Prerecorded video needs an audio description or media alternative
Rule
media-alternative· Document, language & navigation · impact moderate · Static + live
Why it matters
At Level A, prerecorded video must offer either an audio description of its visual information or a full text alternative (a descriptive transcript) so people who cannot see it still get what it shows. This heuristic passes a <video> that has a <track kind="descriptions">, or whose surrounding container links to or mentions a transcript / audio-described version; with neither present the alternative almost certainly doesn’t exist. It cannot verify that a found transcript is complete, so it warns rather than fails. Same scope as media-captions: hidden players and silent-signature videos (muted with no native controls) are exempt.
How to fix
Add a <track kind="descriptions"> with timed descriptions, or place/link a descriptive transcript next to the player (e.g. inside the same <figure>) and name it "Transcript" so it is discoverable. An explicitly linked audio-described version of the video also satisfies 1.2.3.
Example
<video src="clip.mp4" controls></video>
<figure><video src="clip.mp4" controls></video><a href="/clip-transcript">Read the transcript</a></figure>
Example
<video src="tour.mp4" controls><track kind="captions" srclang="en" src="tour.vtt"></video>
<video src="tour.mp4" controls><track kind="descriptions" srclang="en" src="tour-ad.vtt"></video>
Captions alone don’t satisfy 1.2.3 — the text alternative must convey the visual information, which a descriptions track (or transcript) does.
WCAG success criteria
1.2.3 Audio Description or Media Alternative (Prerecorded) — Level A
Prerecorded video needs either an audio description of its visual information or a full text alternative (a descriptive transcript), so people who cannot see the video still get what it shows.
Standards
This rule contributes to the following standards:
WCAG A EN 301 549 Section 508
| Standard | Criteria |
|---|---|
| Section 508 | 1194.22(b) |
| EN 301 549 | 9.1.2.3 |