How to crop VideoOutput arbitrarily without setting clip true?

Vincent007

Is this possible with QML? The closest thing I can find is PreserveAspectCrop but I need to crop the image anywhere I like.

I found a relevant question "image cropping":http://qt-project.org/forums/viewthread/8418. However I don't prefer setting clip true, because from qt document
"Clipping is a visual effect, NOT an optimization. It increases (rather than reduces) complexity for the renderer......"