[Live-devel] What is the need of server in RTP\RTCP.

[Ross Finlayson]

>            Here I have a doubt like why exactly I need a server (Either 
> RTSP or SIP server).

In principle, two endpoints that wish to communicate don't need a separate 
'server' - **provided that** the two endpoints know, in advance, all of the 
details that they need to communicate.  I.e., if each endpoint knows - in 
advance:
         - the IP address of the other endpoint
         - the UDP port number(s) that it will be using
         - the RTP payload format(s) that will be used
         - other appropriate parameters - e.g., sampling frequency

For example, our "testMP3Streamer", "testMPEG1or2VideoStreamer" and 
"testMPEG1or2AudioVideoStreamer" test programs don't (by default) use a 
built-in RTSP server because they stream using multicast, and so the 
destination address (and other parameters) are known statically.  For 
example, the "testMP3Receiver" application is able to receive the MP3/RTP 
multicast stream from "testMP3Streamer", because the parameters of this 
stream are 'hard-wired' into it.

Most streams, however, are not this simple.  In practice, two endpoints 
that wish to communicate first need to learn the various parameters of the 
stream.  This is the purpose of the RTSP (and SIP) protocols: They are 
control protocols that are used to set up the parameters of the stream - 
using a RTSP (or SIP) server.  Once this is done, the two endpoints can 
communicate (using RTP) without involving the server at all.

>Here the scenario is different. Here main idea is getting the media 
>streams over a network. It seams to be both are same but my doubt is like 
>who will packetizing of media. Is it RTSP server or another client at the 
>other end...?

Which specific "LIVE.COM Streaming Media" application are you referring 
to?  Note that although many of the '*Streamer' applications have built-in 
RTSP servers, these servers do not handle the actual RTP data stream - they 
just help set it up.


	Ross Finlayson
	LIVE.COM
	<http://www.live.com/>