[linux-dvb] Re: AW: Re: VDR and DVD with pause -> noise corrupt

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

Andreas Schultz wrote:
> 
> Ralph Metzler wrote:
> > Klaus Schmidinger writes:
> >  > Ralph Metzler wrote:
> >  > >
> >  > > Klaus Schmidinger writes:
> >  > >  > If the audio frames don't contain a PTS, it's no wonder they get out of sync
> >  > >  > (even in normal replay video and audio gets out of sync after some time).
> >  > >
> >  > > They should not any longer after my last firmware syncing patch
> >  > > about 10 days ago. This patch no longer was a workaround for the
> >  > > "jerking picture bug", which would just sync audio/video at the start
> >  > > of playback, but a complete fix. Syncing is always on now.
> >  >
> >  > I just replayed a DVD with the latest versions of both driver and VDR,
> >  > but after a while video and audio ran out of sync (audio was about half
> >  > a second early). I'm not talking about external AC3 replay, but "internal"
> >  > replay of both audio and video via the DVB card (converted by the 'ac3dec'
> >  > that comes with VDR).
> >  >
> >  > Do others also experience this, or is it just me?
> >  >
> >  > >  > Is there a way to have ac3dec generate the necessary PTS for the audio frames?
> >  > >  > The original Dolby Digital frames that ac3dec uses to generate the "normal"
> >  > >  > audio frames must, I believe, contain a PTS, don't they?
> >  > >
> >  > > Of course they contain the correct PTS but reinserting it would not
> >  > > help because the decoder hardware does not support syncing for PCM sound.
> >
> >
> > But you were talking about "normal replay" which I understood to mean
> > normal MPEG2 video and MPEG audio.
> > As I already wrote above, there is no syncing if using PCM. So, I am not
> > surprised that sync is lost.
> > Or does your ac3dec convert to MPEG audio? If it does, does it insert
> > the proper PTSs?
> 
> As far as i understand, it generates LPCM frames. I experimented with
> copying the PTS from the original AC3 frame, but that totaly messed up
> the output.
> 
> Andreas

So I would assume that there _is_ some sort of syncing attempt, but maybe the
PTS just were not correct? Maybe the LPCM frames need interpolated PTS?

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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