEntryIDREF" type="xs:IDREF"
    maxOccurs="unbounded"/>
   <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>

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 </xs:sequence>
 <xs:attribute name="globalSceneEntryID" type="xs:ID"/>
 <xs:attribute name="mediaType" type="xs:string" use="required"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- CAPTURE ENCODINGS TYPE -->
<xs:complexType name="captureEncodingsType">
 <xs:sequence>
  <xs:element name="captureEncoding" type="captureEncodingType"
  maxOccurs="unbounded"/>
 </xs:sequence>
</xs:complexType>

<!-- CAPTURE ENCODING TYPE -->
<xs:complexType name="captureEncodingType">
 <xs:sequence>
  <xs:element name="captureID" type="xs:string"/>
  <xs:element name="encodingID" type="xs:string"/>
  <xs:element name="configuredContent" type="contentType" minOccurs="0"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="ID" type="xs:ID"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

<!-- CLUE INFO ELEMENT -->
<!-- the <clueInfo> envelope can be seen
     as the ancestor of an <advertisement> envelope -->
<xs:element name="clueInfo" type="clueInfoType"/>

<!-- CLUE INFO TYPE -->
<xs:complexType name="clueInfoType">
  <xs:sequence>
   <xs:element ref="mediaCaptures"/>
   <xs:element ref="encodingGroups"/>
   <xs:element ref="captureScenes"/>
   <xs:element ref="simultaneousSets" minOccurs="0"/>
   <xs:element ref="globalSceneEntries" minOccurs="0"/>
   <xs:element ref="people" minOccurs="0"/>
   <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="clueInfoID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
</xs:schema>

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   The following sections describe the XML schema in more detail.

4.  <mediaCaptures>

   <mediaCaptures> represents the list of one ore more media captures
   available on the media provider's side.  Each media capture is
   represented by a <mediaCapture> element (Section 10).

5.  <encodingGroups>

   <encodingGroups> represents the list of the encoding groups available
   at the media provider's side.  Each encoding group is represented by
   an <encodingGroup> element (Section 16).

6.  <captureScenes>

   <captureScenes> represents the list of capture scenes available at
   the media provider's side.  Each capture scene is represented by a
   <captureScene> element.  (Section 14).

7.  <simultaneousSets>

   <simultaneousSets> contains the simultaneous sets indicated by the
   media provider.  Each simultaneous set is represented by a
   <simultaneousSet> element.  (Section 17).

8.  <globalSceneEntries>

   <globalSceneEntries> contains a set of alternative representations of
   all the scenes that are offered by a Media Provider to a Media
   Consumer.  Each alternative is named "global scene entry" and is
   represented by a <globalSceneEntry> element.  (Section 18).

9.  <captureEncodings>

   <captureEncodings> is a list of capture encodings.  It can represent
   either the list of the desired capture encodings indicated by the
   media consumer or the list of instantiated captures on the provider's
   side.  Each capture encoding is represented by a <captureEncoding>
   element.  (Section 20).

10.  <mediaCapture>

   According to the CLUE framework, a media capture is the fundamental
   representation of a media flow that is available at the provider's
   side.  Media captures are characterized (i) by a set of features that
   are independent from the specific type of medium, and (ii) by a set
   of features that are media-specific.  The features that are common to

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   all media types appear within the media capture type, that has been
   designed as an abstract complex type.  Media-specific captures, such
   as video captures, audio captures and others, are specializations of
   that abstract media capture type, as in a typical generalization-
   specialization hierarchy.

   The following is the XML Schema definition of the media capture type:

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<!-- MEDIA CAPTURE TYPE -->
<xs:complexType name="mediaCaptureType" abstract="true">
  <xs:sequence>
    <!-- mandatory fields -->
    <xs:element name="capturedMedia" type="xs:string"/>
    <xs:element name="captureSceneIDREF" type="xs:IDREF"/>
    <xs:element name="encGroupIDREF" type="xs:IDREF" minOccurs="0"/>
    <xs:choice>
      <xs:sequence>
        <xs:element name="spatialInformation"
                    type="tns:spatialInformationType"/>
      </xs:sequence>
      <xs:element name="nonSpatiallyDefinable" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- for handling multi-content captures: -->
    <xs:choice>
      <xs:sequence>
        <xs:element name="synchronizationID" type="xs:ID" minOccurs="0"/>
        <xs:element name="content" type="contentType" minOccurs="0"/>
        <xs:element name="composed" type="xs:boolean" minOccurs="0"/>
        <xs:element name="switched" type="xs:boolean" minOccurs="0"/>
        <xs:element name="policy" type="xs:string" minOccurs="0"/>
        <xs:element name="maxCaptures" type="xs:unsignedInt" minOccurs="0"/>
      </xs:sequence>
      <xs:element name="individual" type="xs:boolean" fixed="true"/>
    </xs:choice>
    <!-- optional fields -->
    <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="priority" type="xs:unsignedInt" minOccurs="0"/>
    <xs:element name="lang" type="xs:language" minOccurs="0"/>
    <xs:element name="mobility" type="mobilityType" minOccurs="0"/>
    <xs:element name="presentation" type="presentationType" minOccurs="0"/>
    <xs:element name="view" type="viewType" minOccurs="0"/>
    <xs:element name="participantIDs" type="participantIDsType" minOccurs="0"/>
    <xs:element name="maxCaptureEncodings" type="xs:unsignedInt"
    minOccurs="0"/>
    <xs:element name="relatedTo" type="xs:IDREF" minOccurs="0"/>
    <xs:any namespace="##other" processContents="lax" minOccurs="0"
    maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attribute name="captureID" type="xs:ID" use="required"/>
  <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

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10.1.  <capturedMedia>

   <capturedMedia> is a mandatory field specifying the media type of the
   capture ("audio", "video", "text",...).

10.2.  <captureSceneIDREF>

   <captureSceneIDREF> is a mandatory field containing the identifier of
   the capture scene the media capture belongs to.  Indeed, each media
   capture must be associated with one and only one capture scene.  When
   a media capture is spatially definable, some spatial information is
   provided along with it in the form of point coordinates (see
   Section 10.4).  Such coordinates refer to the space of coordinates
   defined for the capture scene containing the capture.

10.3.  <encGroupIDREF>

   <encGroupIDREF> is a mandatory field containing the identifier of the
   encoding group the media capture is associated with.

10.4.  <spatialInformation>

   Media captures are divided into two categories: (i) non spatially
   definable captures and (ii) spatially definable captures.

   Captures are spatially definible when it is possible to provide at
   least the coordinates of the device position within the telepresence
   room of origin.  Such coordinates are expressed according to the
   coordinate space of the capture scene the media captures belongs to.

   Non spatially definable captures cannot be characterized within the
   physical space of the telepresence room of origin.  Captures of this
   kind are for example those related to recordings, text captures,
   DVDs, recorded presentations, or external streams, that are played in
   the telepresence room and transmitted to remote sites.  Another
   example is represented by switched captures: their content, in fact,
   comes from different devices over time.

   Spatially definable captures represent a part of the telepresence
   room.  The captured part of the telepresence room is described by
   means of the <spatialInformation> element.  Non spatially definable
   captures do not show in their XML description such element: they are
   instead characterized by having the <nonSpatiallyDefinable> tag set
   to "true" (see Section 10.5).

   The definition of the spatial information type is the following:

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   <!-- SPATIAL INFORMATION TYPE -->
   <xs:complexType name="spatialInformationType">
    <xs:sequence>
     <xs:element name="capturePoint" type="capturePointType"/>
     <xs:element name="captureArea" type="captureAreaType"
     minOccurs="0"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
     maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:complexType>

   The <capturePoint> contains the coordinates of the capture device
   that is taking the capture, as well as, optionally, the pointing
   direction (see Section 10.4.1).  It is a mandatory field when the
   media capture is spatially definable, independently from the media
   type.

   The <captureArea> is an optional field containing four points
   defining the captured area covered by the capture (see
   Section 10.4.2).

10.4.1.  <capturePoint>

   The <capturePoint> element is used to represent the position and the
   line of capture of a capture device.  The XML Schema definition of
   the <capturePoint> element type is the following:

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   <!-- POINT TYPE -->
   <xs:complexType name="pointType">
    <xs:sequence>
     <xs:element name="x" type="xs:decimal"/>
     <xs:element name="y" type="xs:decimal"/>
     <xs:element name="z" type="xs:decimal"/>
    </xs:sequence>
   </xs:complexType>

   <!-- CAPTURE POINT TYPE -->
   <xs:complexType name="capturePointType">
    <xs:complexContent>
     <xs:extension base="pointType">
      <xs:sequence>
       <xs:element name="lineOfCapturePoint" type="tns:pointType"
       minOccurs="0"/>
      </xs:sequence>
      <xs:attribute name="pointID" type="xs:ID"/>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

   The point type contains three spatial coordinates (x,y,z)
   representing a point in the space associated with a certain capture
   scene.

   The capture point type extends the point type, i.e., it is
   represented by three coordinates identifying the position of the
   capture device, but can carry further information.  Such further
   information is conveyed by the <lineOfCapturePoint>, which is one
   more point-type element representing the "point on line of capture",
   that gives the pointing direction of the capture device.

   The coordinates of the point on line of capture MUST NOT be identical
   to the capture point coordinates.  If the point on line of capture is
   not specified, no assumptions are made about the pointing direction
   of the capturing device.

10.4.2.  <captureArea>

   <captureArea> is an optional element that can be contained within the
   spatial information associated with a media capture.  It represents
   the spatial area captured by the media capture.

   The XML representation of that area is provided through a set of four
   point-type elements, <bottomLeft>, <bottomRight>, <topLeft>, and
   <topRight>, as it can be seen from the following definition:

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   <!-- CAPTURE AREA TYPE -->
   <xs:complexType name="captureAreaType">
    <xs:sequence>
     <xs:element name="bottomLeft" type="pointType"/>
     <xs:element name="bottomRight" type="pointType"/>
     <xs:element name="topLeft" type="pointType"/>
     <xs:element name="topRight" type="pointType"/>
    </xs:sequence>
   </xs:complexType>

   <bottomLeft>, <bottomRight>, <topLeft>, and <topRight> should be co-
   planar.

   By comparing the capture area of different media captures within the
   same capture scene, a consumer can better determine the spatial
   relationships among them and render them correctly.

10.5.  <nonSpatiallyDefinable>

   When media captures are non spatially definable, they are marked with
   the boolean <nonSpatiallyDefinable> element set to "true" and no
   <spatialInformation> is provided.  Indeed, <nonSpatiallyDefinable>
   and <spatialInformation> are mutually exclusive tags, according to
   the <choice> section within the XML Schema definition of the media
   capture type.

10.6.  <content>

   A media capture can be (i) an individual media capture or (ii) a
   multiple content capture (MCC).  A multiple content capture is made
   of different captures that can be arranged spatially (by a
   composition operation), or temporally (by a switching operation), or
   that can result from the proper orchestration of both techniques.  If
   a media capture is a MCC, then it MUST show in its XML data model
   representation the <content> element.  It is a mandatory element
   composed of a list of media capture identifiers ("captureIDREF") and
   capture scene entry identifiers ("sceneEntryIDREF"), where the last
   ones are used as shortcuts to refer to multiple capture identifiers.

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   <!-- CONTENT TYPE -->
   <xs:complexType name="contentType">
    <xs:sequence>
      <xs:element name="captureIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="sceneEntryIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:complexType>

10.7.  <synchronizationID>

   <synchronizationID> is an optional element for multiple content
   captures that contains a numeric identifier.  Multiple content
   captures marked with the same identifier in the <synchronizationID>
   contain, at each point in time, captures coming from the same room
   endpoint.

10.8.  <composed>

   <composed> is an optional boolean element that can be used only for
   multiple content captures.  It indicates whether or not a multiple
   content capture is a mix (audio) or a composition (video) of streams.
   If set to "true", it means that the capture can result at a certain
   point in time from more than one capture.  This attribute is useful
   for a media consumer for example to avoid nesting a composed video
   capture into a different composed capture.

10.9.  <switched>

   <switched> is an optional boolean element that can be used only for
   multiple content captures.  It indicates whether or not a multiple
   content capture switches over time.  If set to "true", it means that
   the content of the MCC (in terms of the actual composing captures)
   can change over time.

10.10.  <policy>

   <policy> is an optional element that can be used only for multiple
   content captures.  It indicates the criteria applied to build the
   multiple content capture using the media captures referenced in
   <contentCaptureIDs>.  Such element can be set to a list of pre-
   defined values ([todo]).

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10.11.  <maxCaptures>

   <maxCaptures> is an optional element that can be used only for
   multiple content captures.  It indicates the maximum number of media
   captures that can be represented in the multiple content capture at a
   time.

10.12.  <individual>

   <individual> is a boolean element that MUST be used for single-
   content captures.  Its value is fixed and set to "true".  Such
   element indicates that the capture being described is not a multiple
   content capture.  Indeed, <individual> and the aforementioned tags
   related to MCC attributes (from Section 10.6 to Section 10.11) are
   mutually exclusive, according to the <choice> section within the XML
   Schema definition of the media capture type.

10.13.  <description>

   <description> is used to optionally provide human-readable textual
   information about a media capture.  The same element is used to
   describe, besides media captures, capture scenes and capture scene
   entries, as it is included in their XML representation.  A media
   capture can be described by using multiple <description> elements,
   each providing information in a different language.  The
   <description> element definition is the following:

   <!-- DESCRIPTION element -->
   <xs:element name="description">
    <xs:complexType>
     <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="lang" type="xs:language"/>
      </xs:extension>
     </xs:simpleContent>
    </xs:complexType>
   </xs:element>

   As it can be seen from the above snippet, <description> is a string
   element with an attribute ("lang") indicating the language used in
   the textual description.

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10.14.  <priority>

   <priority> is an optional unsigned integer field indicating the
   importance of a media capture according to the media provider's
   perspective.  It can be used on the receiver's side to automatically
   identify the most relevant contribution from the media provider.  The
   higher the importance, the lower the contained value.  When media
   captures are marked with a "0" priority value, it means that they are
   "not subject to priority".

10.15.  <lang>

   <lang> is an optional element containing the language used in the
   capture, if any.

10.16.  <mobility>

   <mobility> is an optional element indicating whether or not the
   capture device originating the capture may move during the
   telepresence session.  Such an optional element can assume one of the
   three following values: (i) static, (ii) dynamic or (iii) highly
   dynamic, defined as in [I-D.ietf-clue-framework].

10.17.  <maxCaptureEncodings>

   The optional <maxCaptureEncodings> contains an unsigned integer
   indicating the maximum number of capture encodings that can be
   simultaneously active for the media capture.  If absent, this
   parameter defaults to 1.  The minimum value for this attribute is 1.
   The number of simultaneous capture encodings is also limited by the
   restrictions of the encoding group the media capture refers to by
   means of the <encGroupIDREF> element.

10.18.  <relatedTo>

   The optional <relatedTo> element contains the value of the ID
   attribute of the media capture it refers to.  The media capture
   marked with a <relatedTo> element can be for example the translation
   of a main media capture in a different language.

10.19.  <view>

   The <view> element is an optional tag describing what is represented
   in the spatial area covered by a media capture.  The current possible
   values are: "table", "lectern", "individual", and "audience", as
   listed in the enumerative view type in the following.

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10.20.  <presentation>

   The <presentation> element is an optional tag used for media captures
   conveying information about presentations within the telepresence
   session.  The current possible values are "slides" and "images", as
   listed in the enumerative presentation type in the following.

10.21.  <capturedPeople>

   This optional element is used to indicate which telepresence session
   participants are represented within the media captures.  For each
   participant, a <personIDREF> element is provided.

   [to be discussed]

10.21.1.  <personIDREF>

   <personIDREF> contains the identifier of the represented person.
   Metadata about the represented participant can be retrieved by
   accessing the <people> list (Section 19).

10.22.  captureID attribute

   The "captureID" attribute is a mandatory field containing the
   identifier of the media capture.

11.  Audio captures

   Audio captures inherit all the features of a generic media capture
   and present further audio-specific characteristics.  The XML Schema
   definition of the audio capture type is reported below:

 <!-- AUDIO CAPTURE TYPE -->
 <xs:complexType name="audioCaptureType">
  <xs:complexContent>
   <xs:extension base="tns:mediaCaptureType">
    <xs:sequence>
     <xs:element name="audioChannelFormat" type="audioChannelFormatType"
     minOccurs="0"/>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

   Audio-specific information about the audio capture is contained in

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   <audioChannelFormat> (Section 11.1).

11.1.  <audioChannelFormat>

   The optional <audioChannelFormat> element is a field with enumerated
   values ("mono" and "stereo") which describes the method of encoding
   used for audio.  A value of "mono" means the audio capture has one
   channel.  A value of "stereo" means the audio capture has two audio
   channels, left and right.  A single stereo capture is different from
   two mono captures that have a left-right spatial relationship.  A
   stereo capture maps to a single RTP stream, while each mono audio
   capture maps to a separate RTP stream.

   The XML Schema definition of the <audioChannelFormat> element type is
   provided below:

   <!-- AUDIO CHANNEL FORMAT TYPE -->
   <xs:simpleType name="audioChannelFormatType">
    <xs:restriction base="xs:string">
     <xs:enumeration value="mono"/>
     <xs:enumeration value="stereo"/>
    </xs:restriction>
   </xs:simpleType>

12.  Video captures

   Video captures, similarly to audio captures, extend the information
   of a generic media capture with video-specific features, such as
   <embeddedText> (Section 12.1).

   The XML Schema representation of the video capture type is provided
   in the following:

   <!-- VIDEO CAPTURE TYPE -->
   <xs:complexType name="videoCaptureType">
    <xs:complexContent>
     <xs:extension base="tns:mediaCaptureType">
      <xs:sequence>
       <xs:element ref="embeddedText" minOccurs="0"/>
      </xs:sequence>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

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12.1.  <embeddedText>

   The <embeddedText> element is a boolean element indicating that there
   is text embedded in the video capture.  The language used in such
   embedded textual description is reported in the "lang" attribute.

   The XML Schema definition of the <embeddedText> element is:

   <!-- EMBEDDED TEXT ELEMENT -->
   <xs:element name="embeddedText">
    <xs:complexType>
     <xs:simpleContent>
      <xs:extension base="xs:boolean">
       <xs:attribute name="lang" type="xs:language"/>
      </xs:extension>
     </xs:simpleContent>
    </xs:complexType>

   </xs:element>

13.  Text captures

   Also text captures can be described by extending the generic media
   capture information, similarly to audio captures and video captures.

   The XML Schema representation of the text capture type is currently
   lacking text-specific information, as it can be seen by looking at
   the definition below:

   <!-- TEXT CAPTURE TYPE -->
   <xs:complexType name="textCaptureType">
    <xs:complexContent>
     <xs:extension base="tns:mediaCaptureType">
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

14.  <captureScene>

   A media provider organizes the available captures in capture scenes
   in order to help the receiver both in the rendering and in the
   selection of the group of captures.  Capture scenes are made of

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   capture scene entries, that are a set of media captures of the same
   media type.  Each capture scene entry represents an alternative to
   thoroughly represent a capture scene for a fixed media type.

   The XML Schema representation of a <captureScene> element is the
   following:

<!-- CAPTURE SCENE TYPE -->
<xs:complexType name="captureSceneType">
 <xs:sequence>
  <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
  <xs:element name="sceneInformation" type="xcard:vcardType" minOccurs="0"/>
  <xs:element name="sceneEntries" type="sceneEntriesType"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
  maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="sceneID" type="xs:ID" use="required"/>
 <xs:attribute name="scale" type="scaleType" use="required"/>
 <xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>

   The <captureScene> element can contain zero or more textual
   <description> elements, defined as in Section 10.13.  Besides
   <description>, there is the <sceneInformation> element
   (Section 14.1), which contains structured information about the scene
   in the vcard format, as well as the <sceneEntries> element
   (Section 14.2), which is the list of available capture scene entries.

14.1.  <sceneInformation>

   The <sceneInformation> element contains optional information about
   the capture scene according to the vcard format.

14.2.  <sceneEntries>

   The <sceneEntries> element is a mandatory field of a capture scene
   containing the list of scene entries.  Each scene entry is
   represented by a <sceneEntry> element (Section 15).

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   <!-- SCENE ENTRIES TYPE -->
   <!-- envelope of scene entries of a capture scene -->
   <xs:complexType name="sceneEntriesType">
    <xs:sequence>
     <xs:element name="sceneEntry" type="sceneEntryType"
     maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

14.3.  sceneID attribute

   The sceneID attribute is a mandatory attribute containing the
   identifier of the capture scene.

14.4.  scale attribute

   The scale attribute is a mandatory attribute that specifies the scale
   of the coordinates provided in the spatial information of the media
   capture belonging to the considered capture scene.  The scale
   attribute can assume three different values:

      "millimeters" - the scale is in millimeters.  Systems which know
      their physical dimensions (for example professionally installed
      telepresence room systems) should always provide those real-world
      measurements.

      "unknown" - the scale is not necessarily millimeters, though it is
      the same for every media capture in the capture scene.  Systems
      which don't know specific physical dimensions but still know
      relative distances should select "unknown" in the scale attribute
      of the capture scene to be described.

      "noscale" - there is no common physical scale among the media
      captures of the capture scene.  That means the scale might be
      different for each media capture.

   <!-- SCALE TYPE -->
   <xs:simpleType name="scaleType">
    <xs:restriction base="xs:string">
     <xs:enumeration value="millimeters"/>
     <xs:enumeration value="unknown"/>
     <xs:enumeration value="noscale"/>
    </xs:restriction>
   </xs:simpleType>

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15.  <sceneEntry>

   A <sceneEntry> element represents a capture scene entry, which
   contains a set of media captures of the same media type describing a
   capture scene.

   A <sceneEntry> element is characterized as follows.

   <!-- SCENE ENTRY TYPE -->
   <xs:complexType name="sceneEntryType">
    <xs:sequence>
     <xs:element ref="description" minOccurs="0" maxOccurs="unbounded"/>
     <xs:element name="mediaCaptureIDs" type="captureIDListType"/>
    </xs:sequence>
    <xs:attribute name="sceneEntryID" type="xs:ID" use="required"/>
    <xs:attribute name="mediaType" type="xs:string" use="required"/>
   </xs:complexType>

   One or more optional <description> elements provide human-readable
   information about the contents of a scene entry. <description> is
   defined as already seen in Section 10.13.

   The remaining child elements are described in the following
   subsections.

15.1.  <mediaCaptureIDs>

   The <mediaCaptureIDs> is the list of the identifiers of the media
   captures included in the scene entry.  It is an element of the
   captureIDListType type, which is defined as a sequence of
   <captureIDREF> elements, each containing the identifier of a media
   capture listed within the <mediaCaptures> element:

   <!-- CAPTURE ID LIST TYPE -->
   <xs:complexType name="captureIDListType">
    <xs:sequence>
     <xs:element name="captureIDREF" type="xs:IDREF"
     maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

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15.2.  sceneEntryID attribute

   The sceneEntryID attribute is a mandatory attribute containing the
   identifier of the capture scene entry represented by the <sceneEntry>
   element.

15.3.  mediaType attribute

   The mediaType attribute contains the media type of the media captures
   included in the scene entry.

16.  <encodingGroup>

   The <encodingGroup> element represents an encoding group, which is
   made of a set of one or more individual encodings and some parameters
   that apply to the group as a whole.  Encoding groups contain
   references to individual encodings that can be applied to captures of
   the same media type.  In other words, they can group audio encodings
   or, alternatively, video encodings.  The definition of the
   <encodingGroup> element is the following:

   <!-- ENCODING GROUP TYPE -->
   <xs:complexType name="encodingGroupType">
    <xs:sequence>
     <xs:element name="maxGroupBandwidth" type="xs:integer"/>
     <xs:element name="encodingIDList" type="encodingIDListType"/>
     <xs:any namespace="##other" processContents="lax" minOccurs="0"
     maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="encodingGroupID" type="xs:ID" use="required"/>
    <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   In the following, the inner elements are further described.

16.1.  <maxGroupBandwidth>

   <maxGroupBandwidth> is an optional field containing the maximum
   bitrate that can be shared by the individual encodings included in
   the encoding group.

16.2.  <encodingIDList>

   <encodingIDList> is the list of the individual encodings grouped
   together in the encoding group.  Each individual encoding is

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   represented through its identifier contained within an <encID>
   element.

   <!-- ENCODING ID LIST TYPE -->
   <xs:complexType name="encodingIDListType">
    <xs:sequence>
     <xs:element name="encID" type="xs:IDREF" maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

16.3.  encodingGroupID attribute

   The encodingGroupID attribute contains the identifier of the encoding
   group.

17.  <simultaneousSet>

   <simultaneousSet> represents a simultaneous transmission set, i.e., a
   list of captures of the same media type that can be transmitted at
   the same time by a media provider.  There are different simultaneous
   transmission sets for each media type.

   <!-- SIMULTANEOUS SET TYPE -->
   <xs:complexType name="simultaneousSetType">
    <xs:sequence>
      <xs:element name="captureIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="sceneEntryIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
   </xs:complexType>

   Besides the identifiers of the captures (<captureIDREF> elements),
   also the identifiers of capture scene entries can be exploited, as
   shortcuts (<sceneEntryIDREF> elements).

17.1.  <captureIDREF>

   <captureIDREF> contains the identifier of the media capture that
   belongs to the simultaneous set.

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17.2.  <sceneEntryIDREF>

   <captureIDREF> contains the identifier of the scene entry containing
   a group of captures that can be sent simultaneously with the
   companion captures in the simultaneous set.

18.  <globalSceneEntry>

   <globalSceneEntry> represents a set of captures of the same media
   type representing a summary of the complete Media Provider's offer.
   The media type of a global scene entry is reported in the "mediaType"
   attribute.  The content of a global scene entry is expressed by
   leveraging scene entry identifiers, put within <sceneEntryIDREF>
   elements.  Each global scene entry is identified by a unique
   identifier within the "globalSceneEntryID" attribute.

   <!-- GLOBAL SCENE ENTRY TYPE -->
   <xs:complexType name="globalSceneEntryType">
    <xs:sequence>
      <xs:element name="sceneEntryIDREF" type="xs:IDREF"
      minOccurs="0" maxOccurs="unbounded"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="globalSceneEntryID" type="xs:ID"/>
    <xs:attribute name="mediaType" type="xs:string" use="required"/>
    <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

19.  <people>

   Information about the participants that are represented in the media
   captures is conveyed via the <people> element.  As it can be seen
   from the XML Schema excerpt reported below, for each participant, a
   <person> element is provided.

   [to be discussed]

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 <!-- PEOPLE TYPE -->
 <xs:complexType name="peopleType">
 <xs:sequence>
 <xs:element name="person" type="personType"
                     maxOccurs="unbounded"/>
 </xs:sequence>
 </xs:complexType>

 <!-- PERSON TYPE -->
 <xs:complexType name="personType">
   <xs:sequence>
      <xs:element name="personInfo" type="xcard:vcardType" maxOccurs="1"
                          minOccurs="0"/>
      <xs:element name="personType" type="personTypeType"
                          minOccurs="0"
                  maxOccurs="unbounded"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0"
                  maxOccurs="unbounded"/>
   </xs:sequence>
   <xs:attribute name="personID" type="xs:ID"/>
   <xs:anyAttribute namespace="##other" processContents="lax"/>
 </xs:complexType>

 <!-- PERSON TYPE TYPE -->
 <xs:simpleType name="personTypeType">
         <xs:restriction base="xs:string">
         <xs:enumeration value="chairman"/>
         <xs:enumeration value="vice-chairman"/>
         <xs:enumeration value="minute taker"/>
         <xs:enumeration value="presenter"/>
         <xs:enumeration value="translator"/>
         <xs:enumeration value="timekeeper"/>
         <xs:enumeration value="attendee"/>
         </xs:restriction>
 </xs:simpleType>

19.1.  <person>

   <person> includes all the metadata related to a person represented
   within one or more media captures.  Such an element currently
   provides at least the vcard of the person (via the <personInfo>
   element, see Section 19.1.2) and optionally his conference role(s)
   (via one or more <personType> elements, see Section 19.1.3).
   Furthermore, it has a mandatory "personID" attribute
   (Section 19.1.1).

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19.1.1.  personID attribute

   The "personID" attribute carries the identifier of a represented
   person.  Such identifier can be used to refer to the participant, as
   in the <capturedPeople> element inside the media captures
   representation (Section 10.21).

19.1.2.  <personInfo>

   The <personInfo> element is the XML representation of all the fields
   composing a vcard as specified in the Xcard RFC [RFC6351].  The
   vcardType is imported by the Xcard XML Schema provided by
   [I-D.ietf-ecrit-additional-data].  As such schema specifies, the <fn>
   element within <vcard> is mandatory.

19.1.3.  <personType>

   The value of the <personType> element determines the role of the
   represented participant within the telepresence session.  It can be
   one of the following terms, that are defined in the framework
   document: "presenter", "timekeeper","attendee", "minute taker",
   "translator", "chairman", "vice-chairman".

   A participant can play more than one conference role.  In that case,
   more than one <personType> element will appear in his description.

20.  <captureEncoding>

   A <captureEncoding> is composed of the association between a media
   capture and an individual encoding, forming a capture stream as
   defined in [I-D.ietf-clue-framework].  A possible solution to model
   such an entity is provided in the following.

<!-- CAPTURE ENCODING TYPE -->
<xs:complexType name="captureEncodingType">
 <xs:sequence>
  <xs:element name="captureID" type="xs:string"/>
  <xs:element name="encodingID" type="xs:string"/>
  <xs:element name="configuredContent" type="contentType" minOccurs="0"/>
  <xs:any namespace="##other" processContents="lax" minOccurs="0"
   maxOccurs="unbounded"/>
 </xs:sequence>
 <xs:attribute name="ID" type="xs:ID"/>
 <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>

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20.1.  <captureID>

   <captureID> is the mandatory element containing the identifier of the
   media capture that has been encoded to form the capture encoding.

20.2.  <encodingID>

   <encodingID> is the mandatory element containing the identifier of
   the applied individual encoding.

20.3.  <configuredContent>

   <configuredContent> is an optional element to be used in case of
   configuration of MCCs.  It contains the list of capture identifiers
   and capture scene entry identifiers the Media Consumer wants within
   the MCC.  That element is structured as the <content> element used to
   describe the content of a MCC.  The total number of media captures
   listed in the <configuredContent> must be lower than or equal to the
   value carried within the <maxCaptures> attribute of the MCC.

21.  <clueInfo>

   The <clueInfo> element has been left within the XML Schema for
   representing a drafty version of the body of an ADVERTISEMENT message
   (see the example section).

   <!-- CLUE INFO ELEMENT -->
   <!-- the <clueInfo> envelope can be seen
        as the ancestor of an <advertisement> envelope -->
   <xs:element name="clueInfo" type="clueInfoType"/>

   <!-- CLUE INFO TYPE -->
   <xs:complexType name="clueInfoType">
     <xs:sequence>
      <xs:element ref="mediaCaptures"/>
      <xs:element ref="encodingGroups"/>
      <xs:element ref="captureScenes"/>
      <xs:element ref="simultaneousSets" minOccurs="0"/>
      <xs:element ref="globalSceneEntries" minOccurs="0"/>
      <xs:element ref="people" minOccurs="0"/>
      <xs:any namespace="##other" processContents="lax" minOccurs="0"
      maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attribute name="clueInfoID" type="xs:ID" use="required"/>
     <xs:anyAttribute namespace="##other" processContents="lax"/>
   </xs:complexType>

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22.  Sample XML file

   The following XML document represents a schema compliant example of a
   CLUE telepresence scenario.  Taking inspiration from the examples
   described in the framework draft ([I-D.ietf-clue-framework]), the XML
   representation of an endpoint-style Media Provider's offer is herein
   provided.

   There are three cameras, where the central one is also able to
   capture a zoomed-out view of the overall telepresence room.  Besides
   the three video captures coming from such cameras, the MP makes
   available a further multi-content capture about the loudest segment
   of the room, obtained by switching the video source across the three
   cameras.  For the sake of simplicity, only one audio capture is
   advertised for the audio of the whole room.

   The three cameras are placed in front of three participants (Alice,
   Bob and Ciccio), whose vcard and conference role details are also
   provided.

   Media captures are arranged into four capture scene entries:

   1.  (VC0, VC1, VC2) - left, center and right camera video captures

   2.  (VC3) - video capture associated with loudest room segment

   3.  (VC4) - video capture zoomed out view of all people in the room

   4.  (AC0) - main audio

   There are two encoding groups: (i) EG0, for video encodings, and (ii)
   EG1, for audio encodings.

   As to the simultaneous sets, only VC1 and VC4 cannot be transmitted
   simultaneously since they are captured by the same device, i.e., the
   central camera (VC4 is a zoomed-out view while VC1 is a focused view
   of the front participant).  The simultaneous sets would then be the
   following:

   SS1  composed of VC3 and all the captures in the first capture scene
      entry (VC0,VC1,VC2);

   SS2  composed of VC3, VC0, VC2, VC4

Fri_Jun_13_16_16_16_CEST_2014_mccExample

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<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<clueInfo xmlns="urn:ietf:params:xml:ns:clue-info"
xmlns:ns2="urn:ietf:params:xml:ns:vcard-4.0" clueInfoID="NapoliRoom">
    <mediaCaptures>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="AC0">
            <capturedMedia>audio</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG1</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">main audio from the room</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>room</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
                <personIDREF>bob</personIDREF>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC0">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>

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                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">left camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <capturedPeople>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC1">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">central camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC2">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>

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                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">right camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <capturedPeople>
                <personIDREF>bob</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC3">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
            <composed>false</composed>
            <switched>true</switched>
            <policy>Soundlevel:0</policy>
            <maxCaptures>1</maxCaptures>
            <description lang="en">loudest room segment</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC4">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>

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                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">zoomed out view of all people in the room
            </description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>room</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
                <personIDREF>bob</personIDREF>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
    </mediaCaptures>
    <encodingGroups>
        <encodingGroup encodingGroupID="EG0">
            <maxGroupBandwidth>600000</maxGroupBandwidth>
            <encodingIDList>
                <encID>ENC1</encID>
                <encID>ENC2</encID>
                <encID>ENC3</encID>
            </encodingIDList>
        </encodingGroup>
        <encodingGroup encodingGroupID="EG1">
            <maxGroupBandwidth>300000</maxGroupBandwidth>
            <encodingIDList>
                <encID>ENC4</encID>
                <encID>ENC5</encID>
            </encodingIDList>
        </encodingGroup>
    </encodingGroups>
    <captureScenes>
        <captureScene scale="unknown" sceneID="CS1">
            <sceneEntries>
                <sceneEntry mediaType="video" sceneEntryID="SE1">
                    <mediaCaptureIDs>
                        <captureIDREF>VC0</captureIDREF>
                        <captureIDREF>VC1</captureIDREF>
                        <captureIDREF>VC2</captureIDREF>

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                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="video" sceneEntryID="SE2">
                    <mediaCaptureIDs>
                        <captureIDREF>VC3</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="video" sceneEntryID="SE3">
                    <mediaCaptureIDs>
                        <captureIDREF>VC4</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="audio" sceneEntryID="SE4">
                    <mediaCaptureIDs>
                        <captureIDREF>AC0</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
            </sceneEntries>
        </captureScene>
    </captureScenes>
    <simultaneousSets>
        <simultaneousSet setID="SS1">
            <captureIDREF>VC3</captureIDREF>
            <sceneEntryIDREF>SE1</sceneEntryIDREF>
        </simultaneousSet>
        <simultaneousSet setID="SS2">
            <captureIDREF>VC0</captureIDREF>
            <captureIDREF>VC2</captureIDREF>
            <captureIDREF>VC4</captureIDREF>
            <captureIDREF>VC3</captureIDREF>
        </simultaneousSet>
    </simultaneousSets>
    <people>
        <person personID="bob">
            <personInfo>
                <ns2:fn>
                    <ns2:text>Bob</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>minute taker</personType>
        </person>
        <person personID="alice">
            <personInfo>
                <ns2:fn>
                    <ns2:text>Alice</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>presenter</personType>

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        </person>
        <person personID="ciccio">
            <personInfo>
                <ns2:fn>
                    <ns2:text>Ciccio</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>chairman</personType>
            <personType>timekeeper</personType>
        </person>
    </people>
</clueInfo>

23.  MCC example

   Enhancing the scenario presented in the previous example, the media
   provider is able to advertise a composed capture VC7 composed of a
   big picture representing the current speaker (VC3) and two picture-
   in-picture boxes representing the previous speakers (the previous one
   -VC5- and the oldest one -VC6).  The provider does not want to
   instantiate and send VC5 and VC6, so it does not associate any
   encoding group with them.  Their XML representations are provided for
   enabling the description of VC7.

   A possible description for that scenario could be the following:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<clueInfo xmlns="urn:ietf:params:xml:ns:clue-info"
xmlns:ns2="urn:ietf:params:xml:ns:vcard-4.0"
clueInfoID="NapoliRoom">
    <mediaCaptures>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="AC0">
            <capturedMedia>audio</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG1</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>

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                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">main audio from the room</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>room</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
                <personIDREF>bob</personIDREF>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC0">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">left camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <capturedPeople>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC1">
            <capturedMedia>video</capturedMedia>

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            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">central camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC2">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">right camera video capture</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>

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            <capturedPeople>
                <personIDREF>bob</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>2</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC3">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
            <content>
                <sceneEntryIDREF>SE1</sceneEntryIDREF>
            </content>
            <composed>false</composed>
            <switched>true</switched>
            <policy>Soundlevel:0</policy>
            <maxCaptures>1</maxCaptures>
            <description lang="en">loudest room segment</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC4">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <encGroupIDREF>EG0</encGroupIDREF>
            <spatialInformation>
                <capturePoint>
                    <x>0.5</x>
                    <y>1.0</y>
                    <z>0.5</z>
                    <lineOfCapturePoint>
                        <x>0.5</x>
                        <y>0.0</y>
                        <z>0.5</z>
                    </lineOfCapturePoint>
                </capturePoint>
            </spatialInformation>
            <individual>true</individual>
            <description lang="en">zoomed out view of all people in the room
            </description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>

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            <view>room</view>
            <capturedPeople>
                <personIDREF>alice</personIDREF>
                <personIDREF>bob</personIDREF>
                <personIDREF>ciccio</personIDREF>
            </capturedPeople>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC5">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
            <content>
                <sceneEntryIDREF>SE1</sceneEntryIDREF>
            </content>
            <composed>false</composed>
            <switched>true</switched>
            <policy>Soundlevel:1</policy>
            <maxCaptures>1</maxCaptures>
            <description lang="en">penultimate loudest room segment
            </description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC6">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
            <content>
                <sceneEntryIDREF>SE1</sceneEntryIDREF>
            </content>
            <composed>false</composed>
            <switched>true</switched>
            <policy>Soundlevel:2</policy>
            <maxCaptures>1</maxCaptures>
            <description lang="en">last but two loudest room segment
            </description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>

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        <mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:type="videoCaptureType" captureID="VC7">
            <capturedMedia>video</capturedMedia>
            <captureSceneIDREF>CS1</captureSceneIDREF>
            <nonSpatiallyDefinable>true</nonSpatiallyDefinable>
            <content>
                <captureIDREF>VC3</captureIDREF>
                <captureIDREF>VC5</captureIDREF>
                <captureIDREF>VC6</captureIDREF>
            </content>
            <composed>true</composed>
            <switched>true</switched>
            <maxCaptures>1</maxCaptures>
            <description lang="en">big picture of the current speaker + pips
            about previous speakers</description>
            <priority>1</priority>
            <lang>it</lang>
            <mobility>static</mobility>
            <view>individual</view>
            <maxCaptureEncodings>1</maxCaptureEncodings>
        </mediaCapture>
    </mediaCaptures>
    <encodingGroups>
        <encodingGroup encodingGroupID="EG0">
            <maxGroupBandwidth>600000</maxGroupBandwidth>
            <encodingIDList>
                <encID>ENC1</encID>
                <encID>ENC2</encID>
                <encID>ENC3</encID>
            </encodingIDList>
        </encodingGroup>
        <encodingGroup encodingGroupID="EG1">
            <maxGroupBandwidth>300000</maxGroupBandwidth>
            <encodingIDList>
                <encID>ENC4</encID>
                <encID>ENC5</encID>
            </encodingIDList>
        </encodingGroup>
    </encodingGroups>
    <captureScenes>
        <captureScene scale="unknown" sceneID="CS1">
            <sceneEntries>
                <sceneEntry mediaType="video" sceneEntryID="SE1">
                    <description lang="en">participants' individual videos
                    </description>
                    <mediaCaptureIDs>
                        <captureIDREF>VC0</captureIDREF>
                        <captureIDREF>VC1</captureIDREF>

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                        <captureIDREF>VC2</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="video" sceneEntryID="SE2">
                    <description lang="en">loudest segment of the room
                    </description>
                    <mediaCaptureIDs>
                        <captureIDREF>VC3</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="video" sceneEntryID="SE5">
                    <description lang="en">loudest segment of the room + pips
                    </description>
                    <mediaCaptureIDs>
                        <captureIDREF>VC7</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="audio" sceneEntryID="SE4">
                    <description lang="en">room audio</description>
                    <mediaCaptureIDs>
                        <captureIDREF>AC0</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
                <sceneEntry mediaType="video" sceneEntryID="SE3">
                    <description lang="en">room video</description>
                    <mediaCaptureIDs>
                        <captureIDREF>VC4</captureIDREF>
                    </mediaCaptureIDs>
                </sceneEntry>
            </sceneEntries>
        </captureScene>
    </captureScenes>
    <simultaneousSets>
        <simultaneousSet setID="SS1">
            <captureIDREF>VC7</captureIDREF>
            <sceneEntryIDREF>SE1</sceneEntryIDREF>
        </simultaneousSet>
        <simultaneousSet setID="SS2">
            <captureIDREF>VC0</captureIDREF>
            <captureIDREF>VC2</captureIDREF>
            <captureIDREF>VC4</captureIDREF>
            <captureIDREF>VC7</captureIDREF>
        </simultaneousSet>
    </simultaneousSets>
    <people>
        <person personID="bob">
            <personInfo>
                <ns2:fn>

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                    <ns2:text>Bob</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>minute taker</personType>
        </person>
        <person personID="alice">
            <personInfo>
                <ns2:fn>
                    <ns2:text>Alice</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>presenter</personType>
        </person>
        <person personID="ciccio">
            <personInfo>
                <ns2:fn>
                    <ns2:text>Ciccio</ns2:text>
                </ns2:fn>
            </personInfo>
            <personType>chairman</personType>
            <personType>timekeeper</personType>
        </person>
    </people>
</clueInfo>

24.  Diff with  draft-ietf-clue-data-model-schema-02 version

      captureParameters and encodingParameters have been removed from
      the captureEncodingType

      data model example has been updated and validated according to the
      new schema.  Further description of the represented scenario has
      been provided.

      A multiple content capture example has been added.

      Obsolete comments and references have been removed.

25.  Diff with draft-ietf-clue-data-model-schema-03 version

      encodings section has been removed

      global capture entries have been introduced

      capture scene entry identifiers are used as shortcuts in listing
      the content of MCC (similarly to simultaneous set and global
      capture entries)

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      Examples have been updated.  A new example with global capture
      entries has been added.

      <encGroupIDREF> has been made optional.

      <single> has been renamed into <individual>

      Obsolete comments have been removed.

      participants information has been added.

26.  Diff with draft-ietf-clue-data-model-schema-04 version

      globalCaptureEntries/Entry renamed as globalSceneEntries/Entry;

      sceneInformation added;

      Only capture scene entry identifiers listed within global scene
      entries (media capture identifiers removed);

      <participants> renamed as <people> in the >clueInfo< template

      <vcard> renamed as <personInfo> to synch with the framework
      terminology

      <participantType> renamed as <personType> to synch with the
      framework terminology

      <participantIDs> renamed as <capturedPeople> in the media capture
      type definition to remove ambiguity

      Examples have been updated with the new definitions of
      <globalSceneEntries> and of <people>.

27.  Informative References

   [I-D.ietf-clue-framework]         Duckworth, M., Pepperell, A., and
                                     S. Wenger, "Framework for
                                     Telepresence Multi-Streams",
                                     draft-ietf-clue-framework-15 (work
                                     in progress), May 2014.

   [I-D.ietf-ecrit-additional-data]  Rosen, B., Tschofenig, H.,
                                     Marshall, R., Randy, R., and J.
                                     Winterbottom, "Additional Data
                                     related to an Emergency Call",
                                     draft-ietf-ecrit-additional-data-22
                                     (work in progress), April 2014.

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   [RFC4796]                         Hautakorpi, J. and G. Camarillo,
                                     "The Session Description Protocol
                                     (SDP) Content Attribute", RFC 4796,
                                     February 2007.

   [RFC6351]                         Perreault, S., "xCard: vCard XML
                                     Representation", RFC 6351,
                                     August 2011.

Authors' Addresses

   Roberta Presta
   University of Napoli
   Via Claudio 21
   Napoli  80125
   Italy

   EMail: roberta.presta@unina.it

   Simon Pietro Romano
   University of Napoli
   Via Claudio 21
   Napoli  80125
   Italy

   EMail: spromano@unina.it

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