video缩略图图像不是从本地videoURL（资产URL）iOS生成的

我正在使用AVAssetImageGenerator生成video的缩略图。 当我通过本地video资产url生成图像时，它正在重新调整nil 。我使用下面的代码来生成图像。

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); 

Answer 1

使用下面的代码

 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); 

Answer 2

只需调用此方法即可创建video缩略图。

//Utilities.m

  +(void)thumbnailImageForVideoURL:(NSString *)videoURL completionHandler:(void (^)(UIImage *))completionHandler{ dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{ NSURL *url = [NSURL URLWithString:videoURL]; AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:url options:nil]; AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset]; generator.appliesPreferredTrackTransform=TRUE; CMTime thumbTime = CMTimeMakeWithSeconds(30,30); AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef im, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){ if (result != AVAssetImageGeneratorSucceeded) { NSLog(@"couldn't generate thumbnail, error:%@", error); } UIImage *image; if(im){ image = [UIImage imageWithCGImage:im]; }else{ image = [UIImage imageNamed:@"videoPlaceholder"]; } completionHandler(image); }; CGSize maxSize = CGSizeMake(568, 426); generator.maximumSize = maxSize; [generator generateCGImagesAsynchronouslyForTimes:[NSArray arrayWithObject:[NSValue valueWithCMTime:thumbTime]] completionHandler:handler]; }); } 

来自你class级的电话。

 #import "Utilities.h" [Utilities thumbnailImageForVideoURL:moviePath completionHandler:^(UIImage *thumbImage) { dispatch_async(dispatch_get_main_queue(), ^{ self.imgViewContent.image = thumbImage; //self.objectDetail.videoThumbImage = UIImageJPEGRepresentation(thumbImage, 1.0); }); }]; 

Answer 3

试试这个代码

 -(UIImage *)generateThumbImage : (NSString *)filepath{ NSURL *url = [NSURL fileURLWithPath:filepath]; UIImage *theImage = nil; AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url options:nil]; AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset]; generator.appliesPreferredTrackTransform = YES; NSError *err = NULL; CMTime time = CMTimeMake(1, 60); CGImageRef imgRef = [generator copyCGImageAtTime:time actualTime:NULL error:&err]; theImage = [[UIImage alloc] initWithCGImage:imgRef] ; CGImageRelease(imgRef); return theImage; }