How to autoplay videos on Firefox

It’s been a couple of weeks since I switched to Firefox because I want to support The Open Internet and Mozilla says it’s an ethical browser. Even though, being ethical or not, I don’t agree with the idea of Google controlling every corner of the web. So after switching I noticed something that really itched me instantly: opening autoplayed videos pages in new tab doesn’t autoplay. In Chrome autplay videos do not auplay until the tab is in foreground or active.