Subject: [AVT] Summary of 3GPP timed text draft

From: "Jose Rey" <[email-masked]>
Date: Mon, 7 Jul 2003 15:58:40 +0200

Hi all,

here is a quick summary of the draft and a list of the issues we want to
start discussion on in Vienna.

This draft specifies an RTP payload format for the 3GPP timed text
format. 3GPP timed text is currently only conveyed via HTTP. For
upcoming services like streaming or multimedia broadcast multicast, an
RTP payload format is needed.

The main motivation is therefore to have an RTP payload format *ready*
for Rel6 (maybe March'04, probably June'04). Envisioned areas of
application are 3GPP's MBMS (Multimedia Broadcast/Multicast Services)
and PSS (Packet Switched Services) streaming.

The open issues/TODO list includes:

- resilient transport: repetition, fragmentation, retransmission, FEC
(other?). It is our opinion that repetition should be included at the
very least.  Fragmentation is reasonable when the packets get big and
should be documented as well. Retransmission and FEC can be used, if it
makes sense for the particular use case.

- Transport of sample description information: the sample description
box (see draft for more on this) is information which is needed by many
different text samples. This amount of information might become too big
to be transported out-of-band using SDP. What are the other options?
What is the threshold to decide for in- or out-of-band transport? Should
both transport options be documented?

looking forward to the meeting in Vienna,

José Rey____ mailto:[email-masked]
Mobile Multimedia Team -  MCOM Group
Panasonic European Laboratories GmbH
Tel: +49(0)6103-766-134
Fax: +49(0)6103-766-166
http://www.pel.panasonic.de
____________________________________

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
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