[MPlayer-users] Question about syncing a/v during playback of VDR recordings.

VDR User user.vdr at gmail.com
Thu Nov 2 18:55:36 CET 2006


Hey fellas..  First I would like to apologize if someone else has already
asked this.  If so, I'm unaware of it and nothing has been mentioned on the
VDR mailing.

Over at the VDR mailing list we're trying to resolve a long-time issue VDR
has with a/v sync during recording playback.   To get straight to the point,
what happens to the recording during playback?  Is there any repacking thats
going on?  Anything special taking place in the PES packaging layer?

Any light anyone could shed on this would be greatly appreciated.  This
problem has existed for years and never been properly addressed.  Thankfully
now there are some guys who are committed to resolving it once & for all so
any useful information anyone can offer would be welcomed with open arms!

Thanks.


Here are a couple quotes from our thread on the VDR mailing list that might
be of use:

"As far as I understand this, VDR ignores the TS-layer PCR timing data
(which, as far as I understand this, controls the raw data rate fed to
the decoders) and the syncing is done by DVB driver/firmware based on the
timing information in the underlying PES headers. Since the DVB playback
also works on PES layer and accepts data on all-you-can-eat base, I'm not
sure whether feeding the DVB device on PCR based data rates would help, or
how PCR should be forwarded to the DVB hardware."


"I'm afraid my knowledge here is too limited. If somebody can come up with
an idea of how additional timing information
should be inserted in the PES data, let's hear it.

Generally I don't think that VDR should have to to anything regarding A/V
sync during replay. It simply feeds the data to the device as fast as the
device can take it, and syncing audio and video is the device's job. Maybe
mplayer just generates additional PES headers for this?"



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