CABC stands for Content Adaptive Backlight Control.
Normally an LCD’s backlight is set to the brightness that will make a white pixel fully illuminated. CABC automatically dims the backlight to the lowest level required for the brightest pixel on the display.
Simultaneously, the controller lightens the image by the same amount. Overall, there is no visible change in the image, but less power is used in the backlight for any image that does not contain a pure white pixel.
In this way, CABC reduces the overall average power needed by the display and backlight.