[mythtv] [PATCH] high speed smooth motion video

Mark Spieth mark at dclabs.com.au
Sat Feb 5 11:34:49 UTC 2005


attached is a patch that allows smooth play of video at faster than
realtime.
i.e. at audio stretch factors > 1.0
I have tested to 1.6 and works ok and is quite smooth. The effects of the
current code are quite blocky and jerky and wanted to get something for .17
that was better.
my testing is XV, non interlaced (linearblend deinterlace)
dvb 25fps on a 60Hz refresh monitor, audiotimebase.
It should be ok for videotimebase and everything else too I hope.
I believe its better than whats in there.
What it does is delete frames so that the number of frames displayed is
still 25fps. i.e 1.5x deletes 1 in 3 frames.
Everything is in AVSync except a lockout of frame rendering if it knows its
not going to be displayed (why bother) saving CPU at higher speeds.

I have a better idea that will incorporate the refresh interval as well as
the frame interval and selectively delete frames but this will take time to
figure out and wont make .17 rel.

also included is a workaround due to the effect I observed of the
audiotimecode wrapping to 0 at about 94000000 but the video one doesnt. If a
big jump is detected, audiotimecodefudge is set so that at least the faulty
recording can be viewed ok. has no impact if the recording has good
timecodes. Isaac if you want to delete that bit, just look at all the refs
to audiotimecodefudge. Mainly in AVSync.

cheers
mark
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