问在IOS应用程序中构建摄像头时出错

EN

if previewLayer = AVCaptureVideoPreviewLayer(session: captureSession){

self.previewLayer = previewLayer
self.view.layer.addSublayer(self.previewLayer)
self.previewLayer.frame = self.view.layer.frame
captureSession.startRunning()

let dataOutput = AVCaptureVideoDataOutput()
dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString):NSNumber(value:kCVPixelFormatType_32BGRA)] as [String : Any]

dataOutput.alwaysDiscardsLateVideoFrames = true

if captureSession.canAddOutput(dataOutput) {
    captureSession.addOutput(dataOutput)
}

captureSession.commitConfiguration()

let queue = DispatchQueue(label: "com.brianadvent.captureQueue")
    dataOutput.setSampleBufferDelegate(self, queue: queue)
}