[vlc] Re: Cannot stream via RTSP from Bitband VOD server

[Sigmund Augdal Helberg]

On Wed, 2005-11-09 at 10:36 -0800, Ross Finlayson wrote:
> >  IMHO the stanards are in long need of a update but that is a 
> > different matter all together.
> 
> I agree.  FYI, at this very moment I'm sitting in the IETF "MMUSIC" 
> working group (the group that standardizes RTSP) meeting in 
> Vancouver.  (IETF meetings have good wireless LAN connectivity :-)  I 
> encourage anyone who is interested in updating/revising/extending the 
> RTSP standard to work with us on this.
Just putting my few cents into this discussion, both about "standard
complience" and "updating/revising/extending" the standard.

>From what I remember of the rtsp standard from when I've looked at it,
mainly before livedotcom module was added to vlc, I got the general
impression that the rtsp standard is wastly underspecified. From what I
remenber nearly all features were optional and many things were not
specified (perhaps they were "recommended"). From what I remember there
were nothing about the standard limiting one implementation from
wrapping all data in asf or another from adding most of it's features as
X-Option: headers. 

Yes, flexibility is a nice thing when it comes to a protocol, but it
seems it comes at a very high cost. My recommandation would be to create
some very cleanly defined profiles, and requiring clients and server to
announce which profiles they support. Also having a minimum profile that
all implementations MUST support would be nice.

Some sample profiles drawn from my imagination:
Baseline: Using sdp and unmuxed rtp, supporting play and stop
vod: baseline + pause and seek
trickplay: baseline + ffwd/rew

If all these profiles were cleanly specified I think we would have had a
much better basis for implementations to be interoperable.

Another thing to be considered should be automatic rollover (udp
mulitcast -> udp unicast -> tcp -> http etc). I don't really know if the
specs say anything about this.

Sigmund A. Helberg - Out of rtsp cents


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

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