Disabilities Affected: Visual
Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description must be provided for all prerecorded video content in synchronized media.
Why It Matters
Standard audio description (WCAG 1.2.5) fits narration into existing pauses. Sometimes, there isn’t enough silent time in the main audio track to describe complex visual scenes or actions adequately. Extended audio description solves this by temporarily pausing the main video and audio to insert longer descriptions, then resuming. This ensures blind users don’t miss critical visual information due to time constraints.
Fixing the Issue
Identify parts of the video where visual information is crucial but pauses are too short for standard audio description. Create a version of the video where the main action freezes/pauses at these points, the extended description is played, and then the main video resumes. This requires careful editing in post-production. Provide this version as an alternative to the standard video.
Good Code Example
Linking to a version of the video with extended audio description:
-
<video controls width="640" height="360" poster="video-poster.jpg">
<source src="main-video.mp4" type="video/mp4">
<track label="English Captions" kind="captions" srclang="en" src="captions_en.vtt" default>
<track label="English Audio Description" kind="descriptions" srclang="en" src="description_en.vtt">
Your browser doesn't support embedded videos.
</track></track></source><p>
<a href="main-video-with-extended-ad.mp4">Watch version with Extended Audio Description</a>
</p></video>
Bad Code Example
A video with complex visuals and short pauses, only offering standard AD:
-
<video controls width="640" height="360" src="fast-paced-visuals.mp4">
<track label="English Captions" kind="captions" srclang="en" src="captions_en.vtt">
<track label="English Audio Description" kind="descriptions" srclang="en" src="description_en.vtt">
</video>
