Subject: [AVT] Updated issues to discuss -- draft-ietf-avt-rtp-h264-01.txt

From: Stephan Wenger <[email-masked]>
Date: Thu, 13 Mar 2003 16:38:25 +0700

Folks,
here is an updated list of the issues re the H.264/JVT packetization.  It 
reflects mostly the discussions here in Pattaya, where MPEG and JVT 
currently meets:

Unchanged items:
1. Status of JVT -- should be out for the final ballot by the time of the 
meeting.
2. Fragmentation -- we decided on adding application layer fragmentation of 
NALUs to support some exotic scenarios.  I plan to describe the pros and 
cons of the fragmentation, and hope for more guidance from the meeting re 
these feature.  We had discussed this briefly in Atlanta already, but it 
has turned out that I forgot some applications where fragmentation is useful.
3. MIME/SDP sections: are they ok?
4. Interaction with MPEG-4 simple packetization (since H.264 is also 
ISO/IEC 14496-10).  Miska and I are currently in Pattaya at the JVT/MPEG 
meeting, as are Jan Van-der-Meer, Dave Singer, Young-Kown Lim (and other 
knowledgeable people).  We will have some discussions about the interaction 
of the two drafts, and report probably to the mailing list, but certainly 
orally at the meeting, about the outcome of these discussions.
5. I currently believe that the problem mentioned in section 12 of the 
draft doesn't exist, but we will discuss this here in Pattaya as well and 
take action as necessary.
6. Security section seems to need more work, but this is not reflected in 
the draft yet.  We plan to present a summary of the problems and proposed 
solution if there is time left.

New items:
7. Interoperability between MPEG-4 simple and H.264 packetization -- as it 
has turned out, we already have one common operation point.  Now that AUs 
are syntactically defined in MPEG-4, we can add something similar to a STAP 
that adds another common operation point.  Our goal is to make this draft a 
binary-compatible superset of the MP4-Simple draft when carrying H.264, but 
it is unclear whether this can be achieved.
8. MIME/SDP codepoints to support out-of-level picture sizes -- the video 
conferencing industry needs to support extreme picture sizes (e.g. 1500 x 
1000 pels) at low frame rates, for example for document cameras.  However, 
they don't want to signal a profile/level combination that allows for this 
picture size (memory requirements), because that also implies the ability 
to decode high speed bit streams at high frame rates (computational 
requirements).  Such codepoints are in principle agreed in the ITU-T H.245 
protocol, and we are asked to add similar codepoints in the MIME/SDP.
9. I will be prepared to explain DON (why it is there, and it works), but 
we admit that there is an urgent need for clearer language for both.

Regards,
Stephan

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Audio/Video Transport Working Group
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