A recent Youtube Web update has added a canvas whenever the seek bar is visible, an HTML5 canvas pops up. This was not asked for and not needed. If you disable canvases for privacy, this will cause a horrific red bad to cover half the screen until you hide the seekbar. Canvases can be used for fingerprinting, which I’m sure Google is doing here.
Yeah, I bet it would be trivial for one of their engineers to whip up a universally compatible, hardware accelerated image file converter in JS, using no external dependencies, and less than 50 lines of code. Hint: it uses Canvas