Hello Martin, Your understanding is correct. (http://www.iana.org/assignments/rtp-parameters)
If you looked at the archives of this list, you would have found the answer to your query as this issue was discussed quiet recently. Anyway, a quick recap : G729B is different from G729 and G729A in the sense that it adds the use of SID frames. Since G729 and G729A are mutually compatible, so you don't need to explicitly negotiate G729A. Specifying G729 itself in the SDP will negotiate the A flavour. annexb = yes|no determines whether it will use G729B or not. However, I also read somewhere that you can actually negotiate G729AB by specifying "G729AB" in the SDP itself. Not too sure on that though. I hope this helps. regards, Gaurav -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin van den Berg Sent: Wednesday, August 10, 2005 2:29 PM To: sip-implementors@cs.columbia.edu Subject: [Sip-implementors] G729A and G729AB As I understand it, it is not possible to *explicitly* specify G729A and G729AB in an SDP offer/answer. Instead, if the payload type is 18, G729A is offered/answered, when "fmtp:18 annexb=yes" is present in the media attributes the sender is able to receive both G729A and G729AB. Is this statement correct? Martin. -- Skype: MartinvdBerg http://sip.huisetalage.nl _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors ********************** Legal Disclaimer **************************** "This email may contain confidential and privileged material for the sole use of the intended recipient. Any unauthorized review, use or distribution by others is strictly prohibited. If you have received the message in error, please advise the sender by reply email and delete the message. Thank you." ********************************************************************** _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
