Iphone 如何在iOS 6中获得压缩视频的原始音量

我使用下面的代码来压缩视频

- (void)convertVideoToLowQuailtyWithInputURL:(NSURL*)inputURL
                                   outputURL:(NSURL*)outputURL
                                     handler:(void (^)(AVAssetExportSession*))handler
{

    [[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetMediumQuality];
    exportSession.outputURL = outputURL;
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;

    [exportSession exportAsynchronouslyWithCompletionHandler:^(void)
     {

         if (exportSession.status == AVAssetExportSessionStatusCompleted)
         {

             printf("completed\n");
             NSLog(@"outputurl is %@",outputURL);

         }
         else
         {
             printf("error\n");
             NSLog(@"error is %@",exportSession.error);

         }

     }];

}

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压缩后的视频在iOS 6中声音很低，但在iOS 5中我获得了完整的原始音量，那么如何在iOS 6中获得原始音量。

iOS 6中存在一些声音问题。希望下面的URL能帮助你