+ (UIImage*) thumbnailImageForVideo:(NSURL *)videoURL atTime:(NSTimeInterval)time { AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];

NSParameterAssert(asset);

　　AVAssetImageGenerator *assetImageGenerator =[[AVAssetImageGenerator alloc] initWithAsset:asset];

assetImageGenerator.appliesPreferredTrackTransform = YES;

　　 assetImageGenerator.apertureMode = AVAssetImageGeneratorApertureModeEncodedPixels;

CGImageRef thumbnailImageRef = NULL;

　　CFTimeInterval thumbnailImageTime = time;

　　NSError *thumbnailImageGenerationError = nil;

　　 thumbnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumbnailImageTime, 60)actualTime:NULL error:&thumbnailImageGenerationError];

　　if(!thumbnailImageRef)

　　 NSLog(@"thumbnailImageGenerationError %@",thumbnailImageGenerationError);

　　 UIImage*thumbnailImage = thumbnailImageRef ? [[UIImage alloc]initWithCGImage: thumbnailImageRef] : nil;

　　　　return thumbnailImage;

}

iOS開發之視頻根據url獲取第一幀圖片,獲取任一幀圖片