[FFmpeg-user] Confusion about fieldmatch, decimate and framerate (now with yadif)
Carl Eugen Hoyos
cehoyos at ag.or.at
Sun Nov 10 05:52:32 CET 2013
Nicholas Robbins <nickrobbins <at> yahoo.com> writes:
> Ok, on my current sample. I checked the length and
> framecount using ffmpeg, getting: Frames: 169698
> Duration: 1:34:19.29 for a frame rate of 29.97.
I apparently miscalculated, sorry.
> In the encode, I get this quite a bit:
> "Frame #328307 at 10954.5 is still interlaced" So I think,
> I should add> in yadif=deint=interlaced as per
> http://ffmpeg.org/ffmpeg-filters.html#Examples-37 between
> the fieldmatch and the decimate.
Sounds correct and reasonable to me.
> ffmpeg -i in.mkv -vf libx264 -crf 17 -preset veryfast
> -vf "fps=30000/10001,fieldmatch,yadif=deint=interlaced,decimate"
> However, the resulting file is visually the same.
Did you extract the offending frame as fieldmatch outputs
it and compared it with the same frame as output by
Every other test is meaningless.
> So I check with
> ffprobe -show_frames -select_streams v out.mkv | grep interlaced_frame=1
This tests something else which is 100% unrelated
(and which you should really ignore / forget if
you are interested in inverse telecine, there is
no real world stream that sets this the way you
> I guess fieldmatch doesn't mark the frames it can't
> deal with. It just leaves them where they are.
This would be a serious bug, if you can actually reproduce it,
please upload the five-ten relevant frames.
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