我试图在视图控制器加载个人资料照片后立即获得相机预览，以加载实时视频。 但是，视频一开始没有显示。这是真正的iPhone，而不是

Question

感谢您的任何建议。

旋转相机代码

 @objc func showLivePreview(view: UIView) {
            var myPreviewLayer = AVCaptureVideoPreviewLayer()
            let captureSession = AVCaptureSession()
            var backCamera: AVCaptureDevice?
            var frontCamera: AVCaptureDevice?
            var currentCamera: AVCaptureDevice?
    
            var videoOutput = AVCaptureVideoDataOutput()
          
          
           // Step 1: Set up the preview layer
            myPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
           myPreviewLayer.videoGravity = .resizeAspectFill
           myPreviewLayer.connection?.videoOrientation = .portrait
            captureSession.sessionPreset = AVCaptureSession.Preset.photo
 let session = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: .video, position: .front)
        
        let devices = session.devices
        currentCamera = devices.first
           
            do{
    
                   let captureDeviceInput = try AVCaptureDeviceInput(device: currentCamera!)
                   print(captureDeviceInput)
                   captureSession.addInput(captureDeviceInput)
                   
                   let videoOutput = AVCaptureMovieFileOutput()
                    
                   captureSession.addOutput(videoOutput)
                
    
               }catch{
    
                   return
               }
                
           view.layer.addSublayer(myPreviewLayer)
           
           // Make layer rounded
           view.layer.cornerRadius = view.bounds.width / 2
           view.layer.masksToBounds = true
           print("finished with layer. start camera")
           
            
            myPreviewLayer.session = captureSession
          
           let photoOutput = AVCapturePhotoOutput()
            if captureSession.canAddOutput(photoOutput ) {
                captureSession.addOutput(photoOutput )
           }
           
           // Position layer in UI
           myPreviewLayer.frame = view.frame//was bounds
           
           // Start the session in background thread as per Thread Performance Checker
           DispatchQueue.global().async {
               captureSession.startRunning() 
       }

相机是从使用情节板的Objective-C编写的VC中调用的。我尚未尝试定位相机，因此视图自我。视图只是故事板的主视图。

对象c

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [[Utilities shared] showLivePreviewWithView:self.view];
}