[MPlayer-dev-eng] Re: [PATCH] dvr-ms fixes for pts, key frame detection and seeking

John Donaghy johnfdonaghy at gmail.com
Tue Feb 13 23:02:34 CET 2007

> I do have a sample that shows the AV sync issue with lavf (at least when
> it's played with "mplayer -demuxer 35") and I've uploaded it to
> ftp.mplayerhq.hu (it's called "9am with David and Kim_TEN
> Digital_09_11_2006_10_49_52.dvr-ms"). This one has video pts values on
> I-frames only.

I see that Michael has now updated the lavf demuxer to use the new
timestamps I've been talking about. I've tested this a bit and I've had
another guy, I've been helping, test it extensively on various HD samples he
has. The results seem to be perfect so far.

At this point I'm not quite sure how the lavf demuxer is taking the
intermittent timestamps (or non-chronological ones in most cases) and
turning those into something usable. But it does suggest to me that there
should be no need to parse the codec. In fact doing so probably wont work
because you need to use these dvr-ms timestamps, at least as a guide, to get
AV sync.

Regarding how to proceed, my preference at this point is to parse ahead to
get the average frame time. Then restart, and use the average to interpolate
between I-frames. But there seems to be too many objections to this approach
to make it worth my while bothering to do anything. Is there some generic
improvement required first? Can anybody suggest an acceptable way forward?

At the very least I could document all that I now know about the format in
the multi-media wiki. But how much detail should go in there?

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