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

Uoti Urpala uoti.urpala at pp1.inet.fi
Wed Feb 28 23:31:07 CET 2007

On Wed, 2007-02-28 at 11:55 -0600, John Donaghy wrote:
> I've got a prototype build of the asf demuxer now that plays HD dvr-ms fies
> ok except in the occasional situation where there is a significant jump in
> the timestamps between 2 video frames. This only appears to be happening in

About 0.4 seconds as in your example or are there bigger ones?

> progressive ATSC recordings at the end of a commercial break. At this point
> the AV sync goes out and doesnt recover. Below are some timestamps from a
> sample I have.

If the audio timestamps are "inconsistent" in the sense that pts
difference to the next packet does not match the number of audio samples
from the packet at the indicated output frequency then sync can be lost
temporarily. However it should recover in a few seconds from pts jumps
of below 0.5 s. Any such desync caused by whatever effects in the past
should recover as long as the future timestamps are correct (unless you
explicitly disable adjustment mechanisms with -mc 0 for example).

If it stays out of sync what does the status line show? If the A-V value
stays close to 0 then the most likely reason for the desync is that
you're returning bad timestamps (which tell the rest of MPlayer to play
video and audio with that offset).

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