如何获取AVCaptureVideoPreviewLayer的UIImage而不是AVCapturePhotoOutput捕获

如何获取AVCaptureVideoPreviewLayer的UIImage而不是AVCapturePhotoOutput捕获

基本上，应该使用AVCaptureVideoDataOutputSampleBufferDelegate而不是使用AVCaptureVideoPreviewLayer来捕获帧。这是示例：

import Foundationimport UIKitimport AVFoundationprotocol CaptureManagerDelegate: class {    func processCapturedImage(image: UIImage)}class CaptureManager: NSObject {    internal static let shared = CaptureManager()    weak var delegate: CaptureManagerDelegate?    var session: AVCaptureSession?    override init() {        super.init()        session = AVCaptureSession()        //setup input        let device =  AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)        let input = try! AVCaptureDeviceInput(device: device)        session?.addInput(input)        //setup output        let output = AVCaptureVideoDataOutput()        output.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable: kCVPixelFormatType_32BGRA]        output.setSampleBufferDelegate(self, queue: DispatchQueue.main)        session?.addOutput(output)    }    func statSession() {        session?.startRunning()    }    func stopSession() {        session?.stopRunning()    }    func getImageFromSampleBuffer(sampleBuffer: CMSampleBuffer) ->UIImage? {        guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return nil        }        CVPixelBufferLockbaseAddress(pixelBuffer, .readOnly)        let baseAddress = CVPixelBufferGetbaseAddress(pixelBuffer)        let width = CVPixelBufferGetWidth(pixelBuffer)        let height = CVPixelBufferGetHeight(pixelBuffer)        let bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer)        let colorSpace = CGColorSpaceCreateDeviceRGB()        let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedFirst.rawValue | CGBitmapInfo.byteOrder32Little.rawValue)        guard let context = CGContext(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo.rawValue) else { return nil        }        guard let cgImage = context.makeImage() else { return nil        }        let image = UIImage(cgImage: cgImage, scale: 1, orientation:.right)        CVPixelBufferUnlockbaseAddress(pixelBuffer, .readOnly)        return image    }}extension CaptureManager: AVCaptureVideoDataOutputSampleBufferDelegate {    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {        guard let outputImage = getImageFromSampleBuffer(sampleBuffer: sampleBuffer) else { return        }        delegate?.processCapturedImage(image: outputImage)    }}

更新：
要处理图像，您应该在所需的任何其他类中实现CaptureManagerDelegate协议的processCapturedImage方法，例如：

import UIKitclass ViewController: UIViewController {    @IBOutlet weak var imageView: UIImageView!    override func viewDidLoad() {        super.viewDidLoad()        CaptureManager.shared.statSession()        CaptureManager.shared.delegate = self    }}extension ViewController: CaptureManagerDelegate {    func processCapturedImage(image: UIImage) {        self.imageView.image = image    }}