We did confirm that the memory was layed out in a ‘pitched’ configuration. We used the ‘stride’ value from the plane which was 768 to copy the data over using
for (int i=0; i < image_height; i++){
memcpy(&out_data[i * width], &in_data[i * stride], width);
}
But this still outputted a strange image, it wasn’t until we forced the stride to be 1024 that we were able to get a grayscale image that was correct.
Hope this helps someone else who might get stuck here