Not sure if this is what you meant, but I had the same issue (BD -> MKV file stuttering on playback on ATV4K) as OP, and disabling hardware acceleration fixed it.This, weirdly, would seem that this disable hardware decoding.
Not sure if this is what you meant, but I had the same issue (BD -> MKV file stuttering on playback on ATV4K) as OP, and disabling hardware acceleration fixed it.This, weirdly, would seem that this disable hardware decoding.