Subject:
RTP payload types
From:
"ahmet uyar" <auyar@csit.fsu.edu>
Date:
Sat, 31 Mar 2001 17:08:32 -0500
To:
"Geoffrey Fox" <fox@csit.fsu.edu>

There is a field on RTP header which specifies the payload type. there is an internet draft called "RTP Profile for Audio and Video Conferences with Minimal Control" which assignes payload type numbers to encoding algorithms. So from the payload type, it is possible to know which algorithm is used to encode  the audio or video on the RTP package. then if the client knows how to decode that information, it should be able to play the audio or video sent.
 
I do not know whether people stick with those numbers or they use some other numbers..
 
One more thing, there are also some encoding algorithms for which a payload type number is not assigned such as G.723. it is claimed that there is no two interoperable G.723 implementations.
 
The Internet draft is at: http://www.ietf.org/internet-drafts/draft-ietf-avt-profile-new-10.txt
 
Ahmet Uyar