Audio Description
What Is Audio Description?
Audio description is a spoken narration added to a video that describes what is happening visually. It fills the gaps that dialogue leaves. In a software walkthrough where the presenter says "and then you just do this" while clicking through three screens, a viewer who cannot see the screen learns nothing at all. Audio description says which menu opened and which field was filled in.
What Gets Described
The rule of thumb is anything a viewer needs that only exists on screen: actions, scene changes, who is present, and above all text that is shown but never read aloud. Slide titles, figures on a chart, a phone number in the closing frame, a name badge. If the information appears only as pixels, it is invisible to anyone not watching.
Standard and Extended Description
Standard description fits into the natural pauses in the existing audio, which works when the video was paced with room to breathe. Extended description pauses the video to make time for narration, which becomes necessary for dense material such as training content or a demo where something happens every second. Choosing between them is a production decision made early, because retrofitting extended description into a finished edit is expensive.
Description Is Not a Transcript
A transcript records what was said. Captions put that same speech on screen as text. Audio description covers the opposite problem: information that was never spoken because the video simply showed it. A video can have perfect captions and still be unusable for a blind viewer, and this is one of the most common misunderstandings in video accessibility.
How It Affects Real Users
A blind employee is assigned mandatory compliance training delivered as video. The narrator says "review the four categories shown here" and moves on. The categories were only ever on the slide. Without description, that employee cannot complete training their job requires, and no amount of captioning fixes it, because the words were never spoken in the first place.
Where Audio Description Shows Up in an Accessibility Review
Reviewers check pre-recorded video for visual information that carries meaning and is not available any other way. Training material, product demos and recorded webinars attract the most findings, because they are the videos most likely to show something important instead of saying it. Where a description track is impractical, a full text alternative describing the visual content can serve the same purpose.