Hello, the auto-play function from the background videos of Revolution Slider does not work on mobile devices.
“In Safari on iOS (for all devices, including iPad), where the user may be on a cellular network and be charged per data unit, preload and autoplay are disabled.”
More information: https://developer.apple.com/library/safari/documentation/AudioVideo/Conceptual/Using_HTML5_Audio_Video/Device-SpecificConsiderations/Device-SpecificConsiderations.html
The same thing for Android devices.
Alternative Solution
An alternative solution for that (if the video is vital for your website) is to put a “play” button that shows a lightbox with an youtube video.
1) Upload the video on YouTube.
2) Add a caption to the revolution slider:
<a class="tp-caption btn btn-lg visible-xs visible-sm btn-primary main-button" href="http://www.youtube.com/watch?v=9d8wWcJLnFI" data-plugin-lightbox data-plugin-options='{"type":"iframe"}'
data-x="center"
data-y="center"
data-speed="800"
data-start="2500"
data-easing="Back.easeInOut"
data-endspeed="300">
Play Video
</a>
* Set the HREF with your video’s URL.