Question

我正在尝试构建一个相机应用，我试图在我的主视图控制器中的viewDidLoad（）中设置我的捕获会话。出于某种原因，每当我在手机上运行应用程序时，AVCaptureSession方法canAddOutput都会被评估为false：

var captureSession: AVCaptureSession!
var photoOutput: AVCapturePhotoOutput!
var previewLayer : AVCaptureVideoPreviewLayer!

//MARK: Outlets
@IBOutlet weak var previewView: UIView!

override func viewDidLoad() {
    super.viewDidLoad()
    captureSession = AVCaptureSession()
    captureSession.sessionPreset = AVCaptureSessionPresetPhoto

    //Ask permission to camera
    let device = AVCaptureDevice.defaultDevice(withDeviceType: .builtInWideAngleCamera, mediaType: AVMediaTypeVideo, position: .back)
    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo, completionHandler: { (granted: Bool) in
        if granted {
            print("granted")
            //Set up session
            if let input = try? AVCaptureDeviceInput(device: device) {
                print("Input = device")
                if (self.captureSession.canAddInput(input)) {
                    self.captureSession.addInput(input)
                    print("Input added to capture session")
                    if (self.captureSession.canAddOutput(self.photoOutput)) {
                        print("Output added to capture session")
                        self.captureSession.addOutput(self.photoOutput)
                        self.previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
                        self.previewLayer.frame = self.previewView.bounds
                        self.previewView.layer.addSublayer(self.previewLayer!)
                        self.captureSession.startRunning()
                        print("Session is running")
                    }
                }
            }

        }
        else {
            print("Goodbye")
        }
    })

}

不幸的是，我只能打印它直到＆＃34;输入添加到捕获会话＆＃34;。任何建议都会有所帮助 - 谢谢！

Answer 1

您必须删除会话中添加的先前输出。您可以为此使用for循环。

for outputs in captureSession.outputs{ captureSession.removeOutput(outputs) }

然后尝试添加新的输出

为什么AVCaptureSession方法canAddOutput返回false？

1 个答案: