How to change the speed of video playback

I'm wondering if it's possible to change the video playback speed in开发者_Python百科 an iphone application. we want users to yell in the microphone to speed up the playback and get to the end.

---

You have to use setCurrentPlaybackRate:

---

There is a rate property for the AVPlayer.

If you take the example from Apple called "avPlayerDemo" in the resource section, you then simply have to set the mplayer.rate. It worked for me, I created a new slider in the xib files, implemented that slider in the AVPlayerDemoPlaybackViewController and simply set mPlayer.rate to the slider value.

---

What about the MPMoviePlayerController?

setCurrentPlaybackRate 

Here's some code which does not work at that spot

-(IBAction)abspielen:(id)sender 
{
    NSString *titleOfButton = [sender titleForState:UIControlStateNormal];
    NSBundle *bundle = [NSBundle mainBundle];
    NSString *moviePath = [bundle pathForResource:titleOfButton ofType:@"mov"];
    NSURL *movieURL = [ NSURL fileURLWithPath:moviePath];

    MPMoviePlayerController *themovie = [[MPMoviePlayerController alloc]initWithContentURL: movieURL];  
    [themovie play];
    [themovie setCurrentPlaybackRate:2.f];    
    [themovie release];

    MPMoviePlayerViewController *moviePlayer = [[MPMoviePlayerViewController alloc] initWithContentURL:movieURL];
    [self presentMoviePlayerViewControllerAnimated:moviePlayer];
    [moviePlayer release];              
}