Capture Live Photo

CameraService.swift

protocol CameraService {
  var delegate: CameraServiceDelegate? { get set }

  func start() async
  func capture()
}

@MainActor
protocol CameraServiceDelegate: AnyObject {
  func didRecord(livePhoto: URL)
  func didReceive(error: Error)
}

final class DefaultCameraService: NSObject, CameraService {
  weak var delegate: CameraServiceDelegate?
  private var captureSession = AVCaptureSession()
  private let photoOutput = AVCapturePhotoOutput()

  func start() async {
    guard !captureSession.isRunning else { return }
    captureSession.startRunning()
    captureSession.beginConfiguration()
    captureSession.sessionPreset = .photo
    guard let frontCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front),
          let frontCameraDeviceInput = try? AVCaptureDeviceInput(device: frontCameraDevice),
          let microphoneDevice = AVCaptureDevice.default(for: .audio),
          let microphoneDeviceInput = try? AVCaptureDeviceInput(device: microphoneDevice),
          captureSession.canAddInput(frontCameraDeviceInput),
          captureSession.canAddInput(microphoneDeviceInput) else {
      fatalError()
    }
    captureSession.addInput(frontCameraDeviceInput)
    captureSession.addInput(microphoneDeviceInput)
    guard captureSession.canAddOutput(photoOutput) else {
      fatalError()
    }
    captureSession.addOutput(photoOutput)
    photoOutput.isAutoDeferredPhotoDeliveryEnabled = photoOutput.isAutoDeferredPhotoDeliverySupported
    photoOutput.isFastCapturePrioritizationEnabled = photoOutput.isFastCapturePrioritizationSupported
    photoOutput.isResponsiveCaptureEnabled = photoOutput.isResponsiveCaptureSupported
    photoOutput.isZeroShutterLagEnabled = photoOutput.isZeroShutterLagSupported
    photoOutput.isAppleProRAWEnabled = photoOutput.isAppleProRAWSupported
    photoOutput.isContentAwareDistortionCorrectionEnabled = photoOutput.isContentAwareDistortionCorrectionSupported
    photoOutput.isLivePhotoCaptureEnabled = photoOutput.isLivePhotoCaptureSupported
    photoOutput.isLivePhotoAutoTrimmingEnabled = true
    photoOutput.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliverySupported
    photoOutput.isPortraitEffectsMatteDeliveryEnabled = photoOutput.isPortraitEffectsMatteDeliverySupported
    photoOutput.isVirtualDeviceConstituentPhotoDeliveryEnabled = photoOutput.isVirtualDeviceConstituentPhotoDeliverySupported
    captureSession.commitConfiguration()
  }

  func capture() {
    let photoSettings = AVCapturePhotoSettings()
    photoSettings.flashMode = .auto
    photoSettings.isAutoRedEyeReductionEnabled = photoOutput.isAutoRedEyeReductionSupported
    photoSettings.maxPhotoDimensions = photoOutput.maxPhotoDimensions
    photoSettings.photoQualityPrioritization = photoOutput.maxPhotoQualityPrioritization
    photoSettings.isCameraCalibrationDataDeliveryEnabled = photoOutput.isCameraCalibrationDataDeliverySupported
    photoSettings.isAutoContentAwareDistortionCorrectionEnabled = photoOutput.isContentAwareDistortionCorrectionSupported
    photoSettings.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliverySupported
    photoSettings.isPortraitEffectsMatteDeliveryEnabled = photoOutput.isPortraitEffectsMatteDeliverySupported
    photoSettings.livePhotoMovieFileURL = URL.temporaryDirectory.appendingPathComponent(UUID().uuidString, conformingTo: .quickTimeMovie)
    photoSettings.livePhotoVideoCodecType = .hevc
    photoOutput.capturePhoto(with: photoSettings, delegate: self)
  }

  private func stop() {
    captureSession.stopRunning()
    captureSession = AVCaptureSession()
  }
}

extension DefaultCameraService: AVCapturePhotoCaptureDelegate {

  func photoOutput(_ output: AVCapturePhotoOutput, didFinishCapturingDeferredPhotoProxy deferredPhotoProxy: AVCaptureDeferredPhotoProxy?, error: Error?) {}
  
  func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {}

  func photoOutput(
    _ output: AVCapturePhotoOutput,
    didFinishProcessingLivePhotoToMovieFileAt outputFileURL: URL,
    duration: CMTime,
    photoDisplayTime: CMTime,
    resolvedSettings: AVCaptureResolvedPhotoSettings,
    error: Error?
  ) {
    MainActor.assumeIsolated {
      if let error {
        delegate?.didReceive(error: error)
      } else {
        delegate?.didRecord(livePhoto: outputFileURL)
      }
    }
    stop()
  }
}