What the standard says
Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
Why it matters
Deaf and hard-of-hearing users, and the large share of people watching muted in public, get nothing from uncaptioned dialogue.
What a failure looks like
- 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 A11ySignal checks it
1 automated check runs against this criterion on every scan.
criticalvideo-caption<video> elements must have captions
What a tool cannot tell you
Caption accuracy is a human judgement. A scanner can only see that a track exists.
Also under 1.2 Time-based Media
- 1.2.1 Audio-only and Video-only (Prerecorded)
- 1.2.3 Audio Description or Media Alternative (Prerecorded)
- 1.2.4 Captions (Live)
- 1.2.5 Audio Description (Prerecorded)
- 1.2.6 Sign Language (Prerecorded)
- 1.2.7 Extended Audio Description (Prerecorded)
- 1.2.8 Media Alternative (Prerecorded)
- 1.2.9 Audio-only (Live)