iOS 除非打开 Quicktime，否则 AVCaptureDevice.devices() 不会列出设备

Question

我正在尝试在 Swift 操场上使用 AVCaptureDevice.devices() 列出连接到我的机器的设备。

import Cocoa
import Foundation
import AVFoundation
import CoreMediaIO

var prop = CMIOObjectPropertyAddress(
    mSelector: CMIOObjectPropertySelector(kCMIOHardwarePropertyAllowScreenCaptureDevices),
    mScope: CMIOObjectPropertyScope(kCMIOObjectPropertyScopeGlobal),
    mElement: CMIOObjectPropertyElement(kCMIOObjectPropertyElementMaster))

var allow : UInt32 = 1
let dataSize : UInt32 = 4
let zero : UInt32 = 0
CMIOObjectSetPropertyData(CMIOObjectID(kCMIOObjectSystemObject), &prop, zero, nil, dataSize, &allow)


var session = AVCaptureSession()
session.sessionPreset = AVCaptureSession.Preset.low

let devices = AVCaptureDevice.devices()
for device in devices {
    let deviceID = device.uniqueID
    let deviceName = device.localizedName
    print("\(deviceID): \(deviceName)")
}

即使我的 iPhone 已连接到我的计算机

，这也会给我以下结果

04-52-c7-c1-65-c4:input: Bose Tito
AppleHDAEngineInput:1B,0,1,0:1: Built-in Microphone
CC26311ECFEG1HNBA: FaceTime HD Camera

现在我注意到，如果我启动 Quicktime Player，select 新电影录制和 select 将我的设备作为相机源，然后我的设备会被列出

04-52-c7-c1-65-c4:input: Bose Tito
AppleHDAEngineInput:1B,0,1,0:1: Built-in Microphone
CC26311ECFEG1HNBA: FaceTime HD Camera
12345b7406eeb053e2d5cded2527315d6110a16e: tito

有什么办法可以防止这种情况发生吗？

Answer 1

您需要稍等一下设备才会出现。

注册 AVCaptureDeviceWasConnectedNotification 可在可用时收到通知。

Answer 2

您如何检查 iOS 设备是否已准备好使用？我有同样的问题和我正在进行的项目。

目前，如果我打开 quicktime，它就可以工作，（我也对设备 ID 进行了硬编码，但需要删除它）

 override func viewDidLoad() {

    super.viewDidLoad()
    enableDalDevices()

    camera.layer = CALayer()
    let session:AVCaptureSession = AVCaptureSession()
    session.sessionPreset = AVCaptureSession.Preset.high
    let listdevices:Array = (AVCaptureDevice.devices())


   // Grabs iOS device on system change value in array [X] depending on devices connected on your own Mac
    let device:AVCaptureDevice = listdevices[6]

 do {
   try session.addInput(AVCaptureDeviceInput(device: device))

    //Preview
    let previewLayer:AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: session)
    let myView:NSView = self.view
    previewLayer.frame = myView.bounds
    previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
    previewLayer.connection?.videoOrientation = AVCaptureVideoOrientation.landscapeRight

    self.camera.layer?.addSublayer(previewLayer)
    session.startRunning()

            print(listdevices)

    } catch {

            }


}

Answer 3

使用@Valerian 的回答来帮助回答@adamprocter，这就是我最终解决它的方法。

override func viewDidLoad() {

    super.viewDidLoad()
    enableDalDevices()

    camera.layer = CALayer()
    let session:AVCaptureSession = AVCaptureSession()
    session.sessionPreset = AVCaptureSession.Preset.high

    let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.externalUnknown], mediaType: .muxed, position: .unspecified)
    //You get the devices here and their IDs and do whatever you want
    showDevices(devices: discoverySession.devices)

    //Register for a notification just like @Valerian said earlier
    NotificationCenter.default.addObserver(self, selector: #selector(newDevice), name: NSNotification.Name.AVCaptureDeviceWasConnected, object: nil)

}

@objc func newDevice() {
    let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.externalUnknown], mediaType: .muxed, position: .unspecified)
    showDevices(devices: discoverySession.devices)
}

iOS 除非打开 Quicktime，否则 AVCaptureDevice.devices() 不会列出设备

iOS Device not listed by AVCaptureDevice.devices() unless Quicktime is opened

quicktime

avfoundation

ios

swift