[Freeswitch-users] Polycom G722 negotiation

Brian West brian at freeswitch.org
Fri Feb 25 19:18:02 MSK 2011

What version of FreeSWITCH are you running?


On Feb 24, 2011, at 11:45 PM, Spencer Thomason wrote:

> Hello all,
> I have several Polycom IP-650s.  On the external profile I have:
> CODECS IN        	G722,PCMU,G729,GSM
> CODECS OUT       	PCMU,G729
> On the internal profile I have
> CODECS IN        	G722,PCMU,G729,GSM
> CODECS OUT       	G722,PCMU,G729,GSM
> The Polycoms have a similar codec priority set:
> v=0
> o=- 1167611879 1167611879 IN IP4
> s=Polycom IP Phone
> c=IN IP4
> t=0 0
> a=sendrecv
> m=audio 2236 RTP/AVP 9 0 18 101
> a=rtpmap:9 G722/8000
> a=rtpmap:0 PCMU/8000
> a=rtpmap:18 G729/8000
> a=fmtp:18 annexb=yes
> a=rtpmap:101 telephone-event/8000
> The issue I have is that if I leave the internal profile to generous and a user places a call from the PSTN on hold which is PCMU, when the user tries to pick up the call, the Polycoms' preference then changes the call to G722 and there is no audio.  If I set the profile to greedy, since the call is already PCMU Freeswitch keeps it at PCMU and audio is fine.  I realize this is the intended behavior for greedy vs generous but my question is why is there no audio when switching the codecs?  I didn't want to clutter this up any more but I'm happy to provide traces however the only real difference is the codec order.
> Thanks,
> Spencer

More information about the FreeSWITCH-users mailing list