audio description

narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone

Note 1: Audio description of video (opens in a new tab) provides information about actions, characters, scene changes, on-screen text, and other visual content.

Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description (opens in a new tab).)

Note 3: Where all of the video (opens in a new tab) information is already provided in existing audio (opens in a new tab), no additional audio description is necessary.

Note 4: Also called "video description" and "descriptive narration."

Source: WCAG 2.2 definition of “audio description” (opens in a new tab) (W3C)