Perceivable / 1.2 Time-based Media
1.2.4Captions (Live)
Level AALive audio in synchronized media -- breaking news, live streams, and the like -- needs real-time captions just as prerecorded content does. Some delay is unavoidable, but the goal is that viewers who are deaf or hard of hearing aren't left out of live broadcasts.
Note
A detailed commentary for this success criterion is not yet available. In the meantime, this page lists related patterns, techniques, and links to the normative sources.
Related Techniques
Specific implementation techniques for meeting this success criterion. This site doesn't include the full text, so follow the links to the original W3C documents.
Sufficient Techniques(5)
- G9: Creating captions for live synchronized media(opens in a new tab)waic.jp(opens in a new tab)
- G87: Providing closed captions(opens in a new tab)waic.jp(opens in a new tab)
- G93: Providing open (always visible) captions(opens in a new tab)waic.jp(opens in a new tab)
- SM11: Providing captions through synchronized text streams in SMIL 1.0(opens in a new tab)waic.jp(opens in a new tab)
- SM12: Providing captions through synchronized text streams in SMIL 2.0(opens in a new tab)waic.jp(opens in a new tab)
Normative References
- Success Criterion 1.2.4 Captions (Live) — WCAG 2.2(opens in a new tab)The normative requirement text.
- Understanding Captions (Live) — W3C(opens in a new tab)Official guidance on intent, examples, and techniques.