Well, in any case you all don't mention DoD CELP 1016 running at 22,5 msec per frame. Do I need to rewrite the code to run at frames of 20 or 30 msec, or can I use usec in this SDP announcement? I think to use usec is the best way...
> -----Original Message----- > From: Attila Sipos <[EMAIL PROTECTED]> > To: "Christer Holmberg" <[EMAIL PROTECTED]>, > [EMAIL PROTECTED] > Cc: "link.xie" <[EMAIL PROTECTED]>, Attila Sipos > <[EMAIL PROTECTED]>, > "'Christian Stredicke'" <[EMAIL PROTECTED]>, > [EMAIL PROTECTED] > Subject: RE: [Sip-implementors] SDP packet times for muliple codecs > > > I think the problem is that (according to the rules) the ptime > attribute is not related to a specific profile but to a specific > media description: > > m=audio 10000 RTP/AVP 0 8 > > a=rtpmap: 0 PCMU/8000 > > a=ptime:20 > > a=rtpmap: 8 PCMA/8000 > > a=ptime:30 > > So I guess, officially, you can only really have one ptime parameter > associated with each "m=" line. > Personally I can't see why we couldn't use multiple packet times > in the way you suggested but maybe it'll break some implementations. > I don't know. > > As a recap, I remember the various other proposals to handle the multiple > profiles: > m=audio 10000 RTP/AVP 0 8 > a=mptime:20 30 > a=rtpmap: 0 PCMU/8000 > a=rtpmap: 8 PCMA/8000 > > or: > m=audio 10000 RTP/AVP 0 8 > a=x-ptime:20 30 > a=rtpmap: 0 PCMU/8000 > a=rtpmap: 8 PCMA/8000 > > > I have another idea: be explicit about the packet times used > for each profile (like with rtpmap): > > m=audio 10000 RTP/AVP 0 8 > a=rtpmap: 0 PCMU/8000 > a=rtpmap: 8 PCMA/8000 > a=ptimemap: 0 20 > a=ptimemap: 8 30 > > But, as you can see, it's less efficient that the mptime > or x-ptime parameters. > > > Can anyone say how far away we are before all this > "mulitple packet time" stuff is standardised? > > Attila -- Guilherme Balena Versiani ComunIP - VoIP Solutions _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
