[FFmpeg-user] Detelecine: I got the right result from the wrong command?

[Alex Xu]

When I said, "doesn't matter" I meant that the issue of duplicated frames
174+175 and skipped 173. Yes, I understand that incorrectly specifying the
fps can cause other issues though.

Anyways, I tried:

ffmpeg -i detelecine_input.mkv -vf
"fieldmatch,decimate,drawtext=fontfile=Arial.ttf: text='%{frame_num}':
start_number=0: x=(w-tw)/2: y=h-(2*lh): fontcolor=black: fontsize=20:
box=1: boxcolor=white: boxborderw=5" -c:v libx264 -crf 18 -c:a aac -b:a
192k -pix_fmt yuv420p fieldmatch_decimate_only_no_r.mkv

the issue of duplicated frames 174+175 and skipped 173.

In case you missed it, my test file was in the first message of the chain.
And using the detelecine filter got me the right result (with wrong params?)

On Wed, May 28, 2025 at 3:54 PM Mark Filipak <markfilipak.imdb at gmail.com>
wrote:

> On 28/05/2025 18.46, Alex Xu wrote:
> > I put it there since it was in Huspnet's original command.
>
> Ahem!
>
> > I don't think it
> > matters,
>
> Of course it matters. You're taking 30/1.001fps, detelecining to
> 24/1.001fps, then telling FFmpeg to
> make 24fps from it. Of course, every 1000th frame is repeated.
>
> > same problem occurs if I omit it or use -r 24000/1001 instead.
>
> I think you must be fuddled.
>
> Your command should be
> ffmpeg -i <input> -vf fieldmatch,decimate -map 0 -c <encoder> <output>
>
>
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