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What is audio description?
Audio description is extra narration that tells blind and low-vision viewers what is happening on screen when the soundtrack does not say it.
Definition
Audio description (AD), also called described video or descriptive audio, is a narrated track that describes the important visual parts of a video: actions, people, settings, on-screen text, charts and scene changes. It is usually spoken in the natural pauses of the soundtrack.
Who it is for
Audio description is designed for people who are blind or have low vision. It also helps people with some cognitive or learning disabilities, and anyone listening without watching, such as while driving or cooking.
A simple example
A lecturer says "as you can see here" and points to a chart. Without description, a blind student hears silence. With description, a narrator adds: "A bar chart shows enrollment rising from 2,000 in 2019 to 3,500 in 2024."
Standard vs extended audio description
Standard description fits in existing pauses without changing the video's length. Extended description pauses the video to make room when there are not enough natural gaps, which is common in lectures and tutorials. WCAG treats these as separate criteria: 1.2.5 (AA) and 1.2.7 (AAA).
Is audio description required?
Accessibility standards such as WCAG 2.1 Level AA require audio description for prerecorded video. Laws and rules that reference WCAG 2.1 AA, including the U.S. ADA Title II rule for state and local governments and EN 301 549 under the European Accessibility Act, therefore generally expect it. See our WCAG guide.
How audio description is made
Traditionally a trained describer writes a script and a voice artist records it. AI tools now draft and voice descriptions automatically, which makes large backlogs affordable; a quick check by the publisher is still wise for high-stakes content.