That’s significantly faster than I expected! Neat. I might guess that keyframe extraction just doesn’t parallelize well across multiple threads.
I wonder if there’s any way to speed up the jpeg encoding, too! I suspect that’s actually a majority of the CPU time now. At first glance I don’t think that’s accelerated in ffmpeg today.
As an alternative to assembling the .bif files and inserting them where Plex expects, you could instead create a wrapper around the Plex Transcoder process, altering only the JPG extraction step.
Here are some examples that do similar things:
Feature request: use ffmpeg's `-ac` flag for downmixing - #15 by imax
