Dialogue enhancement is a playback feature, built into next-generation codecs like AC-4 and MPEG-H, that lets the listener raise the level of dialogue relative to music and effects — a direct fix for the common complaint that speech is hard to follow under loud backgrounds. It is possible because these codecs carry dialogue as separable objects or stems rather than baked into a single mix, so the decoder can boost just the speech by a user-chosen amount and re-render the result for the listener's speakers or headphones. This overlaps with accessibility (it especially helps hard-of-hearing viewers) but serves everyone watching in noisy rooms or on small speakers. It is one of the headline advantages of object-based audio over fixed channel mixes.
