Asynchronous MPMoviePlayerController load does not matter duration

I assume the method is initWithContentURL:not asynchronous. I added the following methods to do the loading in the background and then assign a temporary player to my variable.

-(void)createPlayer {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

MPMoviePlayerController *temp = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL URLWithString:@"URLString"]];

[self performSelectorOnMainThread:@selector(passPlayer:) withObject:temp waitUntilDone:YES];

[temp release];
[pool release];
}

-(void)passPlayer:(MPMoviePlayerController*)temp {    
player = [temp retain];
player.movieSourceType = MPMovieSourceTypeStreaming;
//player.view.hidden = YES;
//[self.view addSubview:player.view];
[player prepareToPlay];
}

The problem is when I print the playback time of the player, I get the following:

double duration = player.duration;
NSLog(@"duration: %f, duration);

console output:  duration: nan

I added MPMoviePlayerControllerNotificationsfor notification when a duration value is available, but even then the value is still “nan”. If I load the main thread, the duration matters, but I do not want to use the main thread, so my user interface is not blocked.

Any ideas?