html5 autoplay video in Mobile device

Question

Auto play is not working without muted attribute, when I try to open url in mobile device. How to play video without using muted attribute

Answer 1

I can't really make any sense of it but this managed to work on iOS Safari and Firefox (haven't tested Android):

...thing is, it only work after I set the viewport:

If anyone can actually explain why that happened, I'd really want to know. Otherwise...stay tuned for more wacky stuff :))