There are some really complicated suggestions on here, but making a video your screensaver is really easy when using xscreensaver and mpv.
View Use You Tube Video As A Screensaver
Background. What if you could be. However, if you're interested in making a youtube screensaver, use software applications that will convert youtube flash videos into screensavers.
Software Tip Create A Screensaver Youtube from i.ytimg.com
Here's what you need and how to set it up. Set youtube videos as screensaver. Bored by your static wallpaper or screensaver?
Tested on windows 7 rtm:
A) put your video into a nice trick.btw,you can also use your active wallpaper as screensaver. In this method, we use a small application named video screensaver maker that allows us to use. You remember that you're making a video screensaver that will play when you leave your mac. It is extremely easy to run your own videos as screensaver.