Android : Media Player - Crop Video For Fullscreen Mode

I'm using the android mediaplayer to display videos and i try to implement two modes:

The first one is a simple fullscreen mode which scales the video to the maxiumum maintainable aspect ratio. Depending on the video size there are black bars on top/bottom or left/right. The second mode should scale the video to fill the full screen but to keep the aspect ratio. That means either the width or the height has to be cropped.

And that is the problem. How to crop a video? For ImageView there is a scale type "crop_center" which crops the image on a predefined rectable. Is there a similiar solution for video? If i set the surface view to a bigger size than its parent container the surface view is automatically scaled to fill parent. Next try was to set negative margins in the parent layout but in vain. Another try was to place the surface view in a scrollview which also leads to strange behaviour. Any ideas?