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

Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content.

In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)

Where all of the video information is already provided in existing audio, no additional audio description is necessary.

Also called "video description" and "descriptive narration."