This isn't a request for help, this is more of a tip for users who might be seeing a Google Ad showing up at the center-footer area (assuming their theme's content area is transparent).
I recently had this issue and took to the web and found this page outlining how to do it: http://12starsmedia.com/blog/how-to-remove-ads-from-youtube-videos
Note: The directions are a little dated since YouTube menu's have upgraded since these directions were made, but I trust you'll be able to find your way as it's easier to figure out today than it was back then.
It simply instructs you to disable the ad option/feature from your YouTube channel's videos. This basically means, the only way you'll be able to disable the Google Ad is if you host the video on your personal channel and disable the Ad's yourself. Videos hosted on other channels will show Google Ad's by default, and in many cases will benefit the user if they are engaged in Ad campaigns.
Note: You'll probably want the videos to be UNLISTED since you're only using it to loop in the background.
Conclusion: If you're content area isn't transparent this issue won't concern you much, but if you're in need of a "100% Ad free looping background behind a transparent content area" this tip will be great for you.