Re: [rtcweb] Fwd: I-D Action: draft-alvestrand-one-rtp-00.txt

[Paul Kyzivat <[e-mail]>]

On 8/11/11 7:32 AM, Harald Alvestrand wrote:
> I have taken some of the information I learned from the discussions in
> Quebec City about the issues of putting video and audio into the same
> RTP session and created a draft from them outlining a solution to the
> problem of signalling this configuration using SDP.
>
> Comments welcome, including the recommended context for processing the
> document; in a few days I'll send the same note to AVTCORE and/or MMUSIC.

Harald,

A few questions/comments:

1) If ICE is being used, how do you expect it to be handled on the 2nd 
m-line? Since one of the goals of multiplexing on a single rtp session 
is to minimize ICE processing, one would hope only to do ICE on the 
first of the grouped m-lines. But if the answerer doesn't support this 
grouping, then the ICE will be needed on the others.

2) The draft only shows this mechanism being used to combine one audio 
and one video. Do you also imagine it being used to represent multiple 
audio and/or multiple video streams that might otherwise be handled 
independently? (I see no reason why it couldn't be used that way.) This 
would allow description of different properties for each one.

3) In the example, for an entity that doesn't understand TOGETHER, you 
still show the a=mid lines. This is appropriate for an answerer that 
*does* understand a=group. However an answerer that doesn't implement 
rfc3388 would presumably omit the a=mid lines from the answer. So the 
offerer had better be prepared for that as well.

	Thanks,
	Paul