Audio description
A separate narration track describing visual content for blind and low-vision audiences — for video content where visuals carry information not conveyed in dialogue.
Audio description is to blind and low-vision audiences what captions are to deaf and hard-of-hearing audiences. A trained describer adds verbal narration of visual elements (slide content, on-screen text, demos, gestures) during natural pauses in the dialogue.
WCAG 2.2 has three audio-description criteria — 1.2.3 (Level A), 1.2.5 (Level AA), and 1.2.7 (Level AAA) — all applying to prerecorded media. Live events are not directly covered by these criteria; the practical mitigation is speaker training (describe visuals out loud).
For live events, audio description is rarely automated. The production-side complexity — knowing what's on screen at every moment — typically requires a human describer briefed in advance.