Video Issue with Alpha Channels and Unity

Hi guys! I'm facing an issue with Unity and a format video since a while

The fact is that I want to add a video of a Girl talking into my unity VR game but as the video formats that supports Alpha channel are not compatible with Unity formats I'm unable to do it.


Do you have some experience with this? Is there a format that supports alpha channel and also is compatible with Unity?

Just as info, I'm using Adobe After Effects (Media Encoder in practice) in order to render the video.

Sincerely thanks for your answers and support!