Here's a transparent video that plays on top of some text, with another video as background. It's tested in both Chrome and Safari. 

The 3D video was exported with Rotato - https://rotato.xyz

Transparent video in all browsers

As you scroll on this site, the phone animates into various positions. The animation was exported as a Lottie file from the Rotato app

Cinematic Night: Scroll to animate 3D phone

As you scroll, the phone moves into various positions. The lottie animation was exported with the Rotato app (https://www.rotato.xyz)

Morten Just