All things related to multicast

[Douglas Baggett <>]

Sorry to bud into your conversaion. Been Lurking and reading. Very interesting. Does anybody know how to set up a Source Specific Multicast Stream? There is documentation on how to JOIN a SSM stream in VLC but nothing on how to make one. 

-Doug Baggett

OCI/NSF

p.s. The info on the SAP storm was HIGHLY useful. Our new router engineer here at NSF in Arlington is not on this list and was trying to figure out what was going on. I forwarded the thread which enlightened him. :)

On Jun 13, 2008, at 9:14 AM, Zenon Mousmoulas wrote:

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.