[Live-devel] openRTSP with no backchannel

[Ross Finlayson]

>I am working with a system that multicasts multiple streams over DVB-H.
>Normally, I receive an SDP file for each stream from the electronic
>service guide and I view the streams by passing the SDP file into my
>libav-based application.  However, this did not work for any of the
>streams being generated by a Mango DSP system.
>
>Enter live555.  By piping the output of openRTSP into my libav-based
>application, the video from the Mango box now pops up right away and I
>see no errors from libav. 
>
>First, thanks so much for this library.  It saved the day. 
>
>Second, please explain conceptually what live555 is doing that makes it
>possible to view the video and why I don't need it for all of our other
>streams.

Since I don't know anything about "libav" or "Mango DSP", I can't 
answer this question.

However, if you tell us the SDP description that "openRTSP" retrieves 
from the server (this is displayed as part of the diagnostic output), 
then that might give us a hint as to what's special about these 
streams.


>During this debug process, my video receiver has an ethernet
>back-channel to the server so openRTSP can negotiate the stream.
>However, in the final application, the receiver will be a mobile unit
>with no back channel.
>
>Assuming the ESG provides the same SDP file that openRTSP receives
>during its negotiation, should I still be able to write an application
>using live555 with no backchannel?

Yes, in principle.  You won't be able to use RTSP (of course), and 
this will likely work only for multicast streams, but it should work.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/