更换相机后相机帧数下降 iOS

Question

我的方法 didOutputSampleBuffer 被成功调用，直到我使用此功能切换相机：

func switchCameras() {

    captureSession.beginConfiguration()
    captureSession.sessionPreset = AVCaptureSessionPresetMedium
    var error : NSError? = nil
    for input in captureSession.inputs {
        captureSession.removeInput(input as! AVCaptureInput)
    }
    if currentCamera == "back" {
        currentCamera = "front"

        if captureSession.canAddInput(AVCaptureDeviceInput(device: frontCamera, error: &error)) {
            captureSession.addInput(AVCaptureDeviceInput(device: frontCamera, error: &error))
        } else {
            print(error)
        }
    } else {
        currentCamera = "back"
        if captureSession.canAddInput(AVCaptureDeviceInput(device: backCamera, error: &error)) {
            captureSession.addInput(AVCaptureDeviceInput(device: backCamera, error: &error))
        } else {
        }
    }
    print("chagned")
    captureSession.commitConfiguration()
}

切换后，此方法有时会掉帧，无法拍照。大约 5 秒后，帧返回。

func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    connection.videoOrientation = AVCaptureVideoOrientation.Portrait

    if capture == true {
        self.capture = false
        var newBuffer = sampleBuffer
            self.capturePicture(newBuffer)


    }
}

如果您需要更多代码，请告诉我。

Answer 1

我通过将输出队列更改为 DISPATCH_QUEUE_SERIAL 解决了这个问题。

let output = AVCaptureVideoDataOutput()
output.videoSettings = [kCVPixelBufferPixelFormatTypeKey as NSString:kCVPixelFormatType_32BGRA]
let queue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL)
output.setSampleBufferDelegate(self, queue: dispatch_get_main_queue())

更换相机后相机帧数下降 iOS

Camera frames dropped after changing camera iOS

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