[Live-devel] RTSP over UDP...

[Ross Finlayson]

>What you might be asking for is RTSP (over TCP) for setting up
>and controlling a streaming session with streams distributed
>in MPEG-2 TS over UDP. But that is hardly very elegant nor the right
>way to do it.

I agree.  However, this is what these set-top boxes ask for (and it's 
the only thing that they handle) - so our RTSP server implementation 
supports it.

The reason why these clients don't use RTP is that they support 
receiving MPEG Transport Streams only (not any kind of Elementary 
Stream).  MPEG Transport Streams contain their own timestamps, so 
their designers felt (rightly or wrongly) that they don't need the 
extra overhead of a RTP header in each packet.

>  And the RTSP-part of is is used to little else than downloading a sdp file.

No, they are also using the RTSP "SETUP", "PAUSE", "PLAY", and 
"GET_PARAMETER" commands.  ("PAUSE" and "PLAY" are used to do 'trick 
mode' operations; "GET_PARAMETER" is used in lieu of a RTCP "RR" 
message (keep-alive) - because there's no RTCP.)

>So they don't really support RTSP then. They just have the cabaility to
>decode MPEG-2 TS received on a given port. Correct ?

Not really.  They support a somewhat bastardized non-standard variant 
of RTSP (which we implement), but they're doing more than just 
'listening for MPEG-2 TS'.

> > Ok. I can verify that it does work with the kreatel stb's as well.
> > However, as you point out in the faq, trick play doesn't work in the
> > current edition of the library. Any chance of that patch becoming
> > available soon?

If by 'soon', you mean 'sometime later this year', then yes - I hope so.


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