embed for video must have audio description

Definition embed elements used for prerecorded video with synchronized audio (i.e. a movie, archived lecture) must have audio description of the video content.
Purpose
  • Text and audio descriptions provide a means for people who cannot see the video to understand the video content.
  • Some types of learning disabilities affect visual processing, text and audio descriptions provide an alternative way to understand the video content.
  • This rule covers the requirements of both WCAG 2.0 Success Criteria 1.2.3 and 1.2.5, that is why a text description of the video content cannot be used to satisfy this rule.
Required Yes for HTML4 Legacy Techniques ruleset mapping
WCAG 2.0 Success Criteria

1.2.3 Audio Description or Media Alternative (Prerecorded) (Level A, Primary Success Criterion)

Rule Category Audio/Video
Scope Element
Target Resources embed elements
  • embed
Techniques
  • Use the video element instead of the embed element for video only content, since the video element provides better support for audio description tracks.
  • Include an audio track in the video that describes the video content.
  • Use aria-describedby attribute to point to a text description of the video only content.
Manual Checks
  • When audio descriptions are enabled on the media player, check to make sure the audio description can be heard.
  • If there is a audio description make sure the description accurately describes the video content.
  • If there is a text description make sure the description accurately describes the video content.
Informational Links