Responsive background video for the site, how best to proceed?

Question

HTML

Good afternoon, I ran into a problem, I'm making a background video for the site, it goes like a screensaver to the site at some points, I use the html5 flow player, the task is to optimize this video for the site, since now some browsers are slowing down.
I also wanted to know if I need to add a few more videos, how best to optimize them for the site?
We also decided to load different videos for different devices to avoid overload and more or less optimization.
This is the first time I've come across a video for the site, I'll be glad for any advice) Thank you for your time.

Answer 1

You can, for example, lower the resolution of the video, and apply an effect like here minko.io so that the pixels are not visible.

Answer 2

No, the problem itself is its optimization, I do it professionally once, so I would like to know the professional subtleties in this matter.