What the standard says
For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such:
Why it matters
A podcast episode with no transcript is unavailable to Deaf users — and unindexable by search engines, which is the argument that usually gets it funded.
What a failure looks like
- failsA recorded webinar posted as audio only, with no transcript.
- failsA silent product demo video with no description of what is happening on screen.
How to fix it
- doPublish a transcript on the same page, not behind a download.
- doFor silent video, either a text description or an audio track describing the action.
How A11ySignal checks it
1 automated check runs against this criterion on every scan.
criticalaudio-caption<audio> elements must have a captions track
What a tool cannot tell you
No tool can tell whether a transcript is accurate or complete.