[FFmpeg-devel] [PATCH 3/4] ffmpeg: with filter_complex, avoid random in<->out mapping.

Nicolas George nicolas.george at normalesup.org
Mon Jun 4 00:01:11 CEST 2012


Le sextidi 6 prairial, an CCXX, Nicolas George a écrit :
> I think it would be a bad idea: imagine something like that:
> 
> 	[24fps] [25fps] overlay [out]
> 
> The overlay filter is driven by its main input, so it will output 24 fps,
> and the overlay will skip a frame and stutter once per second, which may be
> acceptable. With your suggestion, the output will be selected at 25 fps, and
> thus get another round and stutter with frame duplication.
> 
> > (one could also pick the largest timebase that allows all timestamps
> >  of all inputs with same type to be exactly represented, but iam not
> >  sure this is better with actual real world data)
> 
> With an input at 24 and an input at 25, it requires time base = 1/600 and
> that is already too much for a container that only supports constant frame
> rates.
> 
> I believe using the link time base, and letting the user set the frame rate
> if necessary is the best option for now.

Pushed 1 and 2 that were approved; 4 was superseded by a better patch you
mushed in the meantime.

As for 3, I still believe it is the better solution for now. And at the very
least, the code it removes is clearly wrong.

Regards,

-- 
  Nicolas George
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