Get RAW Bayer pixel data from CVPixelBufferRef

Question

I am using AVCaptureSession & AVCapturePhotoOutput to capture RAW photo data from device's camera in the kCVPixelFormatType_14Bayer_RGGB format.

I have got as far as getting the raw photo sample buffer in the AVCapturePhotoCaptureDelegate callback:

func capture(captureOutput: AVCapturePhotoOutput,
             didFinishProcessingRawPhotoSampleBuffer rawSampleBuffer: CMSampleBuffer?,
             previewPhotoSampleBuffer: CMSampleBuffer?,
             resolvedSettings: AVCaptureResolvedPhotoSettings,
             bracketSettings: AVCaptureBracketedStillImageSettings?,
             error: Error?) {

  guard let rawSampleBuffer = rawSampleBuffer else { return }

  guard let pixelBuffer = CMSampleBufferGetImageBuffer(rawSampleBuffer) else { return }
}

I am now attempting to follow the answers to this question to obtain pixel values from the CVPixelBufferRef but I cannot work out how to do this when using the 14 bit Bayer RGGB pixel format as opposed to the 32 bit RGB format mentioned in the answers.

Answer 1

First you need to find out the "Pixel format type" of the buffer. This is done with the CVPixelBufferGetPixelFormatType function.

The available types are listed here . In your case I'm guessing kCVPixelFormatType_14Bayer_BGGR .

Then you need to know how the data is stored. According to What is a CVPixelBuffer in iOS? it is

"Bayer 14-bit Little-Endian, packed in 16-bits, ordered RGR G... alternating with GBG B..."

Then you extract the pixels for Uint16 the same way they did for Uint8 in Get pixel value from CVPixelBufferRef in Swift .