Audio description
Audio description is an extra narration track that describes important visual details in a video, such as actions, scene changes and on-screen text, for people who are blind or have low vision. The narration is placed in natural pauses in dialogue. Audio description is usually offered as an alternative audio track that viewers can select in the player.
Why it matters
Audio description makes video usable for blind and low-vision viewers, who would otherwise miss key visual information. It is part of common accessibility standards, so public sector buyers, schools and large enterprises may require it. Providing it widens audience reach and reduces legal risk.
How it works
- A writer notes important visual details, such as actions, text on screen and scene changes.
- Short descriptions are scripted to fit natural pauses in the dialogue.
- A narrator, or synthetic voice, records the descriptions.
- The described audio is mixed into a separate track or a separate version of the video.
- Viewers choose the described track from the player's audio menu.
What is the difference between audio description and closed captions?
Audio description narrates what is seen for people who cannot see the screen. Closed captions show what is heard for people who cannot hear the audio. They serve different audiences, and accessible video often needs both. A described track adds narration, while captions add on-screen text.
Is audio description required?
Often, for public-facing video. WCAG lists audio description for prerecorded video as a Level AA requirement, the level many laws and procurement rules reference. Exact obligations depend on country and sector. If key information is only shown visually, plan to describe it.
Where it's used
OTT services, government agencies, universities and corporate training teams add audio description so blind and low-vision viewers can follow films, lectures and training videos.
By the numbers
- WCAG lists Audio Description (Prerecorded) as success criterion 1.2.5 at Level AA. (Understanding SC 1.2.5 Audio Description (Prerecorded), W3C)
