Create thumbnail image from video url!

I'm try to create thumbnail image from video url. I use AV Foundation Programming Guide. My project have a button and an imageview. When button pressed so thumbnail image will load on uiimageview. my code can't work,it's:

- (IBAction) btnClick : (id)sender
{

    NSURL *url = [NSURL URLWithString:@"http://www.youtube.com/watch?v=bgN62D70VLk"];

    AVURLAsset *myAsset = [[AVURLAsset alloc] initWithURL:url options:nil];

    AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:myAsset];

    Float64 durationSeconds = CMTimeGetSeconds([myAsset duration]);

    CMTime midpoint = CMTimeMakeWithSeconds(durationSeconds/2.0, 600);

    NSError *error = nil;

    CMTime actualTime;

    CGImageRef halfWayImage = [imageGenerator copyCGImageAtTime:midpoint actualTime:&actualTime error开发者_开发问答:&error];

    if (halfWayImage != NULL) {

        NSString *actualTimeString = (NSString *)CMTimeCopyDescription(NULL, actualTime);

        NSString *requestedTimeString = (NSString *)CMTimeCopyDescription(NULL, midpoint);

        NSLog(@"got halfWayImage: Asked for %@, got %@", requestedTimeString, actualTimeString);

        [actualTimeString release];

        [requestedTimeString release];

        // Do something interesting with the image.

        CGImageRelease(halfWayImage);

    }

    UIImage *image = [UIImage imageWithCGImage:halfWayImage];
    [imageView setImage:image];
    [imageGenerator release];

}

Help me for this problem,please! Thanks!

MPMoviePlayerController has some method to handle this -

thumbnailImageAtTime:timeOption:

requestThumbnailImagesAtTimes: timeOption:

cancelAllThumbnailImageRequests:

I see a few problems in your code:

• http://www.youtube.com/watch?v=bgN62D70VLk is the URL of a web page, but AVAssets must be video or audio files. Note: YouTube does not advertise the URLs of its video files.
• Your call to [myAsset duration] will block. You should instead use the AVAsynchronousKeyValueLoading protocol (see loadValuesAsynchronouslyForKeys).
• You are using halfwayImage after releasing it.

I would recommend watching the AVFoundation sessions from WWDC 2010, and looking at the session sample code.

This is very late but it will help some other who comes to this question.

Look into this answer for the same problem, Hope will help to other guys.