Thanks for the link. On Firefox/Linux nvidia drivers, I don't see much difference in h264 vs VP9
We don't do hardware decoding on Linux for now, because we don't do hardware acceleration for graphics by default on Linux.
Web Render might allow doing it properly, since the rendering is not on the CPU anymore.
I found this extension that forces FF to use H264 instead: https://addons.mozilla.org/en-US/firefox/addon/h264ify/
On my old MBP I'd rather consume more bandwidth than more more CPU.