[vlc-devel] Re: Problems in vlc with streams

Ross Finlayson finlayson at live.com
Thu Dec 23 00:50:03 CET 2004

>>The problem is that RTP/UDP packets from the server are not reaching your 
>>client (VLC).  Your firewall does, indeed, seem to be the problem.
>>A solution (other than fixing your firewall) is to request streaming of 
>>RTP-over-TCP.  RealPlayer (and QuickTime Player) requests this 
>>automatically (if no RTP/UDP packets are received within a short period 
>>of time).  For VLC, however, you have to set this up explicitly.
>Mmm, getting back to this...
>It would be nice if we could automate this for VLC as well of course ...
>The problem would be multicast streams which can take upto 15 seconds to 
>setup. So in this particular case, the current behaviour might be preferable.
>Ross, any ideas on this?

I wouldn't worry about the multicast case.  If a stream is multicast, then 
there's no need to consider any RTP-over-TCP alternative, because this 
makes no sense for multicast.

So, the only issue to consider is: What kind of automatic retry-over-TCP 
alternative(s) do we want to have for *unicast* streams.  I think we need 
to do something, because QuickTime Player and RealPlayer both do this.

I suggest doing the following:
1/ Setup the stream to play using regular RTP/UDP.  If no packets are 
received within N1 seconds, then:
2/ Setup the stream to play using RTP/TCP (i.e., over the RTSP TCP 
connection).  If no packets are received within N2 seconds, then:
3/ Set up the stream to play using RTP-over-HTTP, using port P1.  (Note 
that not all RTSP servers support RTP-over-HTTP.)  If this fails, then
4/ Set up the stream to play using RTP-over-HTTP, using port P2.

The values N1, N2, P1, P2 could be configurable.  Default values could be
         N1 = N2 = 5 seconds; P1 = port 80; P2 = port 8000.

If you do this, then  VLC should be able to play almost any stream from 
Darwin/QuickTime Streaming Servers, and most streams from LIVE.COM RTSP 
servers - even from behind a firewall.

As necessary, I can point you folks at the appropriate interface to the 
LIVE.COM RTSP/RTP client library to make this happen.

	Ross Finlayson

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