[vlc] RTSP client in vlc 2.1

[Gilles Chanteperdrix]

On 12/14/2013 05:50 PM, Ross Finlayson wrote:
>> Problem 1: sub-titles streaming.
>> 
>> When playing the following URL: 
>> rtsp://xenomai.org:8554/video-tests/hd-fast.mp4
>> 
>> The playback works nicely, but when enabling a sub-title track,
>> the playback suddenly stops. After inspection of the RTSP dialog,
>> here is what happens. When starting playback, vlc sends a SETUP for
>> every track, then sends a global PLAY. When the user selects a
>> sub-title track, it sends a TEARDOWN for every sub-title track,
>> then a SETUP only for the selected track. At this point live555
>> (which is what I use for the RTSP server) refuses to setup the
>> track and returns a 404 error, which causes vlc to stop playback.
> 
> 
> Unfortunately - after getting more information from Gilles, and
> thinking about this some more - I've come to the conclusion that it's
> VLC's LIVE555-interface code that's in error here, and should be
> fixed.  The basic problem that VLC (again, its LIVE555-interface
> code) should not be sending a "SETUP" for a track after it's already
> been torn down.  Most RTSP servers will not accept this, because the
> "TEARDOWN" command (according to the RTSP specification) is supposed
> to end a session.
> 
> So, rather than sending a "TEARDOWN" for all subtitle tracks, and
> then doing a subsequent "SETUP" for the subtitle track that the user
> really wants, VLC's LIVE555-interface code should instead send a
> "TEARDOWN" for all subtitle tracks *except* the one that the user
> wants (and then not send another "SETUP").  (Note that you can do
> this using the second form of the "RTSPClient::sendTeardownCommand()"
> function: the one that takes a "MediaSubsession&" as parameter.)

I had thought about that, but this will not work either, what happens if
the user wants to change the sub-title track later? You have the SETUP
after TEARDOWN issue again.

-- 
                                                                Gilles.