小编ish*_*nwa的帖子

我正在获取普通视频的文件 url，但慢动作视频资产类型是AVComposition. 我正在尝试AVAssetExportSession但它消耗大量时间。

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 …