Guide
Captions for accessibility
Captions are not a nice-to-have. For prerecorded video, WCAG 1.2.2 expects accurate, synchronized captions — and auto captions are only the first draft.
Last updated: 31 October 2026
TL;DR: Review the wording, timing and speaker labels. Add meaningful sounds. Do not treat an unreviewed machine transcript as a compliance certificate. For public-sector, education or regulated content, budget a human pass.
What WCAG 1.2.2 asks for
The success criterion applies to prerecorded synchronized media. Captions must be provided for audio content, and they must be accurate and synchronized. The W3C guidance explains the intent and the exceptions. This page is a practical summary, not legal advice.
- Accurate: names, numbers, jargon and dialogue must be right.
- Synchronized: captions must match the audio timing.
- Complete: include meaningful non-speech audio and speaker identification where needed.
Where auto captions fall short
| Problem | Fix |
|---|---|
| Names and brands misspelled | Search/replace and a quick read of the first minute. |
| No speaker labels | Use multi-speaker detection where available, then verify who is speaking. |
| Missing sounds | Add [music], [laughter], [applause] or a description where it carries meaning. |
| Lines too long / too fast | Split or merge cues and keep reading speed reasonable. |
| Punctuation missing | Fix sentence breaks; punctuation is part of readability. |
A review workflow
- Generate captions and fix the first ten seconds.
- Search for names, brands and acronyms.
- Check numbers, units and dates.
- Add speaker labels and meaningful sounds.
- Check timing and line length on a phone-sized preview.
- Export SRT/VTT or burn in, depending on the player.
Captions, subtitles and SDH
Subtitles often translate dialogue. Captions are designed for accessibility and include non-speech information. SDH (Subtitles for the Deaf and hard of hearing) adds speaker IDs and sound descriptions. If accessibility is the goal, deliver captions or SDH, not just a translated subtitle track.
Sources
FAQ
Are auto captions WCAG compliant?
Not automatically. WCAG 1.2.2 requires accurate, synchronized captions. Unreviewed machine captions can be a starting point, but names, timing, speaker labels, punctuation and meaningful sounds need review.
Do I need closed captions or subtitles?
If the audience includes Deaf or hard-of-hearing viewers, use captions that include non-speech audio and speaker labels. Subtitles that only translate dialogue may not meet the need.
What accuracy is good enough for accessibility?
There is no universal number. The captions must convey the dialogue and relevant sounds accurately and stay synchronized. For regulated content, use a human review and follow the applicable standard.