In the Youtube player, the video is too low, so it gets cut off on the bottom and there is a thin black line on the top. I've disabled all of my extensions that could affect Youtube, and it turns out Adblock is causing this. Then I disabled the subscriptions I had and figured out it was EasyList causing this problem.
I hope there is an easy way to fix this.
If it matters, I'm using the Youtube HTML5 player, Adblock 2.7.1, and Chrome 37.0.2041.4 dev-m (x64 version)
Youtube Video Too Low
Which extensions are you using?