Sound? about gpuimage HOT 9 CLOSED

[assetWriter addInput:assetWriterVideoInput];

// *****add by me  
// Add the audio input
AudioChannelLayout acl;
bzero( &acl, sizeof(acl));
acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
NSDictionary* audioOutputSettings = nil; 
audioOutputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                       [ NSNumber numberWithInt: kAudioFormatMPEG4AAC ], AVFormatIDKey,
                       [ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
                       [ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
                       [ NSNumber numberWithInt: 64000 ], AVEncoderBitRateKey,
                       [ NSData dataWithBytes: &acl length: sizeof( acl ) ], AVChannelLayoutKey,
                       nil];

AVAssetWriterInput *_audioWriterInput = [AVAssetWriterInput 
                      assetWriterInputWithMediaType: AVMediaTypeAudio 
                      outputSettings: audioOutputSettings ];

_audioWriterInput.expectsMediaDataInRealTime = YES;

[assetWriter addInput:_audioWriterInput];

movieFile = [[GPUImageMovie alloc] initWithURL:movieURL];
sepiaFilter = [[GPUImageSepiaFilter alloc] init];
[movieFile addTarget:sepiaFilter];    

movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:filteredMovieURL size:CGSizeMake(1280.0, 720.0)];
[sepiaFilter addTarget:movieWriter];

movieWriter.shouldPassthroughAudio = YES;
movieFile.audioEncodingTarget = movieWriter;
[movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

[movieWriter startRecording];
[movieFile startProcessing];

 __weak id weakSelf = self;
[movieWriter setCompletionBlock:^{
    [weakSelf finishedFilter];

}];    

[sepiaFilter removeTarget:movieWriter];
[movieWriter finishRecording];

NSArray *audioTracks = [self.asset tracksWithMediaType:AVMediaTypeAudio];