1.2 Time-based Media · Perceivable
WCAG 1.2.4 Captions (Live)
Level AA
Live audio in a synchronised media stream must be captioned in real time so deaf and hard-of-hearing viewers can follow.
Common failures
- Live webinars stream without any captioning option.
- An ASR service is enabled but its accuracy hasn't been measured.
How to fix
- Hire a real-time captioner (CART) for high-stakes live events.
- For routine streams, use a quality-monitored ASR pipeline with a human checking accuracy.
Related criteria
- WCAG 1.2.2 Captions (Prerecorded) Level A
- WCAG 1.2.9 Audio-only (Live) Level AAA