Hold Button to record a video with AVFoundation, Swift 3

Question

I am trying to figure out how to record a video using AVFoundation in Swift. I have got as far as creating a custom camera but I only figured out how to take still pictures with it and I can't figure out how to record video. Hope you can help me figure this one out.

I want to hold the takePhotoButton to record the video and then it will be previewed where I preview my current still photos. Your help will really help me continuing my project. Thanks a lot!

import UIKit
import AVFoundation

@available(iOS 10.0, *)
class CameraViewController: UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate {

let photoSettings = AVCapturePhotoSettings()
    var audioPlayer = AVAudioPlayer()
    var captureSession = AVCaptureSession()
    var videoDeviceInput: AVCaptureDeviceInput!
    var previewLayer = AVCaptureVideoPreviewLayer()
    var frontCamera: Bool = false
    var captureDevice:AVCaptureDevice!
    var takePhoto = false

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        prepareCamera()
    }

    func prepareCamera() {
        captureSession.sessionPreset = AVCaptureSessionPresetPhoto

        if let availableDevices = AVCaptureDeviceDiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaTypeVideo, position: .back).devices {
            captureDevice = availableDevices.first
            beginSession()
        } 
    }

    func frontCamera(_ front: Bool){
        let devices = AVCaptureDevice.devices()

        do{
            try captureSession.removeInput(AVCaptureDeviceInput(device:captureDevice!)) 
        }catch{
            print("Error")
        }

        for device in devices!{
            if((device as AnyObject).hasMediaType(AVMediaTypeVideo)){
                if front{
                    if (device as AnyObject).position == AVCaptureDevicePosition.front {
                        captureDevice = device as? AVCaptureDevice

                        do{
                            try captureSession.addInput(AVCaptureDeviceInput(device: captureDevice!))
                        }catch{}
                        break
                    }
                }else{
                    if (device as AnyObject).position == AVCaptureDevicePosition.back {
                        captureDevice = device as? AVCaptureDevice

                        do{
                            try captureSession.addInput(AVCaptureDeviceInput(device: captureDevice!))
                        }catch{}
                        break
                    }
                }
            }
        }
    }

    func beginSession () {
        do {
            let captureDeviceInput = try AVCaptureDeviceInput(device: captureDevice)
            if let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) {
            self.previewLayer = previewLayer
            containerView.layer.addSublayer(previewLayer as? CALayer ?? CALayer())
            self.previewLayer.frame = self.view.layer.frame
            self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
            previewLayer.connection.videoOrientation = AVCaptureVideoOrientation.portrait
            captureSession.startRunning()

            let dataOutput = AVCaptureVideoDataOutput()
            dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString):NSNumber(value:kCVPixelFormatType_32BGRA)]

            dataOutput.alwaysDiscardsLateVideoFrames = true

            if captureSession.canAddOutput(dataOutput) {
                captureSession.addOutput(dataOutput)

                photoSettings.isHighResolutionPhotoEnabled = true
                photoSettings.isAutoStillImageStabilizationEnabled = true
            }

            captureSession.commitConfiguration()

            let queue = DispatchQueue(label: "com.NightOut.captureQueue")
            dataOutput.setSampleBufferDelegate(self, queue: queue) 
        }
    }
        @IBAction func takePhoto(_ sender: Any) {
            takePhoto = true

            photoSettings.isHighResolutionPhotoEnabled = true
            photoSettings.isAutoStillImageStabilizationEnabled = true
    }

    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
        if takePhoto {
            takePhoto = false
            if let image = self.getImageFromSampleBuffer(buffer: sampleBuffer) {
                let photoVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "PhotoVC") as! PhotoPreviewViewController

                photoVC.takenPhoto = image

                DispatchQueue.main.async {
                    self.present(photoVC, animated: true, completion: {
                        self.stopCaptureSession()
                    })
                }
            }  
        }
    }

    func getImageFromSampleBuffer (buffer:CMSampleBuffer) -> UIImage? {
        if let pixelBuffer = CMSampleBufferGetImageBuffer(buffer) {
            let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
            let context = CIContext()

            let imageRect = CGRect(x: 0, y: 0, width: CVPixelBufferGetWidth(pixelBuffer), height: CVPixelBufferGetHeight(pixelBuffer))

            if let image = context.createCGImage(ciImage, from: imageRect) {
                return UIImage(cgImage: image, scale: UIScreen.main.scale, orientation: .leftMirrored)
            }
    }
        return nil
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        self.captureSession.stopRunning()
    }

    func stopCaptureSession () {
        self.captureSession.stopRunning()

        if let inputs = captureSession.inputs as? [AVCaptureDeviceInput] {
            for input in inputs {
                self.captureSession.removeInput(input)
            }
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    @IBAction func DismissButtonAction(_ sender: UIButton) {

        UIView.animate(withDuration: 0.1, animations: {
            self.DismissButton.transform = CGAffineTransform.identity.scaledBy(x: 0.8, y: 0.8)
        }, completion: { (finish) in
            UIView.animate(withDuration: 0.1, animations: {
                self.DismissButton.transform = CGAffineTransform.identity
            })
        })
        performSegue(withIdentifier: "Segue", sender: nil)
    }
}

Answer 1

TouchDown event giving me crash so I use following code and it's working fine on swift5 Xcode14.3.1.

let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(longPressHandler(_:)))
        captureButton.addGestureRecognizer(longPressGesture)

 @objc func longPressHandler(_ gesture: UILongPressGestureRecognizer) {
        if gesture.state == .began {
            print("Long press began")
            videoRecordingStated()
        } else if gesture.state == .ended {
            print("Long press ended")
            videoRecordingStoped()
        }
    }

Answer 2

To identify the holding down the button and releasing it, can be done in different ways. The easiest way would be adding a target for UIControlEvents.TouchUpInside and UIControlEvents.TouchDown for capture button like below.

aButton.addTarget(self, action: Selector("holdRelease:"), forControlEvents: UIControlEvents.TouchUpInside);
aButton.addTarget(self, action: Selector("HoldDown:"), forControlEvents: UIControlEvents.TouchDown)

//target functions   
func HoldDown(sender:UIButton)
{
       // Start recording the video
}

func holdRelease(sender:UIButton)
{
       // Stop recording the video
}

There are other ways as well, like adding a long tap gesture recognizer to button or view and start/stop based on recognizer state. More info can be found here in another SO answer UIButton with hold down action and release action

Video Recording

You need to add AVCaptureMovieFileOutput to your capture session and use the method startRecordingToOutputFileURL to start the video recording.

Things to notice

• Implement AVCaptureFileOutputRecordingDelegate method to identify the start and didFinish recording
• File path should be meaningful, Which means you should give the correct file path which your app has access.

Have this code inside HoldDown() method to start recording

 let videoFileOutput = AVCaptureMovieFileOutput()
                self.captureSession?.addOutput(videoFileOutput)
 let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] as URL
 let filePath = documentsURL.appendingPathComponent("tempMovie")
 videoFileOutput.startRecording(toOutputFileURL: filePath, recordingDelegate: self)

to stop recording use vidoeFileOutput.stopRecording()

Answer 3

You need to use AVCaptureMovieFileOutput. Add AVCaptureMovieFileOutput to a capture session using addOutput(_:)

Starting a Recording

You start recording a QuickTime movie using startRecording(to:recordingDelegate:). You need to supply a file-based URL and a delegate. The URL must not identify an existing file, because the movie file output does not overwrite existing resources. You must also have permission to write to the specified location. The delegate must conform to the AVCaptureFileOutputRecordingDelegate protocol, and must implement the fileOutput(_:didFinishRecordingTo:from:error:) method.

See docs for more info.