audio must have alternative

Definition audio elements must have caption or text transcription of the audio content.
Purpose
  • Captions and text transcripts provide a means for people cannot hear the audio to understand the audio content.
  • Some types of learning disabilities affect speech perception, captions and text transcripts provide an alternative way to understand the audio content.
  • When the language of the audio is different than the native language of the listener, captions and text transcripts support the listner in understanding the audio content.
Required Yes for HTML4 Legacy Techniques ruleset mapping
WCAG 2.0 Success Criteria

1.2.1 Audio-only and Video-only (Prerecorded) (Level A, Primary Success Criterion)

Rule Category Audio/Video
Scope Element
Target Resources audio elements
  • audio
  • track
Techniques
  • Use the track element to add captioning to the audio content.
  • Use WebVTT to encode the timed stamped captioning information for the audio content.
  • Use aria-describedby to reference a text transcript of the audio content.
Manual Checks
  • When captions are enabled on the media player, check to make sure the captions visible.
  • If there is a caption make sure the captions accurately represents the audio content.
  • If there is a text transcript make sure the transcript accurately represents the audio content.
Informational Links