Subject: [clue] Fwd: RE: [MMUSIC] Another bundling proposal (and why you can't neglect RTP)

From: Paul Kyzivat <[email-masked]>
Date: Sun, 24 Feb 2013 02:36:09 -0500

Roni, Jonathan, and anybody else who cares:

There is continued discussion over in MMUSIC about the bundling 
approach, as well as now bundled things are demultiplexed.
Much of that discussion is being driven by rtcweb, but clearly to 
affects clue as well.

If we had a multiplexing scheme over RTP that could be correlated to an 
m-line within a bundle without being based on either SSRC or payload 
type, would that be sufficient for both our static and dynamic mappings? 
(So that we would not need the RTP header extensions.)

The main limitation I see is that I don't see how this can accommodate 
indicating a single RTP stream as satisfying multiple capture-encodings. 
I'm also not sure how important that is.

	Thanks,
	Paul

-------- Original Message --------
Subject: 	RE: [MMUSIC] Another bundling proposal (and why you can't
neglect RTP)
Date: 	Sat, 23 Feb 2013 23:14:17 -0800
From: 	Bernard Aboba <[email-masked]>
To: 	Paul Kyzivat <[email-masked]>, "[email-masked]"
<[email-masked]>

Paul said:

  > I had originally found little reason to pursue
  > draft-westerlund-avtcore-transport-multiplexing-04, but now I start to
  > think that this provides an answer to the problem of demuxing without
  > having to specify SSRCs or restrict payload types. I think it could be
  > used, rather than an RTP header extension, to specify capture-encodings
  > for clue. (But it can't specify mapping to multiple capture-encodings.)

[BA] Yes, I've also begun to wonder if we haven't been giving that (and
possibly)
other transport multiplexing approaches insufficient consideration.  A/V
multiplexing isn't just an SDP issue, it is also an RTP issue.  Say we don't
specify SSRCs and instead require that the payload type is unique among
all multiplexed m= lines so we can use PT to de-multiplex incoming RTP.
Without specifying SSRCs, how do we map the RTCP reports, which
only include SSRCs and not payload types to the appropriate media
stream tracks?   It seems to me that Cullen's "Plan A" has a fundamental
flaw.