parallax site with scrolling video background?

[hoja]

I would like to create a site with scrolling, auto-playing full width video, without playback controls – this seems not to be possible with inbuilt means.
Did anyone get a script to run which plays a video on desktop computers and serves a still frame on mobile devices?

Here's such a script, shared at Github – but I failed figuring out how exactly (and if at all) the manual code insertation to the page body works...



Btw if a developer is reading this: Is making a native option for scrolling bg video planned?