Re: [MMUSIC] BUNDLE TEXT: De-mux procedures (June 19th)

[Christer Holmberg <[e-mail]>]

Hi,

>> Using 96 for both Opus and VP8 is flat out illegal according to the RTP specs.
>
> Agree.

So, we DO agree that the usage of the *same* PT value (even if in different m= lines) for different codecs, or different codec configurations, is not allowed.

Is there some specific section in some specific RFC that can be referenced to show that?

>> The corner case where we're discussing whether one can use the same payload type is if you have two M-lines that both specify VP8, with 
>> the same codec parameters - whether they can both use 96, given that it's the same codec.
>
> Surely yes, but you lose the ability to distinguish the m= line based on the PT if you use the same PT (mapped to the exact same codec and set of codec parameters) in
> several m= lines. Some applications care about distinguishing m= lines based on PT values, and so need distinct PT values for every m= line; others don't care, and can 
> use the same PT to represent the same codec across multiple m= lines.

Exactly. So, I think it's a good idea to have some text about that in BUNDLE.

Regards,

Christer