Subject: [AVT] I-D Action:draft-ietf-avt-rapid-rtp-sync-00.txt

From: [email-masked]
Date: Wed, 8 Apr 2009 15:00:01 -0700 (PDT)

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Audio/Video Transport Working Group of the IETF.

	Title           : Rapid Synchronisation of RTP Flows
	Author(s)       : C. Perkins, T. Schierl
	Filename        : draft-ietf-avt-rapid-rtp-sync-00.txt
	Pages           : 17
	Date            : 2009-04-08

This memo outlines how RTP multimedia sessions are synchronised, and
discusses how rapidly such synchronisation can occur.  We show that
most RTP sessions can be synchronised immediately, but that the use
of video switching multipoint conference units (MCUs) or large source
specific multicast (SSM) groups can greatly increase the initial
synchronisation delay.  This increase in delay can be unacceptable to
some applications that use layered and/or multi-description codecs.

This memo updates the RTP Control Protocol (RTCP) timing rules to
reduce the initial synchronisation delay for SSM sessions.  A new
feedback packet is defined for use with the Extended RTP Profile for
RTCP-based Feedback (RTP/AVPF), allowing video switching MCUs to
rapidly request resynchronisation.  Two new RTP header extensions are
defined to allow rapid synchronisation of late joiners, and guarantee
correct timestamp based decoding order recovery for layered codecs in
the presence of clock skew.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-avt-rapid-rtp-sync-00.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the
Internet-Draft.