This post covers some best free software to set video as animated desktop background in Windows. You can play a video as desktop wallpaper.
How to Set Live Wallpapers & Animated Desktop Backgrounds in Windows 10
Free Screen Recorder - Bandicam
ShareX - The best free and open source screenshot tool for Windows
How to Record My Computer Screen?
How to Make a Video Your Wallpaper in Windows 10 or 11
Open Broadcaster Software
Wallpaper Engine on Steam
Lively Wallpaper - Microsoft Apps
How to Set Animated Wallpaper in Windows 11 Free live wallpapers, Wallpaper app, Live wallpapers