[popcornmix]

It seems like the ffmpeg4 performance regression was fixed only for 8-bit HEVC. There is still a performance decrease with 10-bit HEVC.
I tested builds #0424 and #0531 with jellyfish-10-mbps-hd-hevc-10bit.mkv.
Build #0424: 7-8 skipped frames.
Build #0531: 11-12 skipped frames.

I find the skipped frame counts to be quite variable. Are you sure these measurements are repeatable over multiple runs?
It feels like they are within the normal variation.

(Note: the act of bringing up the OSD tends to cause some skips when it caches characters for a new font. We also report the skips/drops on playback end in the debug log. Do you see the same results there?)