Real-time Transport Protocol (RTP) Payload Format for Enhanced AC-3 (E-AC-3) Audio
RFC 4598

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>, 
    avt mailing list <avt@ietf.org>, 
    avt chair <avt-chairs@tools.ietf.org>
Subject: Protocol Action: 'RTP Payload Format for E-AC-3 Audio' 
         to Proposed Standard 

The IESG has approved the following document:

- 'RTP Payload Format for E-AC-3 Audio '
   <draft-ietf-avt-rtp-eac3-02.txt> as a Proposed Standard

This document is the product of the Audio/Video Transport Working Group. 

The IESG contact persons are Cullen Jennings and Jon Peterson.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-eac3-02.txt

* Technical Summary

This document describes an RTP payload format for transporting
Enhanced AC-3 (E-AC-3) encoded audio data. E-AC-3 is a high 
quality, multichannel audio coding format and is an extension of the AC-3
audio coding format, which is used in US HDTV, DVD, cable and
satellite television and other media. E-AC-3 is an optional audio
format in US and world-wide digital television and high definition
DVD formats. The RTP payload format as presented in this document
includes support for data fragmentation.


* Working Group Summary

This is a straight forward RTP payload format, similar to previous
formats. It has been reviewed by the AVT working group, and is not
controversial.

* Protocol Quality

This document was reviewed in detail by Colin Perkins and Magnus
Westerlund.

Note to RFC Editor
 
In section 7 please replace

Old:
   E-AC-3 encoders may use a range of bit rates to encode audio data, so
   it is possible to adapt network bandwidth by adjusting the encoder
   bit rate in real time or by having multiple copies of content encoded
   at different bit rates.  Additionally, packing more frames in each
   RTP payload can reduce the number of packets sent and hence the
   overhead from IP/UDP/RTP headers, at the expense of increased delay
   and reduced error robustness against packet losses.

New:
   Because it is possible to vary the bit rate used by an E-AC-3 encoder,
   it is possible to use a variety of techniques to adapt to network 
   bandwidth.

IESG Note
  
   (none)