Subject: [AVT] FW: I-D ACTION:draft-lennox-avt-recoverable-packets-00.txt

From: Jonathan Lennox <[email-masked]>
Date: Wed, 28 Jun 2006 20:52:52 -0400

Hello, all --

I'd like to draw the group's attention to an Internet-Draft I've submitted,
draft-lennox-avt-recoverable-packets-00.  This defines an RTP header
extension, and an AVPF feedback message, by which a subset of an RTP stream
can be marked as higher-importance and retransmitted.

The motivation is that it's possible to construct a media stream
(particularly for video) such that a you only need a small portion of the
stream to maintain long-term decoder state.  If you experience packet loss,
you can retransmit only the subportion of the stream, and then continue the
stream onward without needing full decoder state refresh.

This has proved to be very effective for video streams, particularly with
newer codecs such as H.264 that allow sophisticated inter-frame dependency
structures.  See the draft for the full details.

I'd like to request some time (20 minutes should be good) to discuss this in
Montreal, if the chairs agree. 

"Note well" disclaimer: we have some prospective IPR on this document, which
we'll license under condition of reciprocity if this is adopted as an IETF
standards-track document.  See
<https://datatracker.ietf.org/public/ipr_detail_show.cgi?&ipr_id=726>.

--
Jonathan Lennox -- Layered Media
[email-masked]

Subject: I-D ACTION:draft-lennox-avt-recoverable-packets-00.txt
From: [email-masked]
To: [email-masked]
Date: Mon, 19 Jun 2006 18:50:01 -0400

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title		: Marking and Selectively Retransmitting
High-Priority Packets in the Real-Time Transport Protocol (RTP)
	Author(s)	: J. Lennox
	Filename	: draft-lennox-avt-recoverable-packets-00.txt
	Pages		: 15
	Date		: 2006-6-19
	
In some circumstances, it is useful and desirable for the sender of
an RTP stream to be able to deliver a subset of its RTP packets
reliably.  One example of this is a video codec which can encode a
video stream such that decoder state can be maintained using just a
subset of the packets encoded.  However, existing RTP reliability
mechanisms only define mechanisms which retransmit all the packets of
an RTP stream.

This document describes a mechanism by which the sender of an RTP
stream can mark a subset of the packets of an RTP stream as high-
priority recoverable packets, and by which the receiver of the stream
can request retransmission of the high-priority packets.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-lennox-avt-recoverable-packets-00.
txt

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