Answer by Praveen Dwivedi:
Set a video as your desktop wallpaper, on Windows 7 or later.
Came to know about this long back and it was pretty fascinating back then.
This can be done easily using VLC player. Open VLC and select Tools > Preferences.
On the Preferences windows, select the Video button on the left.
Under Video Settings, select DirectX video output from the Output dropdown list.
Click Save before exiting and then restart VLC.
Next, select a video and begin playing it with VLC. Right-click on the screen, select Video, then DirectX Wallpaper or by selecting Video from the Menu and clicking DirectX Wallpaper.
If you’re using Windows Aero Themes, you may get the warning message below and your theme will switch automatically to a basic theme.
Now, minimize VLC player and enjoy the show as you work.
When you are ready to switch back to your normal wallpaper, click Video, and uncheck DirectX wallpaper then close out of VLC.