Is it possible to check difference between two captured frames from using VImage?

Question

I have a query when we start recording mac screen. I need to take only unique frames only not duplicate frames. Is possible to filter using Macos accelerate framework?

Answer 1

You could do this using vDSP. Apple's Finding the Sharpest Image in a Sequence of Captured Images sample code discusses sharing data between vImage and vDSP. Once you have a collection of the pixel values of two images, use subtract(_:_:) to find the difference followed by maximum(_:) to find the value of the maximum element. If the maximum is less than some threshold, the two buffers are identical.

Note that vDSP doesn't work on Pixel_8 values - if you're not capturing 32-bit per channel pixels, you'll need to convert to Float and that may have an overhead.

Of course, depending on how you're capturing the screen, you may not need vImage at all. For example, if you're getting CVPixelBuffer instances, use CVPixelBufferGetBaseAddressOfPlane to pass the data to vDSP.