[FFmpeg-user] decimate=ppsrc question

[Paul B Mahol]

On Thu, Dec 17, 2020 at 5:16 PM Mark Filipak (ffmpeg) <markfilipak at bog.us>
wrote:

> On 12/17/2020 01:43 AM, Carl Eugen Hoyos wrote:
> >
> >
> >> Am 17.12.2020 um 06:23 schrieb Mark Filipak (ffmpeg) <
> markfilipak at bog.us>:
> >>
> >> ffmeg -i SOURCE -vf decimate=ppsrc TARGET
> >
> > The decimate filter only makes sense in a filter chain after the
> fieldmatch filter.
> >
> > Carl Eugen
>
> The source video [1] is a 24p movie with a modulo 4 frame repeat (to 30p).
>
> The command line I used:
>
> ffmpeg -i SOURCE -map 0 -vf decimate -codec:v libx265 -x265-params
> crf=16:qcomp=1.00 -codec:a copy
> -codec:s copy -dn TARGET
>
> ffmpeg did a fine job but there is still just a bit of jitter.
>
> The question is this:
> Can anyone kindly give me a usage example of this:
>

That is for cases when you process input for better frame dropping and
field matching with fieldmatch filter but do not want so much processing in
final output.
So you filter/drop frames in non-processed video using processed video,
that is why filter in that mode needs 2 inputs.
Using filter-complex is not strictly necessary to make use of that feature.