I have interesting problem on Asterisk 1.4. I have video enabled, and when I make a call Asterisk sends SIP INVITE with correct media attributes in SDP for audio and video. and the called party answers with 200OK but sets “c=” field at the session-level, that is for entire session, and one more contact “c=” for video, and sets it to 0.0.0.0.
cuts from SDP in INVITE from Asterisk:
c=IN IP4 1.1.1.1
m=audio 13472 RTP/AVP 18 0 8 101
a=rtpmap:18 G729/8000
a=sendrecv
m=video 19808 RTP/AVP 99
a=rtpmap:99 H264/90000
a=sendrecv
and part from SDP of 200OK from the called server:
c=IN IP4 204.9.200.117
m=audio 60512 RTP/AVP 18 0 8 101
a=rtpmap:18 G729/8000
m=video 50000 RTP/AVP 99
c=IN IP4 0.0.0.0
a=sendonly
So, as you see the called party sets “c” for entire session and video only, but for audio it stays unclear.
When I disable video everything works fine, it is obvious.