I have a 16:10 monitor, and in fullscreen, all 16:9 videos display as if they were 4:3 (there are black bars on the left and right in addition to top and bottom), so the viewing area is decreased by a significant amount. Is there any way to fix this?

I've attached an image (2nd pic) of how it looks. The first pic is the video non-fullscreened, which displays correctly.

Thanks in advance!

Probably just youtube being stupid. Happens to me too.