[FFmpeg-user] ? About ffmpeg's prores implemention

Gary Yost gary at yostopia.com
Fri Aug 28 03:01:04 EEST 2020

’ve got a question about the Prores implementation in ffmpeg because I’ve seen some odd behavior here with FCPX (running on a very beefy 16-core Mac Pro with 192Gram and an Afterburner card).  

When I output files from ffmpeg in ProresLT format and bring them into FCPX, they stutter badly… playback is ~5fps.  But when I transcode/optimize them in FCPX, which creates Prores422 versions of those files, they play back in FCPX seamlessly.

The ffmpeg files _used_ to play back seamlessly on this machine when I was doing this Jan-March, but I haven’t been using this workflow since March.  My questions are:

1.  Is the Prores implementation in ffmpeg a 100% accurate implementation as per the Apple spec?

2.  Has anything changed in the Prores code transcoding of ffmpeg in the lat 4 months?



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