ios - 如何从视频中获取单个图像？

Question

我已经研究了很多关于它的代码，但我还没有找到一个可行的解决方案。我正在使用 Xcode 5.1.1 和 Iphone Retina 4inch。我想通过单击从视频中获取单个图像。之后，我将编辑图像并将效果应用于整个视频。谢谢。

更新:我出于同样的目的找到了这段代码。它也不适用于模拟器。谁能告诉我问题出在哪里？

 -(UIImage *)generateThumbImage : (NSString *)filepath
{
NSURL *url = [NSURL fileURLWithPath:filepath];

AVAsset *asset = [AVAsset assetWithURL:url];
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc]initWithAsset:asset];
CMTime time = [asset duration];
time.value = 0;
CGImageRef imageRef = [imageGenerator copyCGImageAtTime:time actualTime:NULL error:NULL];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);  // CGImageRef won't be released by ARC

return thumbnail;

Answer 1

此代码将在加载的视频中生成特定时间的图像，并将该图像从 CGImage 转换为 UIImage。

注释代码以解释其部分。

- (UIImage*)loadImage {

    AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:vidURL options:nil];

    AVAssetImageGenerator *generate = [[AVAssetImageGenerator alloc] initWithAsset:asset]; // Create object of Video. 

    NSError *err = NULL;

    CMTime time = CMTimeMake(1, 60); // Select time of 1/60ths of a second. 

    CGImageRef imgRef = [generate copyCGImageAtTime:time actualTime:NULL error:&err]; // Get Image on that time frame. 

    NSLog(@"err==%@, imageRef==%@", err, imgRef); // if something is not as expected then u can log error. 

    return [[UIImage alloc] initWithCGImage:imgRef]; // Convert Image from CGImage to UIImage so you can display it easily in a image view. 

}