I have the Plex app running on a Mi Box with Android 6.

I cannot work out why, but some videos will be played back at several times the correct speed. Maybe 4x or 8x faster? The sound keeps running at the correct speed though.

Many other videos play back fine, though.

I can't see anything odd about the videos that trigger the issue -- they include x264 and hevc files, at 720p and 1080p resolutions. All were 23.98hz (film framerate).

I have many other files which match those same parameters though, which play back fine.

The "bad" videos play back fine in Plex on Windows, and they also play back fine in Kodi on Android TV.

I tried re-encoding one of the videos, with ffmpeg, converting it from x264 to hevc in the process, but the problem persisted.

It's almost like there's metadata on the file saying it needs to play back at a very wrong high framerate except that everything I read on the metadata says 23.98 as expected.

I don't suppose anyone else has seen this problem, or even better, has found a fix?