Audio Sync is off on various Websites

Just a couple weeks ago I noticed that the audio sync on Facebook videos wasn't syncing properly with the video. Didn't think anything of it at first, but then I noticed this same phenomenon on various other sites including newsites, Vines, Vimeo, and YouTube, just to name a few. The audio sync appears to be fine with videos already on my system.

What's going on here? Has anybody experienced anything like this before? How can it be fixed?

Thanks!

Chris