Background videos playing irregularly

Hello,
I am using youtube videos in my backgrounds on the website. Unfortunately, the videos play and stop immediately on some browsers (mainly firefox and safari). Some times they work and most of the time they dont, it plays and stops.

The website link is attached. Would be grateful if i can get any help for this issue. To detect the problem, you can try running the website on different browsers.

The page I need help with: [log in to see the link]