         stopRecordingTimer()
         if audioRecorder.isRecording {
             audioRecorder.stop()
-            composer.merge(trackAt: audioRecorder.url, intoTrackAt: outputURL) {
+            composer.merge(trackAt: audioRecorder.url, intoTrackAt: outputURL, outputFileType: parentController.outputFileType) {
                 [unowned self] url, error in
                 if let error = error {
                     switch error {

    }
    
    private var newRecordingURL: URL {
        let filename = "\(UUID().uuidString).m4a"
        let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!
        return URL(fileURLWithPath: documentsPath).appendingPathComponent(filename)
    }

open class AudioRecorderController: UIViewController {
    
    open weak var delegate: AudioRecorderControllerDelegate?
    open var outputFileType: String = AVFileTypeMPEG4
    
    fileprivate let _navigationController = UINavigationController()
    fileprivate let _controller = _AudioRecorderController()
