         }
     }
     
-    private func startSession()
+    private func startPreview()
     {
         let captureSession:AVCaptureSession = AVCaptureSession()
         captureSession.sessionPreset = kSessionPreset

                self?.queue.async
                { [weak self] in
                    
                    self?.startSession()
                }
            }
            else

                previewLayer:videoPreviewLayer)
        }
        
        startSession()
    }
    
    private func startSession()
    {
        let captureDevice:AVCaptureDevice?
        
        if #available(iOS 10.0, *)
        {
            captureDevice = AVCaptureDevice.defaultDevice(
                withDeviceType:AVCaptureDeviceType.builtInWideAngleCamera,
                mediaType:kMediaType,
                position:devicePosition)
        }
        else
        {
            
        }
        
        let tryCaptureDeviceInput:AVCaptureDeviceInput?
