获取视频缩略图之AVAssetImageGenerator

将之前的获取视频帧的方法回顾总结一下:

方式一:获取相关帧集

AVURLAsset *urlSet = [[AVURLAsset alloc]initWithURL:url options:nil];

AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc]initWithAsset:urlSet];

generator.appliesPreferredTrackTransform = YES;

NSLog(@"generator = %@",generator);

CMTime time = CMTimeMake(1, 30);

AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){

UIImage *thumbImg = [UIImage imageWithCGImage:image];

if (result == AVAssetImageGeneratorSucceeded) {//成功即显示

dispatch_async(dispatch_get_main_queue(), ^{

cell.imageView.image = thumbImg;

cell.tags = 1;

});

}

};

generator.maximumSize = CGSizeMake(200, 200);

[generator generateCGImagesAsynchronouslyForTimes:

[NSArray arrayWithObject:[NSValue valueWithCMTime:time]] completionHandler:handler];

方式二:得到某时刻帧特征图片       容易获取失败

AVAsset *urlSet = [AVAsset assetWithURL:url];

AVAssetImageGenerator *gener = [[AVAssetImageGenerator alloc]initWithAsset:urlSet];

CMTime actualTime;

CGImageRef imageRef = [gener copyCGImageAtTime:CMTimeMakeWithSeconds(1, 10) actualTime:&actualTime error:nil];

CMTimeShow(actualTime);

/////这里的nserror需判断是否为nil,不为nil返回

NSString *key = [_cameraFilesArr[indexPath.row] componentsSeparatedByString:@"."][0];

dispatch_async(dispatch_get_main_queue(), ^{

UIImage *thumbImg = [UIImage imageWithCGImage:imageRef];

cell.imageView.image = thumbImg;

[_imgCache setObject:thumbImg forKey:key];  // 缓存

});