Re: [Ekiga-list] [OpenH323]Re: Receiving SIP RTP before media description [was ekiga answers with delay ...?]

[Damien Sandras <dsandras seconix com>]

Le dimanche 26 novembre 2006 à 23:07 +1100, Craig Southeren a écrit :
> 
> > Another limitation is that the codec to use is determined from the 200
> > OK answer in a way that is not necessarily correct.
> > 
> > For example, if you send an INVITE with iLBC, PCMU and PCMA as available
> > codecs, and the answer comes with PCMU, PCMA and iLBC (in that order)
> > back, how do you determine if you have to send iLBC or PCMU? OPAL will
> > send PCMU because it is the preferred codec in the answer.
> 
> The endpoint is free to chose any offered codec it wants. This may
> result in different codecs in each direction - this is OK and may be
> desirable in some cases.
> 

I agree with you.

However, if OPAL 1 offers PCMU, iLBC and PCMA through an INVITE, and
OPAL 2 answers with iLBC, PCMA, PCMU in the 200 OK, how does OPAL 2
determine which codec it is receiving?

It should do it using the RTP stream payload.

Currently, it will decode the stream using one of the three codecs,
which is not necessarily the one it is receiving, and it leads to
failure.

-- 
 _      Damien Sandras
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