As a side note, learned today that I've been running basically zero hardware acceleration for video on linux despite having a respectable GPU. It's all been CPU and I didn't realize.

nvidia-smi dmon

is the linux command (for nvidia) - column "dec" tells you whether there is hw decode happening. This will work both for browser (youtube) and video player (mpv etc). I needed to make active changes on both to get it to actually hit the gpu. Don't assume you've got hw accel just because it is smooth

Some linux distros (e.g. fedora) don't include hw decoding for licensing reasons. I decided I wanted all the latest goodies at some point and ended up duct taping together a copr repo with mesa/ffmpeg/mpv (latest from git) with all the hw stuff enabled (though I'm probably breaking some of their rules by doing so...I've labeled it in such a way that I hope nobody comes across it and decides to use it). Anyways, my main goal with it all was to extend battery life on my laptop while watching things, it makes a pretty big difference to use proper codecs.