iOS摄像头视频处理的基础demo，打不开摄像头

Question

背景
1. Xcode 9.2
1. Swift 4
1. iOS 11.4

摄像头的访问基础设定都做好了的！

在网上查很多资料借鉴了网上大神的编程写了一个AVFoundation的摄像头视频处理。
想要做的事，就像OpenCV使用摄像头识别东西一样，编程一个还没有开始任何图像处理，但读取了每一帧摄像的基础demo，以便以后使用。现在把程序写出来了，但是摄像头没有打开，也没有错误，不知道该怎么办好，求助大神帮忙看看.

class ViewController: UIViewController,AVCaptureDelegate {

    @IBOutlet weak var imageView: UIImageView!
    var avCapture = AVCapture()

    override func viewDidLoad() {

        super.viewDidLoad()
        avCapture.delegate = self
    }

    func capture(image: UIImage) {
        imageView.image = image

    }
}

protocol AVCaptureDelegate {
    func capture(image: UIImage)
}

class AVCapture:NSObject, AVCaptureVideoDataOutputSampleBufferDelegate {

    var captureSession: AVCaptureSession!
    var delegate: AVCaptureDelegate?


    var counter = 0
    let DISMISS_COUNT = 1


    override init(){
        super.init()

        captureSession = AVCaptureSession()
        captureSession.sessionPreset = AVCaptureSession.Preset.hd1920x1080


        let videoDevice = AVCaptureDevice.default(for: AVMediaType.video)
        videoDevice?.activeVideoMinFrameDuration = CMTimeMake(1, 30)// 1/30秒 (１秒間30frame)


        let videoInput = try! AVCaptureDeviceInput.init(device: videoDevice!)
        captureSession.addInput(videoInput)


        let videoDataOutput = AVCaptureVideoDataOutput()
        videoDataOutput.setSampleBufferDelegate(self, queue: DispatchQueue.main)
        videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : Int(kCVPixelFormatType_32BGRA)]
        videoDataOutput.alwaysDiscardsLateVideoFrames = true

        captureSession.addOutput(videoDataOutput)

        DispatchQueue.global(qos: .userInitiated).async {
            self.captureSession.startRunning()
        }

    }
    // SampleBuffer  UIImage作成
    func imageFromSampleBuffer(sampleBuffer :CMSampleBuffer) -> UIImage {

        let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!

        CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
        // 画像情報
        let base = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0)!
        let bytesPerRow = UInt(CVPixelBufferGetBytesPerRow(imageBuffer))
        let width = CVPixelBufferGetWidth(imageBuffer)
        let height = CVPixelBufferGetHeight(imageBuffer)

        CVPixelBufferUnlockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))

        let colorSpace = CGColorSpaceCreateDeviceRGB()
        let bitsPerCompornent = 8
        let bitmapInfo = CGBitmapInfo(rawValue: (CGBitmapInfo.byteOrder32Little.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue) as UInt32)
        let newContext = CGContext(data: base, width: width, height: height, bitsPerComponent: Int(bitsPerCompornent), bytesPerRow: Int(bytesPerRow), space: colorSpace, bitmapInfo: bitmapInfo.rawValue)! as CGContext
        // 画像作成
        let imageRef = newContext.makeImage()!
        let image = UIImage(cgImage: imageRef, scale: 1.0, orientation: UIImageOrientation.right)
        return image
    }


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

        if (counter % DISMISS_COUNT) == 0 {

            let image = imageFromSampleBuffer(sampleBuffer: sampleBuffer)
            delegate?.capture(image: image)

            if let camData = CMGetAttachment(sampleBuffer, kCMSampleBufferAttachmentKey_CameraIntrinsicMatrix, nil) as? Data {

                let matrix: matrix_float3x3 = camData.withUnsafeBytes { $0.pointee }
                print(matrix)
            }
        }
        counter += 1
    }

}

Answer 1

需要在info 里面设置，启动相机功能。