The criterion behind it
1.2.2 Captions (Prerecorded)
Pre-recorded video with sound needs captions.
Level A · EN 301 549 § 9.1.2.2
Why this check exists
Deaf and hard-of-hearing users, and the large share of people watching muted in public, get nothing from uncaptioned dialogue.
What usually triggers it
- failsAuto-generated captions left unreviewed, so product names and numbers are wrong.
- failsCaptions burned into a language track that the player cannot turn off.
How to fix it
- doShip a caption track (WebVTT) and check it against the script.
- doCaption the sounds that matter, not only the words: "[door slams]" can be the plot.
How it is reported
A11ySignal reports this at critical impact. Every failing element comes with its CSS selector and the markup that failed, so you can go straight to the line rather than hunting for it. Deque publishes the engine-level detail:
https://dequeuniversity.com/rules/axe/4.13/video-caption ↗
Check implemented by axe-core 4.13.0, © Deque Systems, MPL-2.0.