Question

ARSCNView会自动将设备摄像头的实时视频输入渲染为场景背景。但我尝试手动将场景背景内容设置为其中一个iPhone X相机。我可以成功地将sceneView.scene.background.contents设置为颜色，图像等，但不能设置为前置或后置摄像头。我已经尝试将sceneView.scene.background.contents设置为AVCaptureDevice，AVCaptureDeviceInput和AVCaptureVideoPreviewLayer。我还在另一个视图中尝试了一个独立的AVCaptureVideoPreviewLayer。这些都不会同时导致摄像机视频和人脸跟踪。

我觉得它可能与ARFaceTrackingConfiguration（）有关，自动使用前置摄像头，无法同时显示单独的摄像头视频？我认为iOS 11.2中存在某种错误，但我在11.3中没有成功。根据我的方法，我得到以下一个：

视频和面部跟踪冻结
脸部追踪有效但视频冻结
视频有效但面部跟踪冻结
冻结之前的几个视频帧和/或面罩帧

Swift4 / iOS11 / iPhone X

直接设置scene.background.contents：

@IBOutlet weak var sceneView: ARSCNView!

override func viewDidAppear(_ animated: Bool) {
  super.viewDidAppear(animated)
  sceneView.delegate = self
  sceneView.session.run(ARFaceTrackingConfiguration())

  // wait for scene and camera to activate
  DispatchQueue.main.asyncAfter(deadline: .now() + 4.0) {
    let captureDevice = AVCaptureDevice.default(. builtInWideAngleCamera, for: .video, position: .front)!
    self.sceneView.scene.background.contents = captureDevice
  }
}

使用单独的视频图层：

@IBOutlet weak var sceneView: ARSCNView!
var captureSession = AVCaptureSession()
var inp: AVCaptureDeviceInput!
var videoPreviewLayer: AVCaptureVideoPreviewLayer!

override func viewDidAppear(_ animated: Bool) {
  super.viewDidAppear(animated)
  sceneView.delegate = self
  sceneView.scene.background.contents = UIColor.yellow
  sceneView.session.run(ARFaceTrackingConfiguration())

  if let cam = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front) {
    do { inp = try AVCaptureDeviceInput(device: cam) }
    catch { fatalError("Failed to get device input") }
  } else { fatalError("Failed to get camera device") }

  captureSession.addInput(inp)
  videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
  videoPreviewLayer?.frame = view.bounds
  videoPreviewLayer?.videoGravity = .resizeAspectFill

  DispatchQueue.main.asyncAfter(deadline: .now() + 4.0) {
    self.captureSession.startRunning()
    self.view.layer.addSublayer(self.videoPreviewLayer!)
  }
}

Answer 1

似乎一次只能使用一台摄像机？

https://developer.apple.com/library/content/documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/04_MediaCapture.html#//apple_ref/doc/uid/TP40010188-CH5-SW25

注意：媒体捕获不支持同时捕获iOS设备上的前置摄像头和后置摄像头。

将ARSCNView场景背景内容设置为iPhone X相机

1 个答案: