Camera frames dropped after changing iOS camera

Question

My didOutputSampleBuffer method is called successfully until I switch cameras using this function:

 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() } 

After switching to this method, frames are sometimes discarded, so I can’t take a picture. After about 5 seconds, the frames return.

 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) } } 

IF you need more code let me know.

Answer 1

I solved this by changing the output queue to DISPATCH_QUEUE_SERIAL .

 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())