Autoplay Video Not Working on Safari Mobile Devices

Hey guys,

So autoplay video seems to work on Chrome for desktop and mobile and Safari on desktop, but not Safari on mobile. I did read that autoplay videos might not work on all browsers; however, people on Safari are are served a thumbnail of the video with a play button that doesn't actually work.

I'm not using a poster image, but if I did will that replace the thumbnail image that people see when using Safari on mobile?

Thanks