setupCaptureAndOutput.swift

 func setupCapture() {
        var deviceInput: AVCaptureDeviceInput!
        let videoDevice = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: .video, position: .back).devices.first
        do {
            deviceInput = try AVCaptureDeviceInput(device: videoDevice!)
        } catch {
            print("Could not create video device input: \(error)")
            return
        }
        
        session.beginConfiguration()
        session.sessionPreset = .vga640x480
        
        guard session.canAddInput(deviceInput) else {
            print("Could not add video device input to the session")
            session.commitConfiguration()
            return
        }
        session.addInput(deviceInput)
        
        do {
            try  videoDevice!.lockForConfiguration()
            let dimensions = CMVideoFormatDescriptionGetDimensions((videoDevice?.activeFormat.formatDescription)!)
            bufferSize.width = CGFloat(dimensions.width)
            bufferSize.height = CGFloat(dimensions.height)
            videoDevice!.unlockForConfiguration()
        } catch {
            print(error)
        }
        session.commitConfiguration()
    }
    
 func setupOutput() {
        let videoDataOutput = AVCaptureVideoDataOutput()
        let videoDataOutputQueue = DispatchQueue(label: "VideoDataOutput", qos: .userInitiated, attributes: [], autoreleaseFrequency: .workItem)
        
        if session.canAddOutput(videoDataOutput) {
            session.addOutput(videoDataOutput)
            videoDataOutput.alwaysDiscardsLateVideoFrames = true
            videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)]
            videoDataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
        } else {
            print("Could not add video data output to the session")
            session.commitConfiguration()
            return
        }
    }