CameraViewController.swift - init

CameraViewController.swift

var deviceInput: AVCaptureDeviceInput!

session.sessionPreset = AVCaptureSession.Preset.vga640x480

// acquire the camera device
guard let device = AVCaptureDevice
    .default(AVCaptureDevice.DeviceType.builtInWideAngleCamera,
             for: .video,
             position: AVCaptureDevice.Position.front) else {
                return
}

do {
    deviceInput = try AVCaptureDeviceInput(device: device)
    guard deviceInput != nil else {
        print("error: can't get deviceInput")
        return
    }
    
    // add the Input device to the session
    if self.session.canAddInput(deviceInput){
        self.session.addInput(deviceInput)
    }
    
    // define a Video output device to capture video frames from the camera
    videoDataOutput = AVCaptureVideoDataOutput()
    videoDataOutput.alwaysDiscardsLateVideoFrames = true
    videoDataOutputQueue = DispatchQueue(label: "VideoDataOutputQueue")
    videoDataOutput.setSampleBufferDelegate(self, queue:self.videoDataOutputQueue)
    
    if session.canAddOutput(self.videoDataOutput){
        session.addOutput(self.videoDataOutput)
    }
    
    //define a Picture output device to capture still images from the camera
    stillImageOutput = AVCapturePhotoOutput()
    
    if session.canAddOutput(stillImageOutput) {
        session.addOutput(self.stillImageOutput)
    }
    
    videoDataOutput.connection(with: .video)?.isEnabled = true
    
    // define the camera preview view
    previewLayer = AVCaptureVideoPreviewLayer(session: self.session)
    previewLayer.videoGravity = AVLayerVideoGravity.resizeAspect
    
  	// ...
    
    // and start running the capture session
    session.startRunning()
} catch let error as NSError {
    deviceInput = nil
    print("error: \(error.localizedDescription)")
}