Re: [MMUSIC] Proposed agenda for the joint MMUSIC/RTCWEB inteirmmeeting

"Roni Even" <> Tue, 22 January 2013 13:21 UTC

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From: "Roni Even" <>
To: "'Magnus Westerlund'" <>
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Date: Tue, 22 Jan 2013 15:18:45 +0200
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Cc: 'Cullen Jennings' <>, =?ISO-8859-1?Q?'Ari_Ker=E4nen'?= <>,, 'Gonzalo Camarillo' <>, 'Flemming Andreasen' <>,
Subject: Re: [MMUSIC] Proposed agenda for the joint MMUSIC/RTCWEB inteirmmeeting
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Hi Magnus,
Thanks, I think that the first subject is what we were also discussing in
CLUE when looking at RTP mapping and we considered the also the individual
drafts on maxssrc, and srcname.
As for the two options I am not sure that we must chose. The first one "A"
is the current practice and I agree it is under specified today.
The second on "B" depends on how we define bundle. Looking at option "B" was
suggested also for RTP mapping in CLUE (for example with regards to


-----Original Message-----
From: Magnus Westerlund [] 
Sent: 22 January, 2013 1:01 PM
To: Roni Even
Cc: 'Ted Hardie';;; 'Cullen Jennings'; 'Ari
Keränen'; 'Gonzalo Camarillo'; 'Flemming Andreasen'
Subject: Re: [MMUSIC] Proposed agenda for the joint MMUSIC/RTCWEB

On 2013-01-22 11:41, Roni Even wrote:
> Hi Magnus,
> My concern is that it is not easy to provide a proposal to a subject 
> that is not clear. I also have views about these topics but seeing no 
> requirements or use cases it is difficult to write a draft.
> I believe that the actual syntax depends on the bundle decision so any 
> work now need to assume a bundle architecture.

And I think the question of how one deals with multiple media streams in an
RTP session is an important input into the BUNDLE discussion.

> Are there any requirements for a solution even if we are looking for a 
> new way or to leverage existing mechanisms like RFC 5576.

To my understanding what we are trying to achieve is making progress into
three different subjects.

1) How multiple media streams are handled in SDP. I think there exist two
proposal from the MMUSIC discussion:
  A) One media description per RTP session and media type. Each media
     stream are identified and provided with additional information
     using stream specific parameters.

  B) Each media description is a media stream and RTP sessions are then
     expressed as Bundle of media descriptions.

2) How "Bundle" is going to be done. Which of the three proposals do we
   really believe in. Note that direction of 1) will affect how commonly
   required the usage of "Bundle" will be. Thus affect the trade-off

3) What is common relations exist between concepts in WebRTC, CLUE and other
multi-media communication contexts that needs to be identified and signalled
and at what scopes. This influences the solution for MediaStream identities,
our SRCNAME proposal in AVTEXT and CLUE work.
There are a number of commonalities here that should be considered.

> I will try to write something based on the CLUE RTP mapping draft we 
> are discussing that tries to address a similar problem as far as I

Please do, the more informed everyone is, the better.

> BTW: will these drafts be MMUSIC drafts or RTCweb?

I don't know . I think ours is likely MMUSIC. I can't answer for the other
contributions I expect. I guess the important is that all contributions are
announced to the relevant WGs.


Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVM
Ericsson AB                | Phone  +46 10 7148287
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