[Sofia-sip-devel] question regarding codec selection by sofia-sip sdp negotiation

[Saurav SAHU]

Hi all   Which sofia-sip tag does the application use to determine the selected codec as a result of the SOA media negotiation?   In the below scenario I'm making an outgoing call from my sofia-sip application to X-Lite. The sofia-sip application sends an offer with 2 codecs in INVITE where as X-Lite responds with 5 codecs in 200 OK as the answer. The 2 common codecs are PCMU and PCMA.   Sofia-sip --------------INVITE (with SDP)---------------> X-Lite   !! sofia-cb >> nua_i_state    nua::callstate: 2    soa::active_audio: 3    nua::offer_sent: true    soa::local_sdp: v=0 o=- 3496036661568783095 7067660736617586386 IN IP4 138.198.230.172 s=- c=IN IP4 138.198.230.172 t=0 0 m=audio 8000 RTP/AVP 0 8    soa::local_sdp_str: "v=0 o=- 3496036661568783095 7067660736617586386 IN IP4 138.198.230.172 s=- c=IN IP4 138.198.230.172 t=0 0 m=audio 8000 RTP/AVP 0 8 "    ::tag_null: 0   Sofia-sip <--------------200 OK (with SDP)---------------X-Lite   !! sofia-cb >> nua_i_state    nua::callstate: 8    soa::active_audio: 3    nua::answer_recv: true    soa::remote_sdp: v=0 o=666 3042865 3047762 IN IP4 10.80.112.122 s=X-Lite c=IN IP4 10.80.112.122 t=0 0 m=audio 8000 RTP/AVP 0 8 98 97 101 a=rtpmap:0 pcmu/8000 a=rtpmap:8 pcma/8000 a=rtpmap:98 iLBC/8000 a=rtpmap:97 speex/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15    soa::remote_sdp_str: "v=0 o=666 3042865 3047762 IN IP4 10.80.112.122 s=X-Lite c=IN IP4 10.80.112.122 t=0 0 m=audio 8000 RTP/AVP 0 8 98 97 101 a=rtpmap:0 pcmu/8000 a=rtpmap:8 pcma/8000 a=rtpmap:98 iLBC/8000 a=rtpmap:97 speex/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 "    ::tag_null: 0     I am now wondering how to extract the one common codec selected by the sofia-sip stack so that I establish the media session between the 2 UA applications.     Regards Saurav