[vlc-devel] will streaming protocols survive OR will http become the protocol of choice?!

[Ross Finlayson]

One big benefit of RTSP is that it provides a standard, 
media-type-independent language for specifying properties of the 
requested stream - in particular, where it will start (i.e., 
seeking), and the scale at which it will play (i.e. fast-forward or 
reverse play).  You can't do this usng HTTP, at least not in any 
standard way.  (Although you can sometimes do seeking using HTTP 
range queries, this works only for media types that are simple and 
uniform enough for the client to know where to seek.)

Another benefit comes from its combination with RTP/RTCP, which is 
the standard transport protocol for 'real time' media - including IP 
telephony and video conferencing.  This means that if you have an 
existing software infrastructure for delivering and/or receiving 
RTP/RTCP, then adding support for VOD etc., using RTSP, is relatively 
stratighforward.

Nonetheless, as Remi notes, the firewall/NAT unfriendliness of these 
protocols remains a major problem (but the IETF is working to 
overcome this).  It's certainly true, though, that for many 
applications, HTTP is sufficient (as sites like YouTube have demonstrated).


	Ross Finlayson
	Live Networks, Inc. (LIVE555.COM)
	<http://www.live555.com/>