14.1. Message Flow
Please pay attention to the second offer, where the client requests the server to create synthesizer resource control channel
m=audio 49170 RTP/AVP 0 96
a=rtpmap:0 pcmu/8000
a=recvonly
a=mid:1
The offer includes two RTP payload types: 0 96.
96 is in the range of dynamic payload types, therefore its description must be present in rtpmap, but it's missing. Most probably 96 should be just removed from this offer. It makes more sense in case of recognizer resource, where 96 is used for telephone-events.
Also one small suggestion:
Add normative reference to RFC3551, where RTP profile is defined (codecs, payload types,
dynamic range, e.t.c)
Regards,
Arsen Chaloyan
www.unimrcp.org