录像没有音频？

Question

我做了一个成功的录像程序，但它没有音频？我该怎么做才能解决这个问题？我在我的info.plist中正确设置了音频权限。我正在使用AVCaptureFileOutputRecordingDelegate。

 override func viewWillAppear(_ animated: Bool) {
      let deviceDiscoverySession = AVCaptureDeviceDiscoverySession(deviceTypes: [AVCaptureDeviceType.builtInDuoCamera, AVCaptureDeviceType.builtInTelephotoCamera,AVCaptureDeviceType.builtInWideAngleCamera], mediaType: AVMediaTypeVideo, position: AVCaptureDevicePosition.back)

    for device in (deviceDiscoverySession?.devices)!{
        if(device.position == AVCaptureDevicePosition.back){

            do{
                let input = try AVCaptureDeviceInput(device: device )

                if captureSession.canAddInput(input){

                    captureSession.addInput(input)

                }

               // sessionOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString) : NSNumber(value: kCVPixelFormatType_420YpCbCr8BiPlanarFullRange as UInt32)]

                sessionOutput.alwaysDiscardsLateVideoFrames = true

                if(captureSession.canAddOutput(sessionOutput) == true){
                    captureSession.addOutput(sessionOutput)

                    let previewLayer: AVCaptureVideoPreviewLayer = {
                        let preview =  AVCaptureVideoPreviewLayer(session: self.captureSession)
                        preview?.bounds = CGRect(x: 0, y: 0, width: self.view.bounds.width, height: self.view.bounds.height)
                        preview?.position = CGPoint(x: self.view.bounds.midX, y: self.view.bounds.midY)
                        preview?.videoGravity = AVLayerVideoGravityResize
                        return preview!
                    }()

                    view.layer.insertSublayer(previewLayer, at: 0)

                    output = AVCaptureMovieFileOutput()
                    let maxDuration = CMTimeMakeWithSeconds(180, 30)
                    output.maxRecordedDuration = maxDuration
                    captureSession.addOutput(output)



                }

                captureSession.commitConfiguration()

            }

            catch{
                print("Error")
            }


        }

    }

我已经尝试过here的解决方案，但是它所做的只是把我已经在用相机工作的东西搞砸了。如有任何指导，将不胜感激！

Answer 1

简单的步骤，以实现您想要的：

1. 获取视频捕获设备(AVMediaTypeVideo)
2. 获取音频捕获设备(AVMediaTypeAudio)
3. 创建视频输入(带有视频设备的AVCaptureDeviceInput)
4. 创建音频输入(带有音频设备的AVCaptureDeviceInput)
5. 通过AVCaptureSession()配置捕获会话(BeginConfiguration)
6. 通过addInput()添加捕获会话的输入
7. 通过commitConfiguration()提交配置

Answer 2

添加音频输入后，如果您仍然面临一些录音持续时间后丢失的音频问题。用这个代码。对我起作用了。

videoOutput?.movieFragmentInterval = .invalid