Advanced Contrast Enhancer is a TV feature that automatically adjusts the contrast between dark and bright areas of the screen.
It makes dark scenes look deeper and bright scenes more vivid, so the picture feels more realistic. For example, when watching a movie with a night sky, stars will shine brightly while the sky stays dark instead of looking gray.
This feature is especially useful on non-OLED TVs, which rely on backlights. It gives them a “pseudo HDR” effect even if the content isn’t HDR.
See also: Contrast Ratio, HDR, Local Dimming