Re: [MMUSIC] M-lines: Wikifying it

Harald Alvestrand <> Tue, 04 December 2012 09:22 UTC

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Date: Tue, 04 Dec 2012 10:22:45 +0100
From: Harald Alvestrand <>
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Subject: Re: [MMUSIC] M-lines: Wikifying it
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On 12/03/2012 06:18 PM, Christer Holmberg wrote:
> Hi,
>>>>>>>>> So, the exercise is NOT about how to apply attributes to individual sources?
>>>>>>>> Only in the sense that it is about figuring out which attributes need to be applied to individual sources.
>>>>>>> Well, I believe that was my original question :)
>>>>>>> If you want to apply an attribute to an individual source, you must use the ssrc attribute.
>>>>>> If you are in the camp that believes that there should be more than oneindependent source per M-line.
>>>>>> That camp seemed to me to be in the minority in Atlanta; it was absolutely not the consensus opinion.
>>>>> It's not about in which camp someone is, it's about the assumptions we make in the wiki study. If the assumption is one source per m- line, than I think it should be explicitly stated.
>>>>> Trying again, since I'm obviously not making myself clear:
>>>> The two alternative approaches are:
>>>> - Everything that needs to be controlled separately is in its own M-line. Everything that needs to go on the same RTP session uses BUNDLE to get there. Transport parameters get figured out somehow.
>>>> - Everything that goes on the same RTP session goes on the same M-line.
>>>> Due to backwards compatible SDP, we may choose to use BUNDLE to lump video and audio together - or we may choose MMT if that works for people. Anything that needs separate control uses a=ssrc.
>>> Exactly!
>>> So, which (if any) approach do you assume in the wiki? :)
>> For the 5th time: I'm NOT assuming one or the other approach.
>> I'm trying to gather information that people can use to decide which approach to follow.
>> That REQUIRES that the wiki does NOT assume one approach.
>> Do you hear me now?
> So, coming back to my original question: For "F", a *stream* refers to an individual source (and is not related to whether one m- line will or will not contain multiple sources). Correct?
I don't want to mix in the "source" word (CLUE has talked about sources 
that originate multiple streams enough to confuse that term), but if you 
want to think in terms of sources, yes.

> Regards,
> Christer