[vdr] Re: A/V synchronisation

[joachim.koenig@gmx.net]

> > > > Am I correct with this assumption? This would of course
> > > invent a delay
> > > > buffer
> > > > for audio into vdr (and to make it flexible we would need
> > > to do it for video
> > > > also).
> > >
> > > Replay and transfer modes use ringbuffers anyway. You only
> > > have to split
> > > it into video and audio buffers. The play thread the needs to
> > > be smart
> > > about fetching from the right buffer depending on timestamp
> > > +/- delay. I
> > > did that in an old version of the DVD patch. It worked ok and
> > > the logic
> > > behind it is not that complex.
> > 
> > Ok, then it seems not so difficult to implement. Klaus, what do
> > you think about it ? Is this something for release 1.3 ? 
> 
> VDR handles "correct" data streams and delivers them "correctly".
> I wouldn't want to have all the extra overhead of buffering 
> audio and video
> separately just to generate a then basicly "incorrect" data stream.
> Besides, that still wouldn't work with live video, would it?

Of course VDR handles correct data streams. But keep in mind that there is 
as life behind the DVB card. When you connect a beamer or 100HZ TV or
a AC3 decoder or anything else in the video and/or audio path it will
put additional delay on video and/or audio. This will results in a
a/v sync problem. You only can solve this at the source of the chain.
I'm not asking to play or make incorrect streams, just to be flexible 
with the a/v delay. Besides, there are many DVDs and SVCDs out with 
incorrect a/v sync where this would also help (of course those streams 
are in a way "broken").
As I said, I do not ask for the implementation, but for a discussion
of the issue. I can (and will) implement it for myself if needed.

This will not work for live video. With the new firmware we may use
transfer mode even for live vide. This would also enable us to stop 
the live video as some STBs already offer. 

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