Live WP on lavender

[Akr0n]

I've just discovered that I can use a live wallpaper created by myself as stated here: http://en.miui.com/thread-5067752-1-1.html. Anyway once I've created it and putted into the right folder, when I try to set it as a wp the result is a full black static wallpaper. I can't understand why since I'm using the default theme...

EDIT: I'm using the last rn7 dev, 9.9.3 and the video is in .mp4 format