swift - func captureOutput 永远不会被调用

Question

添加喜欢为我实时记录的每一帧添加过滤器并将过滤后的图像显示在 UIImageView 中，如果有人可以帮助它会很好。但从未调用 captureoutput，这是我的代码。

class Measurement: UIViewController , AVCaptureVideoDataOutputSampleBufferDelegate {
    @IBOutlet weak var cameraPreview: UIView!
    @IBOutlet weak var imageView: UIImageView!

    override func viewDidLoad() {
            super.viewDidLoad()

            setupCameraSession()
                toggleTorch(on: true)

        }

        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)

            view.layer.addSublayer(previewLayer)

            cameraSession.startRunning()
        }

        lazy var cameraSession: AVCaptureSession = {
            let s = AVCaptureSession()

            s.sessionPreset = AVCaptureSession.Preset.low
            return s
        }()

        lazy var previewLayer: AVCaptureVideoPreviewLayer = {
            let preview =  AVCaptureVideoPreviewLayer(session: self.cameraSession)
            preview.position = CGPoint(x:182,y: 485)
            preview.videoGravity = AVLayerVideoGravity.resizeAspectFill
            preview.connection?.videoOrientation = AVCaptureVideoOrientation.portrait

            preview.bounds = imageView.bounds
            //preview.position = CGPoint(x:self.view.bounds.midX,y: self.view.bounds.midY)
            imageView.layer.addSublayer(preview)

            return preview
        }()

        func toggleTorch(on: Bool) {
            guard let device = AVCaptureDevice.default(for: .video) else { return }

            if device.hasTorch {
                do {
                    try device.lockForConfiguration()

                    if on == true {
                        device.torchMode = .on
                    } else {
                        device.torchMode = .off
                    }

                    device.unlockForConfiguration()
                } catch {
                    print("Torch could not be used")
                }
            } else {
                print("Torch is not available")
            }
        }
        func setupCameraSession() {
            let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

            do {
                let deviceInput = try AVCaptureDeviceInput(device: captureDevice!)

                cameraSession.beginConfiguration()

                if (cameraSession.canAddInput(deviceInput) == true) {
                    cameraSession.addInput(deviceInput)
                    print("Processing Data.")
                }

                let dataOutput = AVCaptureVideoDataOutput()
                dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString) : NSNumber(value: kCVPixelFormatType_32BGRA as UInt32)] as [String : AnyObject]
                dataOutput.alwaysDiscardsLateVideoFrames = true

                 print("Processing Data.")
                if (cameraSession.canAddOutput(dataOutput) == true) {
                    cameraSession.addOutput(dataOutput)
                    print("Processing Data.")
                }

                cameraSession.commitConfiguration()

                let queue = DispatchQueue(label: "com.invasivecode.videoQueue")
                dataOutput.setSampleBufferDelegate(self, queue: queue)

            }
            catch let error as NSError {
                print("\(error), \(error.localizedDescription)")
            }
        }

    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {


        print("Processing Data.")


        guard let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return  }
        //let chromaKeyFilter = colorCubeFilterForChromaKey(hueAngle: 120)
        let ciImage = CIImage(cvPixelBuffer: imageBuffer)

        let context = CIContext()
        guard let cgImage = context.createCGImage(ciImage, from: ciImage.extent) else { return  }

        let image = UIImage(cgImage: cgImage)
        if let chromaKeyFilter = CIFilter(name: "CISepiaTone") {
            let beginImage = CIImage(image: image)
            chromaKeyFilter.setValue(beginImage, forKey: kCIInputImageKey)
            chromaKeyFilter.setValue(0.5, forKey: kCIInputIntensityKey)

            if let output = chromaKeyFilter.outputImage {
                if let cgimg = context.createCGImage(output, from: output.extent) {
                    let processedImage = UIImage(cgImage: cgimg)
                    // do something interesting with the processed image
                    imageView.image = processedImage
                }
            }
        }
    }








func captureOutput(_ captureOutput: AVCaptureOutput, didDrop sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        // Here you can count how many frames are dopped
    }
func startCapture() {
    print("\(self.classForCoder)/" + #function)
    if cameraSession.isRunning {

        print("already running")
        return
    }
    cameraSession.startRunning()
    toggleTorch(on: true)


}

Answer 1

你需要设置委托(delegate)

dataOutput.sampleBufferDelegate = self