Attila, I've researched the archives and found you had similar discussions last year, but it appears there are questions still unanswered. Maybe you guys resolved them in some other form. 1. Where is the use of mptime defined? I looked at the PacketCable docs referenced at some threads and couldn't find it there. 2. How is the rfc2283 packet time presented if rfc2283 is listed in the "m=" line? 3. The most important question. Can somebody definitely say that based on RFC3264 and RFC2327 one can not use more than one "a=ptime" line? The following is a question from Christer Holmberg which was left unanswered in your previous thread and is exactly my question as well: "Which "rules" are you refering to? RFC2327 does say ptime is a media attribute, but I can't find anywhere said that you can't specify separate values for specific codecs (using it together with rtpmap)."
I am surprised the SIP community would leave this unaddressed for such a long time? Regards, Danail Kirov -----Original Message----- From: Attila Sipos [mailto:[EMAIL PROTECTED] Sent: Tuesday, November 02, 2004 1:05 AM To: Danail Kirov; Linda Xiao; [EMAIL PROTECTED] Subject: RE: [Sip-implementors] Does RFC3264 allow different ptime for different audio codecs? This is still an officially unaddressed problem (and I really don't understand why). We (and some others) support the mptime or (x-mptime) attribute. So your list would get compressed to: m=audio 5004 RTP/AVP 0 4 18 a=rtpmap:0 PCMU/8000 a=mptime:10 30 20 Some use x-mptime instead of mptime: a=x-mptime:10 30 20 We allow for both. Regards, Attila Software Engineer http://www.vegastream.com/ -----Original Message----- From: [EMAIL PROTECTED] on behalf of Danail Kirov Sent: Tue 02/11/2004 00:51 To: 'Linda Xiao'; [EMAIL PROTECTED] Cc: Subject: RE: [Sip-implementors] Does RFC3264 allow different ptime for different audio codecs? The problem with this approach is that I can not specify what is my codec preference 0, 4 or 18 - i.e all of them are equal. Also with this approach the "answerer" may choose to accept all "m=" streams and to start sending audio data on all 3 of them...while I really want a single audio stream. -----Original Message----- From: Linda Xiao [mailto:[EMAIL PROTECTED] Sent: Monday, November 01, 2004 4:30 PM To: 'Danail Kirov'; [EMAIL PROTECTED] Subject: RE: [Sip-implementors] Does RFC3264 allow different ptime for dif ferent audio codecs? I think you can (or should) use multi-line of "m=". m=audio 5004 RTP/AVP 0 a=rtpmap:0 PCMU/8000 a=ptime:10 m=audio 5004 RTP/AVP 4 a=rtpmap:4 G723/8000 a=ptime:30 m=audio 5004 RTP/AVP 18 a=rtpmap:18 G729/8000 a=ptime:20 Regards/Linda -----Original Message----- From: Danail Kirov [mailto:[EMAIL PROTECTED] Sent: Monday, November 01, 2004 4:14 PM To: [EMAIL PROTECTED] Subject: [Sip-implementors] Does RFC3264 allow different ptime for different audio codecs? Hi All, Is it allowed to add a=ptime:xx for every codec listed in a single m= line? For example: m=audio 5004 RTP/AVP 0 4 18 a=rtpmap:0 PCMU/8000 a=ptime:10 a=rtpmap:4 G723/8000 a=ptime:30 a=rtpmap:18 G729/8000 a=ptime:20 All the samples I've seen so far imply there is only one ptime per m= line, but this does not describe the "real world" where one would want to use different audio codecs with different packet times and different codecs operate on different [ms] frames. G.711 - 1ms G.729 - 10ms G.723 - 30ms i.e - specifiying 10ms does not make any sense for G.723, but does for G.729 and G.711. Regards, Danail Kirov _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
