Comment 29 for bug 1964547

I'm using that workaround now: If I start FF with "export MOZ_DISABLE_RDD_SANDBOX=1;kstart5 firefox" from a console, I can keep video acceleration enabled and everything plays back fine again. You can also put that export in your ~/.profile file so it's applied system wide, wouldn't recommend that though as you're likely to forget about it and I understand this may translate into less security.