[FFmpeg-devel] [PATCH 2/2] avfilter/f_interleave: reimplement on top of framesync

Stefano Sabatini stefasab at gmail.com
Fri Oct 11 14:48:39 CEST 2013

On date Friday 2013-10-11 12:12:59 +0000, Paul B Mahol encoded:
> On 10/11/13, Stefano Sabatini <stefasab at gmail.com> wrote:
> > On date Wednesday 2013-10-09 18:23:19 +0000, Paul B Mahol encoded:
> >> I can not use current state of filter to do anything useful. So it
> >> is really hard to find if something is broken.
> >
> > Please elaborate on this. The issue with stereo3d looks to me like a
> > stereo3d issue (assuming every input has a defined framerate,
> > misbehaving otherwise), or ffmpeg not liking multiple frames with the
> > same timestamps.
> I can change stereo3d filter to ignore framerate, iirc i already did this
> but I did not get expected order of frames from interleave filter.
> >
> > The other limitations are due to buffering problems, there is IMHO no
> > way to workaround them without duplicating/dropping frames.
> >
> > So I still have no evidence that there is something broken in
> > interleave (apart design issues which can't be really fixed), and I'm
> > not sure what this patch is about.
> You always mentions some 'design issues which can't be really fixed'
> but never tried to explain them or fix them or open bug report or etc....

> Do you want to confirm that current state of filter (or lavfi in general)
> is useless, as you have no control which frame from which input goes to output?

In case of interleave, it's as simple as this:

the oldest queued frame goes to output, in case there is already a
frame in all the input buffers, otherwise we queue the frame.

In some cases this can't work very well (for example if inputs doesn't
provide any frame, and you fill another queue), all which is
documented in the interleave docs.
FFmpeg = Fostering and Fast Merciless Political Ecumenical Gymnast

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