[Live-devel] Multicast addresses for MPEG4 and H.264 streams

[Piers Hawksley]

Thanks Ross,

 >>1/ Can LIVE555 stream H.264 or MPEG4 video to rtp://<multicast 
addr>:1234 without using RTSP to set-up the stream

 >Yes, (although note that the "rtp://" URL is nonstandard, and is used 
only by (some) receivers - e.g., VLC - and has nothing to do with our 
code).  Note, though, that H.264 and MPEG-4 video streams contain 
special configuration parameters that often cause a stream to not be 
understandable by receivers, unless they get these parameters 'out of 
band' - e.g., via a SDP description.  That's why we recommend that H.264 
or MPEG-4 video streams be served via RTSP.

Thanks for clarifying - I have made an sdp file (using the response to 
the RTSP Describe message and reading RFC 4566) which I can use to 
provide the stream details to VLC.

 >>2/ Can multicast streams be received by receivers that are on a 
different subnet from the sender.

 >This depends entirely on whether your network has set up IP multicast 
routing between the sender's network and the receiver(s) network(s).  It 
has absolutely nothing to do with application-level code like LIVE555.

I was thinking that RTSP would not work if the live 555 server and the 
client (viewer) are on different subnets as the client wouldn't be able 
to reach the server. In this case an sdp file should be suitable - have 
I understood this correctly ?

 >>Is the password authentication causing a problem ?

Can RTP multicast streams have any authentication ? We use an 
authentication database with the RTSP server, but the multicast stream 
(accessed using the info in an sdp file) are freely accessible. Is it up 
to me to securely distribute the sdp file(s) or is there another way to 
secure multicast streams ?

Many thanks,

Piers