Hi, I don't claim to be an expert on SDP. If you don't obtain your answer here, you might want to try the mmusic email list.
For payload types which have a static number, vendors typically use the static number (unless reason to do otherwise) although I'm not aware of the related normative statements. RFC 3551 section 1 indicates "Only the binding of some of the payload formats to static payload type numbers in Tables 4 and 5 is normative"; however I doubt that it means if there is a static mapping, it MUST be used (instead of dynamic) unless altering some aspect of it (such as the PCMU example within RFC 3551 section 6). The following are a few links of potential interest. http://tools.ietf.org/html/rfc3551 http://tools.ietf.org/html/draft-ietf-mmusic-sdp-g723-g729-04 http://www.iana.org/assignments/rtp-parameters/rtp-parameters.xml http://tools.ietf.org/html/draft-ietf-mmusic-rfc4566bis-09 > -----Original Message----- > From: sampat patnaik [mailto:sam_e...@yahoo.co.in] > Sent: Wednesday, November 13, 2013 5:10 AM > To: Brett Tate > Cc: sip-implementors@lists.cs.columbia.edu > Subject: Fw: PAYLOAD TYPE FOR G729 A and G729B > > > Hi Brett, > > Can you please throw light on a query regarding the usage of PAYLOAD > TYPE in SDP media descriptor line. For G729,G729A and G729B , can you > please specify whether we can use the dynamic payload types supported > by necessary attributes i.e a parmeter that would from an RTP payload > type number (as used inan "m=" line) to an encoding name denoting the > payload format to be used. It also provides information on the clock > rate and encoding parameters. It is a media-level attribute that is > not dependent on charset. > > For Ex: > > m=audio 1564 RTP/AVP 96 8 18 97 98 > > a=rtpmap:97 G729/8000 > > a=fmtp:97 annexb=no... Can 97 be used as PT for g729a. > > > > m_e...@yahoo.co.in> wrote: > > > From: sampat patnaik <sam_e...@yahoo.co.in> > > Subject: PAYLOAD TYPE FOR G729 A and G729B > > To: "sip-implementors@lists.cs.columbia.edu" <sip- > implement...@lists.cs.columbia.edu> > > Date: Wednesday, 13 November, 2013, 12:26 AM > > Hi > > Experts, > > I > > have a query regarding this PAYLOAD type in MEDIA DESCRIPTOR > > line of SDP which goes like this .. > > As > > per IANA , the PAYLOAD type for codec type G729 is static and is > assigned as > > 18.However i would like take a confirmation on my doubt that > > the same static value is used for G729ANNEX A and G729 ANNEX > > B as well > > or it is dynamic allocation. > > Can any of our experts throw light > > on this and it would be great if u can support your reply > > along with IANA/UNIVERSAL standards of numbering > > plan. > > RegardsSam > > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
