Automatically set youtube video quality depending on screen size

[nk-o]

Related topic: https://wordpress.org/support/topic/control-the-resolution-of-the-background-video/#post-10203774

Related info: https://stackoverflow.com/questions/7582336/force-youtube-embed-to-start-in-720p

[CrandellWS]

bump

[MR444]

I am also interested in this feature.

Maybe also set min and max resolution. 144p is too bad for a background video but 4k+ is oversied and would slow down the user's browser performance