Subject: [MMUSIC] RTSP/2.0 RTP-Info changes (draft-ietf-mmusic-rfc2326bis-14.txt)

From: Jamie Gordon <[email-masked]>
Date: Wed, 18 Apr 2007 16:51:14 +0100

I have some concerns about the changes made to the syntax of RTP-Info
in the RTSP 2.0 draft. In RTSP/1.0 it is a simple standard semi-colon
separated list of values concerning the identified URL parameter. The
newer draft changes it considerably, and I do not see any reason given
or examples illustrating the need.

Since it is far more complex, requires very specific parsers, and
completely separate code path (in case of a server supporting both 1.0
and 2.0, which one would assume will be rather common if 2.0 is to take
hold), I would like to understand the reasoning for this change, and
whether there is a simpler alternative.

Thanks,
Jamie Gordon

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From: Magnus Westerlund <[email-masked]>
Date: Thu, 19 Apr 2007 13:04:59 +0200

> whether there is a simpler alternative.

Hi Jamie,

The problem with the RTSP 1.0 RTP-Info header is that it doesn't 
indicate at all for which SSRC the information applies. Thus to address 
this and allow for synchronization information from multiple SSRCs in an 
RTP session the syntax format in the draft was specified. This as we 
need scoping in the following way. For each media stream (identified by 
URL) there can be multiple SSRCs and for each SSRC there can be multiple 
different parts of synchronization information.

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
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