Thanks.

I got mpv compiled by others and the question has been solved.

{
     PPA: https://launchpad.net/~mc3man/+archive/ … onic-media
     sudo apt install mpv
}

(Video Transcode / Re-encode to higher frame rate)

#### log:

20:29:48.471: ===== Starting mpv ======
20:29:48.471: Command line: /usr/bin/mpv /home/xycadmin/Video/test.mp4 -o /home/xycadmin/Video/test.SVP.VO.mkv --no-audio --no-sub --no-sub-auto --input-ipc-server=/tmp/mpvencodesocket --input-media-keys=no --no-msg-color --vf=vapoursynth:/home/xycadmin/.local/share/SVP4/scripts/ffff.py:4:3 --ofps 60.000 --ovc=libx264 --ovcopts=preset=slow,crf=18,threads=3

#### :end

Then, nothing happened but failed.