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

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

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