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RTP Payload Format for Enhanced Variable Rate Codecs (EVRC) and Selectable Mode Vocoders (SMV) (RFC3558)

IP.com Disclosure Number: IPCOM000013146D
Original Publication Date: 2003-Jul-01
Included in the Prior Art Database: 2003-Jul-29
Document File: 24 page(s) / 50K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

A. Li: AUTHOR

Abstract

This document describes the RTP payload format for Enhanced Variable Rate Codec (EVRC) Speech and Selectable Mode Vocoder (SMV) Speech. Two sub-formats are specified for different application scenarios. A bundled/interleaved format is included to reduce the effect of packet loss on speech quality and amortize the overhead of the RTP header over more than one speech frame. A non-bundled format is also supported for conversational applications.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 6% of the total text.

Network Working Group                                              A. Li

Request for Comments: 3558                                          UCLA

Category: Standards Track                                      July 2003

      RTP Payload Format for Enhanced Variable Rate Codecs (EVRC)

                   and Selectable Mode Vocoders (SMV)

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.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes the RTP payload format for Enhanced Variable

   Rate Codec (EVRC) Speech and Selectable Mode Vocoder (SMV) Speech.

   Two sub-formats are specified for different application scenarios.  A

   bundled/interleaved format is included to reduce the effect of packet

   loss on speech quality and amortize the overhead of the RTP header

   over more than one speech frame.  A non-bundled format is also

   supported for conversational applications.

Table of Contents

   1. Introduction ................................................... 2

   2. Background ..................................................... 2

   3. The Codecs Supported ........................................... 3

      3.1. EVRC ...................................................... 3

      3.2. SMV ....................................................... 3

      3.3. Other Frame-Based Vocoders ................................ 4

   4. RTP/Vocoder Packet Format ...................................... 4

      4.1. Interleaved/Bundled Packet Format ......................... 5

      4.2. Header-Free Packet Format ................................. 6

      4.3. Determining the Format of Packets ......................... 7

   5. Packet Table of Contents Entries and Codec Data Frame Format ... 7

      5.1. Packet Table of Contents entries .......................... 7

      5.2. Codec Data Frames ......................................... 8

   6. Interleaving Codec Data Frames ................................. 9

   7. Bundling Codec Data Frames .................................... 12

   8. Handling Missing Codec Data Frames ............................ 12

Li                          Standards Track                     [Page 1]

RFC 3558          RTP Payload Format for EVRC and SMV          July 2003

   9. Implementation Issues ......................................... 12

      9.1. Interleaving Length .............................