AFAIK, this is not valid. >From RFC3555, annexb: indicates that Annex B, voice activity detection, is used or preferred >From RFC3108, silenceSupp: indicates the use or non-use of silence suppression (The second one is less used and may not be understood by many implementations).
In your example, these two are conflicting. You should avoid sending an offer with this contradiction. But on the receive side, if you are lenient enough to accept this offer, the answer could have just a=fmtp:18 annexb=no. With this you are ensuring you take the safest approach i.e. no VAD. Regards Satya T -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Rajpal Dangi Sent: Monday, August 17, 2009 10:47 PM To: [email protected] Subject: [Sip-implementors] SDP silence suppression negotiation Hi All, While negotiating G729 codec is it valid to have "annexb=yes" and "silenceSupp:off" in the initial offer being offered assuming that far end supports all of these capabilities? For example: m=audio 8804 RTP/AVP 18 0 101 a=rtpmap:0 PCMU/8000 a=rtpmap:18 G729/8000 a=fmtp:18 annexb=yes a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=silenceSupp:off - - - -\r\n If yes, what are the possible answers from far end? Many thanks, Rajpal _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
