Hello all, Link Xie, thanks for your response: > > m=audio 10000 RTP/AVP 0 8 > > a=X-ptime: 20 30
Following Siddharth's link http://lists.cs.columbia.edu/pipermail/sip-implementors/2003-February/004556 .html It seems that from this link the answer is to use "mptime": >So instead of redefining ptime, create a new "mptime" parm that has a >construct similar to the m line: > >m=audio 49170 RTP/AVP 0 4 18 >A=mptime:10 30 30 > The packetcable spec (from http://www.packetcable.com/specifications/ ) http://www.packetcable.com/downloads/specs/PKT-SP-EC-MGCP-I06-021127.pdf also seem to use mptime: (taken from PacketCable(tm) Network-Based Call Signaling Protocol Specification) m=audio 3456 RTP/AVP 96 97 0 a=rtpmap:96 G726-32/8000 a=rtpmap:97 telephone-event/8000 a=mptime: 10 - 10 Here, rfc2833 doesn't have a packet time so it's shown with a '-' (rfc2833 is supposed to have the same packet time as the selected audio codec). Which is correct mptime or X-ptime? Regards, Attila > -----Original Message----- > From: Christian Stredicke [mailto:[EMAIL PROTECTED] > Sent: 12 March 2003 08:31 > To: 'link.xie'; 'Attila Sipos' > Cc: [EMAIL PROTECTED] > Subject: AW: [Sip-implementors] SDP packet times for muliple codecs > > > The "X-" is a bad idea. We were using this in another > scenario and many > SDP parsers complained about "x-" headers. Better use > something without > "x-" (e.g. "xptime"). > > Christian > > > -----Urspr�ngliche Nachricht----- > > Von: [EMAIL PROTECTED] > [mailto:sip-implementors- > > [EMAIL PROTECTED] Im Auftrag von link.xie > > Gesendet: Mittwoch, 12. M�rz 2003 03:46 > > An: Attila Sipos; [EMAIL PROTECTED] > > Betreff: Re: [Sip-implementors] SDP packet times for muliple codecs > > > > Hi,Attila > > I think your suggestion is wrong. We also use this solution > before. > > But we find that the meaning of 2 "m=" line repesent 2 media stream. > So > > it's not suitalbe for this case. > > Our solution is introducing a new attribut "X-mptime" > which means > > multiple ptime > > and the SDP would like: > > > > m=audio 10000 RTP/AVP 0 8 ----- 0 means g711u-law > and 8 means > > g711a-law > > a=X-ptime: 20 30 -----20 for > g711u 30 for > > g711a > > > > I think this can solve your problem > > > > Best Regard > > Link.Xie > > ----- Original Message ----- > > From: "Attila Sipos" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Tuesday, March 11, 2003 7:33 PM > > Subject: [Sip-implementors] SDP packet times for muliple codecs > > > > > > > > > > Hello everyone, > > > > > > For multiple codecs we can have an SDP like this: > > > m=audio 10000 RTP/AVP 0 8 ----- 0 means g711u-law and 8 means > > g711a-law > > > a=ptime:20 > > > But this is only correct if the packet times match for > > > u-law and a-law. > > > > > > > > > What if you have a system where, for some reason, the > > > codecs have different packet times? > > > > > > Can you do this? > > > m=audio 10000 RTP/AVP 0 - ---- g711-ulaw > > > a=ptime:20 > > > m=audio 10000 RTP/AVP 8 ---- g711 a-law > > > a=ptime:30 > > > > > > Regards, > > > > > > Attila > > > > > > <http://www.vegastream.com> > > > VegaStream : A World of difference for your Integrated > Communications > > > _______________________________________________ > > > 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
