Playing video at different speed on iOS devices?

I would like to play back a video on iPhone/iPad in the background of my game, with opengl rendered 3D on top. The video should speed up and slow down depending of the speed of the player. The video playback speed should be anything between 0 and 2 times regular speed (even faster max speed would be better, if the CPU can handle it).

Is it possible to a开发者_如何学Cdjust video playback speed like this? Also, I need to know the currently rendered video frame, so that certain events in the game can be synchronized to the video.