How to Capture Video thumbnail from video URL

Include the Following Framework in project:
AVFoundation.framework
CoreMedia.framework


- (void) CaptureThumnailImageFromVideoURl
{
// NSURL *url = [NSURL URLWithString:@"http://videos.imotors.com/videos/1onONE/1onONE_intro_new.mp4"];
NSURL *url = [NSURL URLWithString:@"http://videos.imotors.com/videos/Top200/Top200_2010_Audi_A8.mp4"];
AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
generator.appliesPreferredTrackTransform=TRUE;
[asset release];
CMTime thumbTime = CMTimeMakeWithSeconds(0,15);
AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef img, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){
if (result != AVAssetImageGeneratorSucceeded) {
NSLog(@"couldn't generate thumbnail, error:%@", error);
}
thumbImageview.image = [UIImage imageWithCGImage: img];
[generator release];
};
CGSize maxSize = CGSizeMake(100, 90); // define the size of image.
generator.maximumSize = maxSize;
[generator generateCGImagesAsynchronouslyForTimes:[NSArray arrayWithObject:[NSValue valueWithCMTime:thumbTime]] completionHandler:handler];
}