RTP Payload Format for the Enhanced Variable Rate Wideband Codec (EVRC-WB) and the Media Subtype Updates for EVRC-B Codec
RFC 5188
Document | Type |
RFC - Proposed Standard
(February 2008; No errata)
Updates RFC 4788
|
|
---|---|---|---|
Authors | Qiaobing Xie , HariKishan Desineni , Qiaobing Xie | ||
Last updated | 2015-10-14 | ||
Replaces | draft-hdesinen-avt-rtp-evrc-wb | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5188 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Cullen Jennings | ||
Send notices to | (None) |
Network Working Group H. Desineni Request for Comments: 5188 Qualcomm Updates: 4788 Q. Xie Category: Standards Track Motorola February 2008 RTP Payload Format for the Enhanced Variable Rate Wideband Codec (EVRC-WB) and the Media Subtype Updates for EVRC-B Codec Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document specifies Real-time Transport Protocol (RTP) payload formats to be used for the Enhanced Variable Rate Wideband Codec (EVRC-WB) and updates the media type registrations for EVRC-B codec. Several media type registrations are included for EVRC-WB RTP payload formats. In addition, a file format is specified for transport of EVRC-WB speech data in storage mode applications such as email. Desineni & Xie Standards Track [Page 1] RFC 5188 EVRC-WB RTP Payload Format February 2008 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. EVRC-WB Codec . . . . . . . . . . . . . . . . . . . . . . . . 3 5. RTP Header Usage . . . . . . . . . . . . . . . . . . . . . . . 4 6. Payload Format . . . . . . . . . . . . . . . . . . . . . . . . 4 7. Congestion Control Considerations . . . . . . . . . . . . . . 5 8. Storage Format for the EVRC-WB Codec . . . . . . . . . . . . . 5 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 9.1. Media Type Registrations . . . . . . . . . . . . . . . . . 5 9.1.1. Registration of Media Type audio/EVRCWB . . . . . . . 6 9.1.2. Registration of Media Type audio/EVRCWB0 . . . . . . . 8 9.1.3. Registration of Media Type audio/EVRCWB1 . . . . . . . 9 9.1.4. Updated Registration of Media Type audio/EVRCB . . . . 11 9.1.5. Updated Registration of Media Type audio/EVRCB0 . . . 13 10. SDP Mode Attributes for EVRC-WB and EVRC-B . . . . . . . . . . 15 11. EVRC-B Interoperability with Legacy Implementations (RFC 4788) 15 12. Mapping EVRC-WB Media Type Parameters into SDP . . . . . . . . 16 13. Mapping EVRC-B Media Type Parameters into SDP . . . . . . . . 16 14. Offer-Answer Model Considerations for EVRC-WB . . . . . . . . 16 15. Offer-Answer Model Considerations for EVRC-B . . . . . . . . . 18 16. Declarative SDP Considerations . . . . . . . . . . . . . . . . 18 17. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 18. Security Considerations . . . . . . . . . . . . . . . . . . . 22 19. Changes to RFC 4788 . . . . . . . . . . . . . . . . . . . . . 22 20. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22 20.1. Normative References . . . . . . . . . . . . . . . . . . . 22 20.2. Informative References . . . . . . . . . . . . . . . . . . 23 Desineni & Xie Standards Track [Page 2] RFC 5188 EVRC-WB RTP Payload Format February 2008 1. Introduction This document specifies the payload formats for packetization of EVRC-WB encoded speech signals into the Real-time Transport Protocol (RTP). It defines support for the header-free, interleaved/bundled, and compact bundle packet formats for the EVRC-WB codec as well as discontinuous transmission (DTX) support for EVRC-WB encoded speech transported via RTP. The EVRC-WB codec offers better speech quality than the EVRC and EVRC-B codecs. EVRC-WB belongs to the EVRC family of codecs. This document also updates the media type registrations for the EVRC-B codec. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1]. 3. Background EVRC-WB is a wideband extension of the EVRC-B [4] speech codec developed in the Third Generation Partnership Project 2 (3GPP2) with support for discontinuous transmission (DTX). It provides enhanced (wideband) voice quality. The EVRC-WB codec operates on 20-ms frames, and the default sampling rate is 16 kHz. Input and output at an 8-kHz sampling rate are also supported. The EVRC-WB codec can operate in three modes (0, 4, andShow full document text