[FFmpeg-devel] mutlithreading in ffmpeg?

Michael Niedermayer michaelni at gmx.at
Thu Mar 31 14:51:51 CEST 2011

On Wed, Mar 30, 2011 at 03:15:48PM -0700, Thomas Worth wrote:
> >> Notice that on frame 2 (timestamp 1001), the return value from the
> >> decode function is 319, which is different from the next P frame,
> >> which is 318. Now of course we get 318 twice at PTS 2002 because
> >> ffmpeg-mt is returning the same frame twice, even though two different
> >> timestamps are specified.
> >
> > I'm afraid you have a talent for writing explanations that confuse
> > me more than they help :-)
> > I'd say what happens is just that ffmpeg(-mt) in that case decides
> > to completely drop the frame instead of "making something up" via
> > error concealment. That is probably a bug in so far as it's not supposed
> > to do that, but if your code fails with this it is too brittle.
> Sorry about that, you'll probably need to step through the code to see
> exactly what I'm talking about. Oh and by the way, you'll need to use
> an MP4 file encoded with H.264 if you decide to have a go. You can
> download a sample here, which has each frame numbered so you can see
> where threaded seek/decoding skips each frame after the keyframe:
> http://rarevision.com/ffmpeg-mt/
> There's a link to download the video:

Now, how does one reproduce this? Theres just a code snippet not a
compile able program

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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