[MPlayer-dev-eng] r32056 Causes Loss of A/V Sync with VOB files

[Dan Oscarsson]

tor 2011-06-16 klockan 19:02 -0400 skrev Steaphan Greene:
> On 06/16/2011 03:24 PM, Steaphan Greene wrote:
> > I hope that helps someone realize what's going on.  If not, I will
> > continue to try to track it down in the code myself.
> 
> I have found the culprit, but I'm not sure what the correct solution
> really should be:
> 
> Line 2514 of mplayer.c (r33634) has:
> 
> 	sh_video->pts = pts;
> 
> ....which adjusts the video time.  When the video is the component that
> is lagging behind, this seems to just solidify the error, making it get
> worse and worse until it finally resyncs (with a seek or moving to the
> next file).  Disabling just this one line fixes my problem.
> 
> Whatever the root issue here, it seems that every 12 frames or so, my
> video is showing recalculated time-stamps that are a bit off.  If the
> above line is used, the times are then forever off every 12 frames,
> leading to serious A/V sync problems.  If this line is not used, then
> these recalculated-time frames remain close, and sync is maintained.
> 
> Perhaps this code was designed only for video that went too fast for the
> audio, and not the other way around (and thus, ptsdiff should not be
> calculated with fabs)?
> 
> If anyone has any ideas as to what I should try/test next to correctly
> solve this problem, please let me know.  I am out of my depth to try to
> correctly fix this myself, as I don't understand what it was the
> original patch was added to fix in the first place.

I think the above code was added to fix some videos with defective time
stamps.

You have not said what refresh rate you are running your display at?
If you use vo=vdpau:deint=4 I think that doubles the number of frames at
vo layer and as standard code do not drop frames at vo layer you might
get out of sync. It might work better if you do the deinterlacing at
software level. I think the current code then can do frame drops on the
deinterlaced frame rate. I had big problems when playing moves to my lcd
tv running at 24 hz because frames were not dropped, so I have patched
mplayer to take into account the vsyncs and do frame drops were needed -
and then it works fine.

   Dan