[FFmpeg-devel] IVTC Using fieldmatch and decimate filters

Nicholas Robbins nickrobbins at yahoo.com
Mon May 5 05:33:17 CEST 2014

On Sunday, May 4, 2014 7:25 PM, Steve Boyer <steveboyer85 at gmail.com> wrote:

Hey all,
>I'm trying to encode a video, but not having luck doing a proper IVTC. I
>have compiled from source this afternoon as outlined on
>https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu. Using the command:
>ffmpeg -i 4.17.vob -map 0:1 -map 0:3 -vf crop=704:480:10:0 -vf
>fieldmatch,decimate -c:v libx264 -preset veryfast -level 41 -crf 22 -c:a
>libfdk_aac -t 360 4.17.mp4
>I result in a proper IVTC'ed video stream, but the video seems to go at an
>incorrect framerate (although running "ffmpeg -i 4.17.mp4" shows it at a
>23.976 fps). I did other versions (using -vf fieldmatch, -vf yadif, -vf
>pullup,fps=24000/1001, or -vf pullup -r 24000/1001) and the audio track
>remains in sync with the video consistently. Adding the decimate filter in
>to the mix seems to make the video play faster than the audio leading to
>the desynchronization. I see that https://trac.ffmpeg.org/ticket/3019 has
>this as fixed, but I'm still experiencing it.
>Honestly, a good IVTC solution is the ONLY thing I miss from Windows.
>I can provide samples if requested, just let me know which commands to run.
>Steven Boyer

1) What is the output of ffprobe -select_streams v -show_streams -count_frames -i

2) Are you sure it is telecined? Have you done a visual inspection of the video and seen the 3,2 P:I pattern?

Also provide the full output of your ffmpeg command.


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