无法在 iOS 13 中转换为 mp4答案

【问题标题】：Unable to convert to mp4 in iOS 13无法在 iOS 13 中转换为 mp4
【发布时间】：2019-10-16 12:21:07
【问题描述】：

在运行 iOS 13 的设备上，[exportSession exportAsynchronouslyWithCompletionHandler: 在将 .MOV 视频转换为 mp4 时总是失败并显示“操作无法完成”消息。但是，相同的代码在 13 即 12 之前的 iOS 上运行良好。我粘贴在我的完整方法下方

- (void)encodeVideo:(NSString *)videoURL
{
   // Create the asset url with the video file
    AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:[NSURL fileURLWithPath:videoURL] options:nil];
    NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];

    // Check if video is supported for conversion or not
    if ([compatiblePresets containsObject: AVAssetExportPresetLowQuality])
    {
    //Create Export session
         AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:avAsset presetName:AVAssetExportPresetLowQuality];

    //Creating temp path to save the converted video
         NSString* documentsDirectory=     [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
         NSString* myDocumentPath= [documentsDirectory stringByAppendingPathComponent:@"temp.mp4"];
         NSURL *url = [[NSURL alloc] initFileURLWithPath:myDocumentPath];

    //Check if the file already exists then remove the previous file
         if ([[NSFileManager defaultManager]fileExistsAtPath:myDocumentPath])
         {
              [[NSFileManager defaultManager]removeItemAtPath:myDocumentPath error:nil];
         }
         exportSession.outputURL = url;
         //set the output file format if you want to make it in other file format (ex .3gp)
         exportSession.outputFileType = AVFileTypeMPEG4;
         exportSession.shouldOptimizeForNetworkUse = YES;

         [exportSession exportAsynchronouslyWithCompletionHandler:^{
         switch ([exportSession status])
         {
              case AVAssetExportSessionStatusFailed:
                   NSLog(@"Export session failed");
                   break;
              case AVAssetExportSessionStatusCancelled:
                   NSLog(@"Export canceled");
                   break;
              case AVAssetExportSessionStatusCompleted:
              {
                   //Video conversion finished
                   NSLog(@"Successful!");
              }
                   break;
              default:
                   break;
          }
         }];
    }
    else
    {
           NSLog(@"Video file not supported!");
    }
}

【问题讨论】：

一直在那里尝试不同的参数。当我将 AVAssetExportPresetLowQuality 置于 if 条件下时，它没有任何区别。
你试过这个解决方案了吗？ stackoverflow.com/a/58278117/3241041
@alxlives 是的，我之前已经尝试过这个解决方案，但在我的情况下它不起作用。不过还是谢谢你的提及。

标签： ios objective-c ios13 format-conversion

【解决方案1】：

创建文件夹 -

让 filePath = documentDirectory.appendingPathComponent("FolderName")

    if !fileManager.fileExists(atPath: filePath.path) {

        do {

            try fileManager.createDirectory(atPath: filePath.path, withIntermediateDirectories: true, attributes: nil)

        } catch {

            print(error.localizedDescription)

            return nil

        }

    }

Let url =  videoURL

    destinationURL = filePath.appendingPathComponent("filename.mp4")

    url.startAccessingSecurityScopedResource()

    do {

        try  FileManager.default.copyItem(at: url, to: destinationURL)

    } catch  {

        Logging.Log.error("EncodeVideo failed \(error.localizedDescription)")

    }

    url.startAccessingSecurityScopedResource()

现在开始 Mov to MP4 工作。

【讨论】：