protected override void EncodeBlock(ARGBPixel *sPtr, VoidPtr blockAddr, int width)
        {
            CMPRBlock *dPtr = (CMPRBlock *)blockAddr;

            for (int y = 0; y < 2; y++, sPtr += (width * 4))
            {
                for (int x = 0; x < 8; x += 4)
                {
                    *dPtr++ = CMPRBlock.Encode(&sPtr[x], width, false);
                }
            }
        }