Making GTK graphics offloading work
GTK recently introduced the ability to offload graphics rendering, but it needs rather recent everything to work well for offloading video decoding.
So, what do you need to make sure this works?
First, you of course need a video to test. On a modern desktop computer, you want a 4k 60fps video or better to have something that pushes your CPU to the limits so you know when it doesn’t work. Of course, the recommendation has to be Big Buck Bunny at the highest of qualities – be aware that the most excellent 4000×2250 @ 60fps encoding is 850MB. On my Intel TigerLake, that occasionally drops frames when I play that with software decoding, and I can definitely hear the fan turn on. When selecting a video file, keep in mind that the format matters.