MPMoviePlayerViewController quits unexpectedly - iphone

Question

I'm trying to get videos to play from my server on the iPhone device. I'm using the following method to do so, however, it only works in the simulator; and on my iPhone 4. It doesn't work on iPhone 3G?
If I call this method on the iPhone 3G, it opens the video modal screen, starts to load the video, and then closes the modal screen abruptly. No errors are shown in the console.
The iPhone 3G has version 4.0 installed. My iPhone 4 has version 4.1.
Has anyone else experienced this?
-(IBAction)playMedia{
NSString* url = [self.data objectForKey:#"url"];
//initialize the movie player
self.moviePlayerViewController = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL URLWithString:url]];
//show a background image while the user waits
moviePlayerViewController.view.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"background.png"]];
moviePlayerViewController.moviePlayer.movieSourceType = MPMovieSourceTypeFile;
//show the movie
[self presentMoviePlayerViewControllerAnimated:moviePlayerViewController];
[moviePlayerViewController release];
}

Answer 1

ok I got video to work on both iPhone 4 and iPhone 3G. Basically the issue was the file format. I was playing a .mov file. When I changed the format to .mp4, it now works on both devices. No change in code.
Hope this helps others with the same issue.

Answer 2

I'd do the above a little differently:
-(IBAction)playMedia{
NSString* url = [self.data objectForKey:#"url"];
//initialize the movie player
MPMoviePlayerViewController *tmpPlayer = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL URLWithString:url]];
self.moviePlayerViewController = tmpPlayer;
//show a background image while the user waits
UIColor *tmpColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"background.png"]];
self.moviePlayerViewController.view.backgroundColor = tmpColor;
self.moviePlayerViewController.moviePlayer.movieSourceType = MPMovieSourceTypeFile;
//show the movie
[self presentMoviePlayerViewControllerAnimated:self.moviePlayerViewController];
[tmpPlayer release];
[tmpColor release];
}