This is python script that I wrote, that generates perfect loops of Windows 95 Starfield Screensaver. Maybe it's not most performant nor best looking code, but it works good (at least @1920x1080).
Example (config: 1920x1080@30 10 sec, downscaled in ffmpeg):
You can change constants in main.py file, such as amount of stars: STARS_AMOUNT, warp speed: SPEED and other stuff, you'll understand what do what.
And then just run the file.
All requirements you can find, in requirements.txt, but its just opencv and numpy.
I wanted to turn it to .webp automatically, but some bastards realy can't accept superiority of WebP, so I left it raw (in .avi), as opencv give it to us.
But if you really want, you can convert it in any format you like with ffmpeg:
ffmpeg -i output.avi -q:v 100 out.webm
Note: FFmpeg for some reason do 100 the best quality for WebP, while for other 100 is worst and 0 is best. Also, it wouldn't show you progress on completing the ecoding of WebP, but it still do it. At least on my current version (n7.1).
PRO TIP: If you want to make wallpaper out of it (like me), you don't really need to do 1920x1080@240 60 seconds long, 1920x1080@30 for 10 seconds will do.