WCAG 2.0 · Level AAA · Perceivable
1.2.8 Media Alternative (Prerecorded)
Manual verification
How to validate 1.2.8 by hand
Check for a complete text alternative for prerecorded synchronized media when evaluating the Level AAA media-alternative requirement.
Start with the extension result
Reopen the reported URL and reproduce the same state (for example, after expanding a menu or submitting a form). Use the result’s Highlight action when available, or its affected-element details and CSS selector, to find the reported content. Apply the checks below to that content and its context. If the element or state has changed, rescan and record that difference before deciding whether the finding still applies.
- Watch the video and listen to its audio; list dialogue, speaker changes, important sounds, actions, and visual information needed to follow the presentation.
- Read the supplied text alternative in sequence and compare it with the full media, including meaningful changes in scene and timing.
- Verify the alternative is clearly associated with the media and covers the complete presentation rather than only summarizing its topic.
Evidence to record
Record which audio or visual information is omitted and where the corresponding alternative appears.
Scope and exceptions
A short summary or transcript of dialogue may omit essential visual information. This Level AAA criterion is distinct from the less extensive alternatives permitted by other media criteria.
Record the review outcome
- Confirmed: the recorded evidence shows the requirement is not met in the tested page state, and no applicable exception explains it.
- Not reproduced: the reported issue is absent in the current state. Record the URL, state, and affected element you checked; this does not prove other pages or states conform.
- Needs more review: evidence is incomplete, the content requires human judgment, or an exception is uncertain. Record what remains to be checked instead of treating it as a pass.