如何从Asset获取慢动作视频的文件Url？

Question

我正在获取普通视频的文件url，但慢动作视频资产类型为AVComposition。我正在尝试使用AVAssetExportSession，但它消耗了大量的时间。

PHVideoRequestOptions *options=[[PHVideoRequestOptions alloc] init];
options.version = PHVideoRequestOptionsVersionCurrent;
options.networkAccessAllowed = YES;

[[PHImageManager defaultManager] requestAVAssetForVideo:asset options:options resultHandler:^(AVAsset *avAsset, AVAudioMix *audioMix, NSDictionary *info) {

     if(([avAsset isKindOfClass:[AVComposition class]] && ((AVComposition *)avAsset).tracks.count == 2)) {

         //Output URL of the slow motion file.
         NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
         NSString *documentsDirectory = paths.firstObject;
         NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"mergeSlowMoVideo-%d.mov",arc4random() % 1000]];
         NSURL *url = [NSURL fileURLWithPath:myPathDocs];

         //Begin slow mo video export
         AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:avAsset presetName:AVAssetExportPresetHighestQuality];
         exporter.outputURL = url;
         exporter.outputFileType = AVFileTypeQuickTimeMovie;
         exporter.shouldOptimizeForNetworkUse = YES;

         [exporter exportAsynchronouslyWithCompletionHandler:^{

             dispatch_async(dispatch_get_main_queue(), ^{
                 if (exporter.status == AVAssetExportSessionStatusCompleted) {
                 }
             });
         }];
     } else if ([avAsset isKindOfClass:[AVURLAsset class]]) {
     }
 }];

Answer 1

PHImageRequestOptions.version属性的默认值为PHImageRequestOptionsVersionCurrent。

只需将版本分配给PHImageRequestOptionsVersionUnadjusted，否则PHImageRequestOptionsVersionOriginal将返回原始的慢动作视频。

PHImageRequestOptions * options = [[PHImageRequestOptions alloc] init];

options.version = PHImageRequestOptionsVersionUnadjusted;
// or 
options.version = PHImageRequestOptionsVersionOriginal;

希望这对某些人有用。