Video VideoClip with alpha on a plane

I can't figure it out how to implement a video with alpha channel in unity for mobile devices (Until now I used EasyMovieTexture plugin).
It seems that my possibilities are:

1- create a MovieTexture blending in a single file the RGB and the alpha mask. But it doesn't work on mobile
2- using the new VideoClip component and a webm file with transparent background. But I can only attach the video on a camera, I need to put it on a plane in a Augmented Reality scene.
3- using a chromakey shader with EasyMovieTexture, but my videos have not a flat alpha color, the different transparency of the green makes the final result a bit ugly.

The VideoClip seemed to be the solution, but I cannot understand why is limited to the cameras...
Any alternative solution?

 

i used after adobe effects to key out the green screen in a .mov video, exported it with the alpha again as a .mov file to adobe premiere that supports a very cool plugin that creates webm (https://github.com/fnordware/AdobeWebM), applied that to a plane and it works like a charm. not sure about the mobile devices part

 

@telferman, I used the plugin in Premiere, exported a webm file with V8 and vorbis, and I'm able to apply it to a cube, but I'm getting a black texture behind the video, instead of a transparent video. I too can apply it to a camera, and it's transparent... but I've tried applying with video player to a quad, cube, and plane... all produce the below result;

 

Did you figure out this problem? I'm having the same issue

 

My solution was to create a custom shader with Amplify. I made the half the video the color channel and half the video the alpha channel. Hope this helps!