Sane YouTube FPS on FireFox on OpenBSD

One thing I really want to be able to do is to load YouTube and put it in background as my work music. On OpenBSD the playback performance is a meh. Espically on Chromium. Opening a 720p 60FPS YouTube video yeilds ~10% frame drop in YouTube stats. Beyond that, the actual rendering rate feels more like 15 FPS. I tried different flags in Chromium but nothing seemed to boost it back to 60FPS. I turned back to Firefox and it was better then Chromium immediately. At ~5% frame drop and a much better real rendering rate.

And so I looked into about:support and about:config and to figure out how can I make GPU acceleration work. FireFox GPU acceleration works on Linux. And OpenBSD borrows Linux's display stack and uses the same X11 architecture. There's hope that I can make it work.

Messing around with flags does work! This probably weakens some security. But heck. It's still much better and what I got on Linux. Now the support page shows I'm using GPU. Just a screenshot to prove it works:

To be specific, I changed the following flags:

gfx.webgpu.force-enabled                       : true
gfx.webrender.compositor.force-enabled         : true
gfx.x11-egl.force-enabled                      : true
layers.acceleration.force-enabled              : true
gfx.webrender.all                              : true

After these changes. Scrolling on comlicated pages become much more responsive (almost as smooth as on Linux!). And YouTube playback now is almost perfect.