使用Objective C从Video捕获一部分帧

I am trying to develop an application like Talking Tom. I am playing a video in the UIView with MPMoviePlayerController. I got a source code for capturing UIView screen. It should work if I do not added MPMoviePlayerController. It will give a video. But if I added a MPMoviePlayerController and capture the same View, only a black screen is showing in the video. Can anyone suggest an easy way to implement this feature.I am trying to develop an application like Talk