[mythtv] RE: Super speed playback bug

[Bruce Markey]

COFFMAN Steven wrote:
> Ok, nope, they're encoded wrong. Mplayer plays the files with video and sound progressively farther out of sync. Maybe this is the bug that got fixed in CVS a while ago.

Steve, this has been a known symptom for quite some time and
it is a problem during recording. What can happen is that if
the CPU is too busy, the backend fails to grab all the frames
from the capture card in time (i.e. Lucy in the chocolate
factory). Therefore, the file may have significantly fewer
than 30 frames per second (25fps, PAL) but the player still
believes it should play a frame every 1/30th of a second. It
tries to compensate by making adjustments based on the time
codes but if there are more than a few frames missing a tug
of war ensues.

The two leading causes are setting the resolution too high
for your system/signal quality. Or, other CPU intense
processes running while you are recording. See:

http://www.mythtv.org/docs/mythtv-HOWTO-19.html#ss19.4

The amount of CPU can vary quite a bit depending on how much
motion is in the show and/or how much noise is in the signal.
If you're near the 10% idle mark, some shows may be okay while
others go completely screwy. Try bumping the resolution down
a notch and save some disk space while you're at it =).

Of course, if you compile on a machine while you are recording,
playback of that recording isn't going to work so well even at
low res.

--  bjm