[vdr] Re: Lip-Synchronisation

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

Gregor Lawatscheck wrote:
> 
>  >I know its not the fault of VDR when this problem occurs, but it would be
> great >to have the possibility to synch the current video.
> 
> >Would it be possible to know how does the firmware synchronize audio and
> >video (PTS ?, DTS ?, other ?)
> 
> I've been wondering the same thing too and have PTS handling on the list of
> "bugs" I'd like to fix (if I had the expertise and time) / see fixed in vdr
> because the PTS handling could possibly introduce probs with unclean streams.
> 
> According to Metzler on the DVB list it's PTS the full featured cards use
> to sync A/V. It would certainly help if vdr would write PTS correctly in
> remux.c (used for transfermode / recording). This way after a stream
> reception error sync remux wouldn't be needed? As far as I can see vdr is
> treating PTS in a different way (or not at all?) than mpegtools' ts2ps
> does. ts2ps applies timestamps to the header according to a coded-in
> transformation table if I read the code correctly -- vdr doesn't do this.
> 
> Now possibly this is because it's not needed for "pseudo" TS coming from a
> full card -- but then what about real TS with recording from a budget card
> or using transfer mode? I'm not quire sure what the reasoning behind it
> is... I'm sure Klaus can comment much more competently than myself...

VDR doesn't do anything with or about PTS, since it simply writes the
data as delivered from the DVB card to disk (with some re-packing).
That data stream is supposed to be playable just as it is, since that's
what the DVB card would have played in live mode, too.

However, if somebody can come up with some reasonable things to do with the
PTS, let's see it.

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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