How to switch camera using AVFoundation - ios

Question

I have implemented the preview camera using AVFoundation, its working fine. But I have a hard time to switch the camera back and front. I have added a switch button at the bottom bar. By default, its the back camera, I want to switch it to front. How can I do that?
class FifteenSecsViewController: UIViewController, AVCaptureFileOutputRecordingDelegate {
#IBOutlet weak var camPreview: UIView!
let captureSession = AVCaptureSession()
let movieOutput = AVCaptureMovieFileOutput()
var previewLayer: AVCaptureVideoPreviewLayer!
var activeInput: AVCaptureDeviceInput!
var outputURL: URL!
override func viewDidLoad() {
super.viewDidLoad()
if setupSession() {
setupPreview()
startSession()
}
self.switchCameraButton.addTarget(self, action: #selector(switchButtonTapped), for: .touchUpInside)
}
func setupSession() -> Bool {
captureSession.sessionPreset = AVCaptureSession.Preset.high
// Setup Camera
let camera: AVCaptureDevice?
camera = AVCaptureDevice.default(for: .video)
do {
let input = try AVCaptureDeviceInput(device: camera!)
if captureSession.canAddInput(input) {
captureSession.addInput(input)
activeInput = input
}
} catch {
print("Error setting device video input: \(error)")
return false
}
// Setup Microphone
let microphone = AVCaptureDevice.default(for: .audio)
do {
let micInput = try AVCaptureDeviceInput(device: microphone!)
if captureSession.canAddInput(micInput) {
captureSession.addInput(micInput)
}
} catch {
print("Error setting device audio input: \(error)")
return false
}
// Movie output
let seconds : Int64 = 3
let maxDuration = CMTime(seconds: Double(seconds),
preferredTimescale: 1)
movieOutput.maxRecordedDuration = maxDuration
if captureSession.canAddOutput(movieOutput) {
captureSession.addOutput(movieOutput)
}
return true
}
func setupPreview() {
// Configure previewLayer
previewLayer = AVCaptureVideoPreviewLayer(session:
captureSession)
previewLayer.frame = camPreview.bounds
previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
camPreview.layer.addSublayer(previewLayer)
}
//MARK:- Camera Session
func startSession() {
if !captureSession.isRunning {
videoQueue().async {
self.captureSession.startRunning()
}
}
}
#objc func switchButtonTapped(){
// what to write here??
}
}
Function switchButtonTapped is an actionTarget of UIButton. If I add this code in this button:
#objc func switchButtonTapped(){
if setupSession() {
setupPreview()
startSession()
}
}
Camerapreview screen shows a white screen and got stuck.

Answer 1

Try this code:
func switchCamera() {
session?.beginConfiguration()
let currentInput = session?.inputs.first as? AVCaptureDeviceInput
session?.removeInput(currentInput!)
let newCameraDevice = currentInput?.device.position == .back ? getCamera(with: .front) : getCamera(with: .back)
let newVideoInput = try? AVCaptureDeviceInput(device: newCameraDevice!)
session?.addInput(newVideoInput!)
session?.commitConfiguration()
}
func getCamera(with position: AVCaptureDevice.Position) -> AVCaptureDevice? {
guard let devices = AVCaptureDevice.devices(for: AVMediaType.video) as? [AVCaptureDevice] else {
return nil
}
return devices.filter {
$0.position == position
}.first
}

Answer 2

To begin create a device input for the front camera:
let frontDevice: AVCaptureDevice? = {
for device in AVCaptureDevice.devices(for: AVMediaType.video) {
if device.position == .front {
return device
}
}
return nil
}()
lazy var frontDeviceInput: AVCaptureDeviceInput? = {
if let _frontDevice = self.frontDevice {
return try? AVCaptureDeviceInput(device: _frontDevice)
}
return nil
}()
Then in your switchButtonTapped, if there is a front camera you can do the switch between the front and the ones:
func switchButtonTapped() {
if let _frontDeviceInput = frontDeviceInput {
captureSession.beginConfiguration()
if let _currentInput = captureSession.inputs.first as? AVCaptureDeviceInput {
captureSession.removeInput(_currentInput)
let newDeviceInput = (_currentInput.device.position == .front) ? activeInput : _frontDeviceInput
captureSession.addInput(newDeviceInput!)
}
captureSession.commitConfiguration()
}
}
If you need more details, don't hesitate.