how do i record record video with avassetwriter in swift

main.swift
import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {

    var videoWriter: AVAssetWriter!
    var videoWriterInput: AVAssetWriterInput!
    var pixelBufferAdaptor: AVAssetWriterInputPixelBufferAdaptor!

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Instantiate AVAssetWriter
        do {
            videoWriter = try AVAssetWriter(outputURL: outputURL, fileType: AVFileType.mp4)
        } catch let error {
            print(error.localizedDescription)
        }

        // Set video output settings
        let videoWidth = 640
        let videoHeight = 480
        let videoSettings: [String: Any] = [
            AVVideoCodecKey: AVVideoCodecType.h264,
            AVVideoWidthKey: videoWidth,
            AVVideoHeightKey: videoHeight
        ]
        videoWriterInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: videoSettings)
        videoWriterInput.expectsMediaDataInRealTime = true

        // Add video input to the writer
        videoWriter.add(videoWriterInput)

        // Set pixel buffer adaptor settings
        let sourcePixelBufferAttributes: [String: Any] = [
            kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_32ARGB), // or kCVPixelFormatType_420YpCbCr8BiPlanarFullRange
            kCVPixelBufferWidthKey as String: videoWidth,
            kCVPixelBufferHeightKey as String: videoHeight
        ]
        pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput,
                                                                  sourcePixelBufferAttributes: sourcePixelBufferAttributes)
        // Start recording
        videoWriter.startWriting()

        // Start a session
        videoWriter.startSession(atSourceTime: CMTime.zero)
    }

    // AVCaptureVideoDataOutputSampleBufferDelegate method to handle the sample buffer
    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        if videoWriterInput.isReadyForMoreMediaData {
            // Append the sample buffer to the writer input
            let presentationTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
            pixelBufferAdaptor.append(CMSampleBufferGetImageBuffer(sampleBuffer)!, withPresentationTime: presentationTime)
        }
    }

    func stopRecording() {
        // End the session
        videoWriterInput.markAsFinished()
        videoWriter.finishWriting {
            print("Video recorded: \(self.videoWriter.outputURL.path)")
        }
    }
}
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