[Standards] Changing RTP codec list in Jingle?

Philipp Hancke fippo at goodadvice.pages.de
Wed Jul 6 16:55:28 UTC 2016


Am 09.06.2016 um 23:34 schrieb Jonathan Lennox:
> Does XEP-167 (or some other XEP) make it possible for a Jingle endpoint to change, or reorder, its list of supported codecs?
>
> The description-info method makes it possible to change the properties of a codec; but XEP-167 explicitly says that the order of the codecs in description-info doesn’t matter, and it doesn’t provide a mechanism to remove a codec from the list.

content-modify is another candidate but that seems to have been intended 
only for modifying the direction.

> The use case for this is the case where an endpoint can supports multiple codecs, but with a cost; so once a common codec is negotiated, it wants to remove support for other ones so that the associated decoding hardware can be freed up.
>
> This is pretty common in SIP re-INVITE messages, so this would be important for STOX Media if that’s going to be finished.
>
> Am I missing something, or is this a lacuna in Jingle?

Yeah, we are missing a description-modify message to cover this. Now do 
we have enough energy to modify 0166 and 0167 to include it?

> Do any existing endpoints support this somehow?

I doubt it. Which is surprising.


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