録画アプリに切り替え機能をつけたい

https://superhahnah.com/swift-avcapture-settings/
https://superhahnah.com/swift-camera-position-switching/

今、録画アプリを試しに作っているのですが。
上記の二つのサイトを使い(自分好みに少々改良)録画アプリに切り替え機能をつけたのですが、録画開始ボタンを押した時エラーが発生してしまいました。

かなり長くて申し訳ないのですが、下記のコードでどこを直せばよろしいでしょうか？

録画アプリのコード

import UIKit
import AVFoundation

class PlayVideoViewController: UIViewController, AVCaptureFileOutputRecordingDelegate{

    var captureSession: AVCaptureSession? = nil
    var previewLayer: AVCaptureVideoPreviewLayer? = nil
    
    var videoDevice: AVCaptureDevice?
    let fileOutput = AVCaptureMovieFileOutput()
    
    var reverseButton: UIButton = UIButton()
    var recordAcitnoButton = UIButton()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.black
        self.setupCaptureSession(withPosition: .back)
        self.setupPreviewLayer()
        self.setupReverseButton()
        self.zoomSlider()
        self.recordButton()
        
    }

    func setupCaptureSession(withPosition cameraPosition: AVCaptureDevice.Position) {
        self.videoDevice = AVCaptureDevice.default(AVCaptureDevice.DeviceType.builtInWideAngleCamera, for: AVMediaType.video, position: cameraPosition)
        let audioDevice: AVCaptureDevice? = AVCaptureDevice.default(for: AVMediaType.audio)

        self.captureSession = AVCaptureSession()

        // add video input to a capture session
        let videoInput = try! AVCaptureDeviceInput(device: self.videoDevice!)
        self.captureSession?.addInput(videoInput)

        let audioInput = try! AVCaptureDeviceInput(device: audioDevice!)
        captureSession?.addInput(audioInput)
        
        // add capture output
        let captureOutput: AVCaptureMovieFileOutput = AVCaptureMovieFileOutput()
        self.captureSession?.addOutput(captureOutput)

        self.fileOutput.maxRecordedDuration = CMTimeMake(value: 60, timescale: 1)
        
        captureSession?.sessionPreset = AVCaptureSession.Preset.high
        
        self.captureSession?.startRunning()
    }

    func setupPreviewLayer() {
        // camera apreview layer
        self.previewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
        self.previewLayer?.frame = self.view.bounds
        self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
        self.view.layer.addSublayer(self.previewLayer!)
    }

    func setupReverseButton() {
        // camera-reversing button
        self.reverseButton.frame = CGRect(x: 0, y: 0, width: 300, height: 70)
        self.reverseButton.center = self.view.center
        self.reverseButton.backgroundColor = UIColor.lightGray.withAlphaComponent(0.5)
        self.reverseButton.setTitle("Reverse Camera Position", for: .normal)
        self.reverseButton.setTitleColor(UIColor.white, for: .normal)
        self.reverseButton.setTitleColor(UIColor.lightGray, for: .disabled)
        self.reverseButton.addTarget(self, action: #selector(self.onTapReverseButton(sender:)), for: .touchUpInside)
        self.view.addSubview(self.reverseButton)
    }

    @objc func onTapReverseButton(sender: UIButton) {
        self.reverseCameraPosition()
    }

    func reverseCameraPosition() {
        self.captureSession?.stopRunning()
        self.captureSession?.inputs.forEach { input in
            self.captureSession?.removeInput(input)
        }
        self.captureSession?.outputs.forEach { output in
            self.captureSession?.removeOutput(output)
        }

        // prepare new camera preview
        let newCameraPosition: AVCaptureDevice.Position = self.videoDevice?.position == .front ? .back : .front
        self.setupCaptureSession(withPosition: newCameraPosition)
        let newVideoLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession!)
        newVideoLayer.frame = self.view.bounds
        newVideoLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill

        // horizontal flip
        UIView.transition(with: self.view, duration: 1.0, options: [.transitionFlipFromLeft], animations: nil, completion: { _ in
            // replace camera preview with new one
            self.view.layer.replaceSublayer(self.previewLayer!, with: newVideoLayer)
            self.previewLayer = newVideoLayer
        })
    }
    
    func zoomSlider() {
        let slider: UISlider = UISlider()
        let sliderWidth: CGFloat = self.view.bounds.width * 0.75
        let sliderHeight: CGFloat = 40
        let sliderRect: CGRect = CGRect(x: (self.view.bounds.width - sliderWidth) / 2, y: self.view.bounds.height - 80, width: sliderWidth, height: sliderHeight)
        slider.frame = sliderRect
        slider.minimumValue = 0.0
        slider.maximumValue = 1.0
        slider.value = 0.0
        slider.addTarget(self, action: #selector(self.onSliderChanged(sender:)), for: .valueChanged)
        self.view.addSubview(slider)
        
    }
    
    @objc func onSliderChanged(sender: UISlider) {
        do {
            try self.videoDevice?.lockForConfiguration()
            self.videoDevice?.ramp(
                toVideoZoomFactor: (self.videoDevice?.minAvailableVideoZoomFactor)! + CGFloat(sender.value) * ((self.videoDevice?.maxAvailableVideoZoomFactor)! - (self.videoDevice?.minAvailableVideoZoomFactor)!),
                withRate: 30.0)
            self.videoDevice?.unlockForConfiguration()
        } catch {
            print("Failed to change zoom.")
        }
    }
    
    func recordButton() {
        self.recordAcitnoButton = UIButton(frame: CGRect(x: 0, y: 0, width: 80, height: 80))
        self.recordAcitnoButton.backgroundColor = .white
        self.recordAcitnoButton.tintColor = .red
        self.recordAcitnoButton.setImage(UIImage(systemName: "video.slash.fill"), for: .normal)
        self.recordAcitnoButton.layer.masksToBounds = true
        self.recordAcitnoButton.layer.cornerRadius = 30
        self.recordAcitnoButton.layer.position = CGPoint(x: self.view.bounds.width / 2, y:self.view.bounds.height - 130)
        self.recordAcitnoButton.addTarget(self, action: #selector(self.onClickRecordButton(sender:)), for: .touchUpInside)
        self.view.addSubview(recordAcitnoButton)
       
    }
    
    @objc func onClickRecordButton(sender: UIButton) {
        if self.fileOutput.isRecording {
            // stop recording
            fileOutput.stopRecording()

            self.recordAcitnoButton.backgroundColor = .white
            self.recordAcitnoButton.tintColor = .red
            self.recordAcitnoButton.setImage(UIImage(systemName: "video.slash.fill"), for: .normal)
        } else {
            // start recording
            
            let tempDirectory: URL = URL(fileURLWithPath: NSTemporaryDirectory())
            let fileURL: URL = tempDirectory.appendingPathComponent("mytemp1.mov")
            fileOutput.startRecording(to: fileURL, recordingDelegate: self)

            self.recordAcitnoButton.backgroundColor = .red
            self.recordAcitnoButton.tintColor = .white
            self.recordAcitnoButton.setImage(UIImage(systemName: "video.fill"), for: .normal)
        }
    }
    
    
    func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
        // show alert
        let alert: UIAlertController = UIAlertController(title: "Recorded!", message: outputFileURL.absoluteString, preferredStyle:  .alert)
        let okAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil)
        alert.addAction(okAction)
        self.present(alert, animated: true, completion: nil)
    }

}