François Beaufort revealed that Chromium team is currently working on a solution to provide smoother video frame rendering for HTML5 videos in Dev Channel.
Once you have the latest experimental Chromium build, you can try the experimental flag named “New video rendering path for video elements” by type “chrome://flags/#enable-new-video-renderer” into the browser’s address bar, press enter and restart Chrome.
In practice, that means that if your computer was on the edge of playing 4K60, 4K, 1080p60 videos on YouTube for instance (hiccup every few seconds), it should now play smoothly.
François Beaufort Google+
Issue 1083383005: Connect the new video rendering path to the compositor.