Unable to play MP4 video file from mainBundle

So I'm trying to play a simple intro animation video file that I've dragged into my project in XCode and therefore should be able to play from my mainBundle, right?

With this code:

 NSURL *urlString = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"introvideo" ofType:@"mp4"]]; 
MPMoviePlayerController *player  = [[MPMoviePlayerController alloc] initWithContentURL:urlString];
[player play];

I get this error message: * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[NSURL initFileURLWithPath:]: nil string parameter'

Any help would be great!

This means your code can't find your introvideo.mp4 file. Make sure you have successfully add that file to your bundle. You can check in your project's setting: Copy Bundle Resource.