如何在 IOS 相机中启用防抖和 HDR？答案

【问题标题】：How to enable Stabilization and HDR in IOS Camera?如何在 IOS 相机中启用防抖和 HDR？
【发布时间】：2017-08-21 06:13:47
【问题描述】：

我做了什么：-

我已尝试启用 stabilization 和 HDR，但它不起作用。我认为我的方法正确。当我尝试检查当前设备是否支持稳定时和 HDR 在这两种情况下，我在所有设备中都只得到了错误的情况。

如果下面的代码sn-p有任何错误，请指导我。

提前致谢！！

我的代码片段：-

func createAVSession() throws -> AVCaptureSession {
        AppLog.LogFunction(object: LOG_Start)

        // Start out with low quality
        let session = AVCaptureSession()
        session.sessionPreset = AVCaptureSessionPresetPhoto

        // Input from video camera
        let device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
        let currentFormat = device?.activeFormat.isVideoHDRSupported
        try device?.lockForConfiguration()
        if device?.activeFormat.isVideoHDRSupported == true {
            device?.automaticallyAdjustsVideoHDREnabled = false
            device?.isVideoHDREnabled = true
            print("device?.isVideoHDREnabled\(device?.isVideoHDREnabled)")
        }

        if (device?.isFocusModeSupported(.continuousAutoFocus))! {
            device?.focusMode = AVCaptureFocusMode.continuousAutoFocus
            print("device?.focusMode\(device?.focusMode.rawValue)")
        }
        if (device?.isSmoothAutoFocusSupported)! {
            device?.isSmoothAutoFocusEnabled = true
            print("device?.isSmoothAutoFocusEnabled\(device?.isSmoothAutoFocusEnabled)")
        }

        if (device?.isExposureModeSupported(.continuousAutoExposure))! {
            device?.exposureMode = .continuousAutoExposure
            print("device?.exposureMode\(device?.exposureMode.rawValue)")
        }
        device?.unlockForConfiguration()

        let input = try AVCaptureDeviceInput(device: device)
        do {
            try input.device.lockForConfiguration()
            input.device.activeVideoMaxFrameDuration =  CMTimeMake(1, 30)
            input.device.activeVideoMinFrameDuration =  CMTimeMake(1, 30)
            input.device.unlockForConfiguration()
        }
        catch {
            print("Failed to set FPS")
        }

        // Output
        let videoOutput = AVCaptureVideoDataOutput()

        videoOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as AnyHashable: kCVPixelFormatType_32BGRA]
        videoOutput.alwaysDiscardsLateVideoFrames = true
        videoOutput.setSampleBufferDelegate(self, queue: sessionQueue)

        let stillImageOutput: AVCaptureStillImageOutput = AVCaptureStillImageOutput()
        stillImageOutput.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]

        //stillImageOutput.isHighResolutionStillImageOutputEnabled = true

        if stillImageOutput.isStillImageStabilizationSupported {
            stillImageOutput.automaticallyEnablesStillImageStabilizationWhenAvailable = true
            print("stillImageOutput.isStillImageStabilizationActive\(stillImageOutput.isStillImageStabilizationActive)")
        }

        // Join it all together
        session.addInput(input)
        session.addOutput(videoOutput)

      if session.canAddOutput(stillImageOutput) {
            session.addOutput(stillImageOutput)
          self.stillImageOutput = stillImageOutput

      }



        if let connection = videoOutput.connection(withMediaType: AVMediaTypeVideo) {
            if connection.isVideoOrientationSupported {
                connection.videoOrientation = .portrait
            }
            if connection.isVideoStabilizationSupported {
                connection.preferredVideoStabilizationMode = .standard
                print("connection.activeVideoStabilizationMode\(connection.activeVideoStabilizationMode.rawValue)")
            }
        }


        AppLog.LogFunction(object: LOG_End)
        return session
    }

【问题讨论】：

我面临同样的问题。在 captureDevice.formats 中没有任何项目具有 format.isVideoHDRSupported == true
我也有同样的问题。你们中的任何一个都找到了解决问题的方法。只要我不使用 AVCaptureVideoDataOutputSampleBufferDelegate 等更传统的方式，我就可以稳定工作，但我必须在我的应用程序中使用委托来实现其他功能

标签： ios swift3 avfoundation avcapturesession avcam

【解决方案1】：

在稳定问题上对我有用的是在委托中对其进行测试。在我的项目中，我使用AVCaptureVideoDataOutputSampleBufferDelegate 写入我的文件，因为我在决定写入之前测试像素缓冲区中的某些内容。这是我发现的一个地方，它会说允许稳定。无论如何，这是我为稳定问题所做的。希望对您有所帮助。

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!){
    self.lockQueue.sync {
        if !self.isCapturing || self.isPaused {
            return
        }
        
        let isVideo = captureOutput is AVCaptureVideoDataOutput
        
        if isVideo && self.videoWriter == nil {
            // testing to make sure dealing with video and not audio

            let connection = captureOutput.connection(withMediaType: AVMediaTypeVideo)
          
            if (connection?.isVideoStabilizationSupported)! {
                connection?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.cinematic
            }
            
            //other work excluded as irrelevant
        }
    }
}

【讨论】：