All things related to multicast

[Zenon Mousmoulas <>]

Hi Frank,

RTP payload format for H.264 video is defined in RFC3984. More  
specifically you can look at sections 8.2 and 8.3:

   An example of media representation in SDP is as follows (Baseline
   Profile, Level 3.0, some of the constraints of the Main profile may
   not be obeyed):

      m=video 49170 RTP/AVP 98
      a=rtpmap:98 H264/90000
      a=fmtp:98 profile-level-id=42A01E;
                sprop-parameter-sets=Z0IACpZTBYmI,aMljiA==

I took a H.264 video in quicktime MOV container (it's actually the  
iPhone 3G ad from apple.com) and ran it through VLC creating an SDP  
that looks like this:

v=0
o=- 1213359427288608 2 IN IP4 127.0.0.1
s=test
t=0 0
a=tool:vlc 0.8.6h
c=IN IP4 239.239.239.234/1
m=video 1232 RTP/AVP 96
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1;profile-level-id=4d401e;sprop-parameter- 
sets=J01AHqkYGoe2ANQEBAbbCte98BA=,KN4JyA==;
m=audio 1230 RTP/AVP 97
a=rtpmap:97 mpeg4-generic/44100
a=fmtp:97 streamtype=5; profile-level-id=15; mode=AAC-hbr;  
config=1210; SizeLength=13;IndexLength=3; IndexDeltaLength=3; Profile=1;

As you can see, the payload type depends on the H.264 level/profile.  
The semantics are all in there, encrypted in the RFC :)

I believe VLC does play this once it sees the SAP announcement. We can  
test it if you want (but I won't leave this running for now).

HTH,
Z.