Re: [MMUSIC] POF/PAN: SDP group attribute in a POF/PAN?

On Mon, Oct 21, 2013 at 3:29 PM, Paul Kyzivat <pkyzivat@alum.mit.edu> wrote:

> On 10/21/13 5:53 PM, John Leslie wrote:
>
>> Paul Kyzivat <pkyzivat@alum.mit.edu> wrote:
>>
>>>
>>> There remains the problem of indicating *which* (if any) group a newly
>>> added m-line joins.
>>>
>>
>>     Not only don't I see an _answer_ to this -- I don't even think we have
>> a common understanding of the _question_.
>>
>>     :^(
>>
>
> Here is an example:
>
> a=group:bundle A B
> a=group:bundle C D
> m=audio ...
> a=mid:A
> m=audio ...
> a=mid:B
> m=video ...
> m=mid:C
> m=video ...
> a=mid:D
>
> Then we do a POF
>
> m=video ...
> a=mid:E
>
> We want to add this to the 2nd bundle. How do we say that?
> I'm suggesting:
>
> m=video ...
> a=mid:E
> a=groupref:bundle C
>
> The only a=group that matches that is the second one, so this implicitly
> updates that one to:
>
> a=group:bundle C D E
>
> Make sense? Its all a hack of course. But everything that is done to SDP
> is a hack.
>

I think even this case can break if you use FEC based grouping mechanism

a=group:FEC-XR a b c
a=group:FEC-XR a d

now if we want to add the new "mid e" to the list where i have mid a listed
, we end up at the same point.

How about  we can extend groupref to include the entire group line as below

m=video ...
a=mid:E
a=groupref:FEC-XR a d

==> this would end up as
a=group:FEC-XR a b c
a=group:FEC-XR a d e   // new one added to the right line

>
>         Thanks,
>         Paul
>
>
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