Re: [Freeswitch-users] Strange early media SDP behavior
It's standard SDP offer/answer. Fresswitch will not send three audio streams with three codecs. You're advertising three codecs with PCMU first. Freeswitch supports PCMU in your configuration and agrees on that codec. There are several configuration options in freeswitch and the phone that can influence this behavior. -- Kristian Kielhofner http://blog.krisk.org ----- Original Message ----- From: freeswitch-users-bounces@lists.freeswitch.org <freeswitch-users-bounces@lists.freeswitch.org> To: FreeSWITCH Users Help <freeswitch-users@lists.freeswitch.org> Sent: Sat Aug 14 11:19:07 2010 Subject: [Freeswitch-users] Strange early media SDP behavior Late negotiation is on, bypass_media=true. Leg B receives the following SDP in SIP 183 message: v=0 o=root 4913 4913 IN IP4 64.21.13.41 s=session c=IN IP4 64.21.13.41 t=0 0 m=audio 37650 RTP/AVP 0 8 18 101 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 a=fmtp:18 annexb=no a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 a=sendrecv 3 codecs in SDP offer. Freeswitch send to leg A SIP 183 with the following SDP: v=0 o=root 4913 4913 IN IP4 64.21.13.41 s=session c=IN IP4 64.21.13.41 t=0 0 m=audio 37650 RTP/AVP 0 101 a=rtpmap:0 PCMU/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - a=ptime:20 1 codec only. Why 2 other codecs are removed from SDP? Tested on today's git, older versions have the same behavior. Is it expected behavior or a bug? _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org
I would disagree, in bypass media mode FS is supposed to forward SDP as is, let endpoints to negotiate the codec. On Saturday 14 August 2010, Kristian Kielhofner wrote:
It's standard SDP offer/answer. Fresswitch will not send three audio streams with three codecs. You're advertising three codecs with PCMU first. Freeswitch supports PCMU in your configuration and agrees on that codec.
There are several configuration options in freeswitch and the phone that can influence this behavior.
-- Kristian Kielhofner http://blog.krisk.org
Also when leg B answers the call (with the same 3 codecs), FS sends 200 OK to leg A with all 3 codecs, so codecs strip happens for early media only. The problem is that leg A early_sdp differs from local_sdp and mod_sofia disables SOA support which leads to problems later, when leg A uac sends SIP session timer reinvite. On Saturday 14 August 2010, Sergey Okhapkin wrote:
I would disagree, in bypass media mode FS is supposed to forward SDP as is, let endpoints to negotiate the codec.
On Saturday 14 August 2010, Kristian Kielhofner wrote:
It's standard SDP offer/answer. Fresswitch will not send three audio streams with three codecs. You're advertising three codecs with PCMU first. Freeswitch supports PCMU in your configuration and agrees on that codec.
There are several configuration options in freeswitch and the phone that can influence this behavior.
-- Kristian Kielhofner http://blog.krisk.org
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participants (2)
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Kristian Kielhofner
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Sergey Okhapkin