I need to add attribute to the video background iframe

In my website, made with upfront I have some regions. In one of them I have a iframe youtube video with a background. I need to add an attr to this iframe (data-keepplaying) but, I can't add it
can you help me?

I need this because I'm using fullpagejs plugin, and the videos are paused when I scroll on other region, I need add data-keepplaying to iframe to resolve this.
When the plugin isn't active, everything works fine.