[vlc-devel] [libVLC] Managing smem time needs

Rémi Denis-Courmont remi at remlab.net
Sun Jan 9 16:21:15 CET 2011


Le samedi 8 janvier 2011 15:52:17 Antonin Delpeuch, vous avez écrit :
> I'm using smem to send a stream into my application, and I'm coping with
> some latency problems.
> I'm using the duplicate module to send the stream to my program and to
> the audio output both.
> As you might know, VLC silently computes the time need for each module
> it uses. My problem is that
> the time needed by the smem module is under-estimated, since most of the
> time is spent in the callback functions,
> wich leads the stream to be outdated when it reaches the output module
> (each frame has a bad PTS).

You're using sout_duplicate in front of smem and sout_display?

If I recall an old discussion with Laurent, the real problem is that 
sout_display is really poorly designed. Among other problems, it lacks 
(re)synchronization between the stream output chain (before sout_display) and 
the elementrary stream output (after sout_display).

Laurent suggested that sout_display should re-create a complete VLC input 
object. Unfortunately, not too many people work on the stream output at the 
moment, to say the least. So sout_display was never fixed.

Rémi Denis-Courmont

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