[vdr] Re: A/V synchronisation

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

joachim.koenig@gmx.net wrote:
> 
> > > So when I patch the audio pts by lets say -250 ms I also
> > have to delay
> > > the transfer of that packet to the card by 250 ms.
> > Otherwise I risk that the
> > > firmware has a problem with buffering the data until it can
> > be played.
> > > But this would then be a static issue and I would not need
> > to take care
> > > of the fine adjustment because this would still be done by the card
> > > firmware.
> >
> > You are right, that should work ok. It's probably best to
> > discuss that
> > with the driver/firmware developers, they should now more details.
> 
> I assume that the driver guys do not like to have it in the driver, because
> of the required buffers. Also I think it belongs to the user application
> to provide the data at the right time.
> 
> > > 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?

I guess if you need an additional delay in the audio signal, your audio
equipment would be the place where this should be introduced.

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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