[nSLUG] ffmpeg sync issues

Herb htheriault at gmail.com
Tue Nov 13 16:59:35 AST 2007


I'm running 1gb ram and the data is going from one 7200rpm disc to
another on an AMD 64 2800+ (32bit os) preemtible kernel. Only other
thing I have running at the time is firefox.

Ran a few more tests with the svn ffmpeg that I compiled and although
it complained a few times about being out of sync, it seems to have
been resolved on the fly without dropping frames. So not too sure
what's up yet.

Going to check out the scripts from the link above as well.

Thanks!

-Herb

On Nov 13, 2007 3:59 PM, Rich <budman85 at eastlink.ca> wrote:
>
>
>
>  Ian Campbell wrote:
>
>  On Sun, Nov 11, 2007 at 10:06:57AM -0400, Herb wrote:
>
>
>  Anyone here having issues with video falling out of sync when using
> ffmpeg? There is evidence of it on various groups, but no one is
> offering up any possible reasons or solutions.
>
> I'm trying to build a dvd of short clips from various sources, some of
> which I'm editing in kino before exporting as a vob. Export from kino
> works fine but converting to dv, or any other format, using ffmpeg
> drops the video out of sync.
>
>  It may depend on what kind of mangling you or ffmpeg are doing to the
> video. Deinterlacing or IVTC can cause synching problems depending on
> how they're done... should only happen if the framerate changes, but
> I'm sure there are other possible causes.
>
>
>  Thinking about hardware... how much RAM do you have free, as well as where
> you are reading and writing.
>  If you have two hard drives, on separate controllers, try reading from one
> and writing to another.
>  Its possible the hardware is having issues trying to stream and decode
> while writing.
>
>  I setup a work share on my fastest drives - this works fine, I hardly get
> sync errors.
>  Also, try dropping some apps while decoding, especially the resource
> hungry.  If you system starts to swap,
>  while decoding, that could be where you seeing the sync issues.
>
>
>  Rich
>
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