ios - 不是从本地视频URL( Assets URL)iOS生成的视频缩略图

我正在使用 AVAssetImageGenerator 生成视频的缩略图。当我通过本地视频资产网址生成图像时，它正在重新调整 nil 。我正在使用以下代码生成图像。

 NSURL *url = [NSURL fileURLWithPath:filepath];

AVAsset *asset = [AVAsset assetWithURL:url];
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc]initWithAsset:asset];
CMTime time =CMTimeMake(1, 1);

CGImageRef imageRef = [imageGenerator copyCGImageAtTime:time actualTime:NULL error:NULL];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

最佳答案

使用以下代码

AVAsset *asset = [AVAsset assetWithURL:url];
    //  Get thumbnail at the very start of the video
    CMTime thumbnailTime = [asset duration];
    thumbnailTime.value = 0;

    //  Get image from the video at the given time
    AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];

    CGImageRef imageRef = [imageGenerator copyCGImageAtTime:thumbnailTime actualTime:NULL error:NULL];

    UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef);