A script illustrating the recommended NatCam-OpenCV workflow.

NatCam+OpenCV.cs

byte[] pixelBuffer;
Mat previewMatrix;

void Start () {
    // Start the camera preview
    NatCam.Play(DeviceCamera.RearCamera);
    // Register for preview events
    NatCam.OnStart += OnStart;
    NatCam.OnFrame += OnFrame;
}

void OnStart () {
    // Display preview on a RawImage or plane?
    ...
    // Initialize the preview buffer and matrix
    pixelBuffer = new byte[NatCam.Preview.width * NatCam.Preview.height * 4];
    previewMatrix = new Mat(NatCam.Preview.height, NatCam.Preview.width, CvType.CV_8UC4);
}

void OnFrame () {
    // Update the preview data with the current preview frame
    NatCam.CaptureFrame(pixelBuffer);
    Utils.copyToMat (pixelBuffer, previewMatrix);
    // Do OpenCV stuff
    ...
}