RTP Profile for Audio and Video Conferences with Minimal Control
RFC 3551

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Network Working Group                                     H. Schulzrinne
Request for Comments: 3551                           Columbia University
Obsoletes: 1890                                                S. Casner
Category: Standards Track                                  Packet Design
                                                               July 2003

              RTP Profile for Audio and Video Conferences
                          with Minimal Control

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 a profile called "RTP/AVP" for the use of the
   real-time transport protocol (RTP), version 2, and the associated
   control protocol, RTCP, within audio and video multiparticipant
   conferences with minimal control.  It provides interpretations of
   generic fields within the RTP specification suitable for audio and
   video conferences.  In particular, this document defines a set of
   default mappings from payload type numbers to encodings.

   This document also describes how audio and video data may be carried
   within RTP.  It defines a set of standard encodings and their names
   when used within RTP.  The descriptions provide pointers to reference
   implementations and the detailed standards.  This document is meant
   as an aid for implementors of audio, video and other real-time
   multimedia applications.

   This memorandum obsoletes RFC 1890.  It is mostly backwards-
   compatible except for functions removed because two interoperable
   implementations were not found.  The additions to RFC 1890 codify
   existing practice in the use of payload formats under this profile
   and include new payload formats defined since RFC 1890 was published.

Schulzrinne & Casner        Standards Track                     [Page 1]
RFC 3551                    RTP A/V Profile                    July 2003

Table of Contents

   1.  Introduction .................................................  3
       1.1  Terminology .............................................  3
   2.  RTP and RTCP Packet Forms and Protocol Behavior ..............  4
   3.  Registering Additional Encodings .............................  6
   4.  Audio ........................................................  8
       4.1  Encoding-Independent Rules ..............................  8
       4.2  Operating Recommendations ...............................  9
       4.3  Guidelines for Sample-Based Audio Encodings ............. 10
       4.4  Guidelines for Frame-Based Audio Encodings .............. 11
       4.5  Audio Encodings ......................................... 12
            4.5.1   DVI4 ............................................ 13
            4.5.2   G722 ............................................ 14
            4.5.3   G723 ............................................ 14
            4.5.4   G726-40, G726-32, G726-24, and G726-16 .......... 18
            4.5.5   G728 ............................................ 19
            4.5.6   G729 ............................................ 20
            4.5.7   G729D and G729E ................................. 22
            4.5.8   GSM ............................................. 24
            4.5.9   GSM-EFR ......................................... 27
            4.5.10  L8 .............................................. 27
            4.5.11  L16 ............................................. 27
            4.5.12  LPC ............................................. 27
            4.5.13  MPA ............................................. 28
            4.5.14  PCMA and PCMU ................................... 28
            4.5.15  QCELP ........................................... 28
            4.5.16  RED ............................................. 29
            4.5.17  VDVI ............................................ 29
   5.  Video ........................................................ 30
       5.1  CelB .................................................... 30
       5.2  JPEG .................................................... 30
       5.3  H261 .................................................... 30
       5.4  H263 .................................................... 31
       5.5  H263-1998 ............................................... 31
       5.6  MPV ..................................................... 31
       5.7  MP2T .................................................... 31
       5.8  nv ...................................................... 32
   6.  Payload Type Definitions ..................................... 32