Re: [MMUSIC] Offer/Answer PT Questions

[Paul Kyzivat <[e-mail]>]

On 2/23/16 1:22 PM, Roman Shpount wrote:
> On Tue, Feb 23, 2016 at 1:04 PM, Christer Holmberg
> <[e-mail] <mailto:[e-mail]>>
> wrote:
>
>     The current rule may be easy to understand, but it's difficult to
>     understand - and that's what triggered this discussion :)
>
>     So, while we can discuss possible rules/guidelines on when a PT
>     value can be used, I still think we need to answer the first question:
>
>     - If Alice allocates PT=X for codec 1, is Bob allowed to allocate
>     PT=X for codec 2 within the same session? The current text is
>     unclear on that, and I think that is the first question we need to
>     sort out.
>
>     After that, we can discuss whether e.g. Alice at some point can
>     allocate PT=X for codec 3, and what the criteria for that is.
>
>
> As far as I can see there are 3 question/clarifications that are required:
>
> 1. PT is allocated per codec profile (codec and all associated
> parameters), not codec. For instance, if end point uses PT=100 for
> SILK/8000, it cannot reuse it for SILK/16000
>
> 2. Is PT blocked from each direction independently or both directions at
> the same time. For instance if A sent an offer with PT=100, but B never
> sent an offer or an answer with PT=100, can B sent an offer with PT=100?
>
> 3. PT reuse in sessions such as one triggered by 3pcc where it would be
> impossible to enforce PT from ever being reused.

Note that in general the 3pcc case has other issues besides PT reuse. It 
is only "simple" if we assume that everybody is using only a single 
audio session. If we get beyond that there is the matter of matching the 
number of m-lines and their media types.

So it may be that we should separate it from the others.

	Thanks,
	Paul