MPMoviePlayerController memory management

My iPad app has a main view controller that contains a MPMoviePlayerController instance variable. The actual view contains a number of numbered buttons, and when each button is pressed, I change the contentURL property of the MPMoviePlayerController to load the corresponding movie file. This works very well, but I get a memory warning. Do I need to release the previous m开发者_JAVA百科ovie file before I change the contentURL? If so, how?

MPMoviePlayerController has lot of leaks in the simulator. Deleak on device, maybe there are no leaks.