I have been having this same problem, and am also using Chrome, so I did a little research. I noticed that it wasn't just the video that was stuttering every second or so, but page scrolling as well, so it's not the video player. I opened up chrome dev tools and did some profiling and noticed that my "After the Deadline" extension was the only thing actually doing anything and it was firing a timer ever second. So, after disabling the After the Deadline extension for GiantBomb, it seems this issue has been resolved for me.
Hope that helps.