返回上级目录：ios AVFoundation（音视频解码，直播，相机）
官方文档
苹果官方文档：Setting Up a Capture Session
示例代码：
import UIKit
import AVFoundation
class PreviewView: UIView {
override class var layerClass: AnyClass {
return AVCaptureVideoPreviewLayer.self
}
var videoPreviewLayer: AVCaptureVideoPreviewLayer {
return layer as! AVCaptureVideoPreviewLayer
}
}
class ViewController: UIViewController {
var captureSession: AVCaptureSession?
let previewView = PreviewView()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
switch AVCaptureDevice.authorizationStatus(for: .video) {
case .authorized: // The user has previously granted access to the camera.
self.setupCaptureSession()
case .notDetermined: // The user has not yet been asked for camera access.
AVCaptureDevice.requestAccess(for: .video) {
granted in
if granted {
self.setupCaptureSession()
}
}
case .denied: // The user has previously denied access.
return
case .restricted: // The user can't grant access due to restrictions.
return
}
}
func setupCaptureSession() {
captureSession = AVCaptureSession()
guard let captureSession = captureSession else {
return
}
captureSession.beginConfiguration()
let videoDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back)
guard let videoDeviceInput = try? AVCaptureDeviceInput(device: videoDevice!),captureSession.canAddInput(videoDeviceInput) else {
return
}
captureSession.addInput(videoDeviceInput)
let photoOutput = AVCapturePhotoOutput()
guard captureSession.canAddOutput(photoOutput) else {
return }
captureSession.sessionPreset = .photo
captureSession.addOutput(photoOutput)
captureSession.commitConfiguration()
previewView.frame = view.bounds
previewView.videoPreviewLayer.session = captureSession
view.addSubview(previewView)
captureSession.startRunning()
}
}
AVCaptureDevice.default方法三个参数的解释
参数的枚举选择不对，可能会导致初始化失败。如设备类型你选了.builtInDualWideCamera.但是6s的手机没有两个广角相机，那么在6s手机上运行是就会返回nil
设备类型 AVCaptureDevice.DeviceType
