WCAG 1.2.3 Audio Description or Media Alternative (Prerecorded)

What it asks

Captions cover what can be heard. This rule covers what can be seen. When a video shows something that matters, such as a presenter pointing at a slide, a step performed on screen in a tutorial or a character’s expression in a story, people who cannot see it need another way to get that information.

At Level A there are two routes. The first is audio description: narration, added to the soundtrack or provided as a separate track, that describes the important visual content in the gaps between the dialogue. The second is a media alternative: a full text version of the video, including the dialogue, the sounds and a description of what is shown, in order. Either one satisfies 1.2.3.

At Level AA, 1.2.5 Audio Description (Prerecorded) removes the second route. A text alternative no longer counts; the video needs audio description. In practice, most organisations working towards AA skip the text route and provide description.

If the video has no important visual information beyond what is said, for example a talking head interview, the soundtrack already carries everything and no extra description is needed. And as with the other 1.2 criteria, a video that is itself a labelled alternative for text is exempt.

Its official name is success criterion 1.2.3 Audio Description or Media Alternative (Prerecorded), at Level A. It was added in WCAG 2.2, under guideline 1.2 Time-based Media and the principle Perceivable. The W3C’s normative text says, in part:

“An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.”

From WCAG 2.2, W3C. Full explanation: Understanding 1.2.3 Audio Description or Media Alternative (Prerecorded).

Who it helps

People who are blind or have low vision, who hear the dialogue but miss everything that is only shown. In a software tutorial that can be every step. People with cognitive disabilities who benefit from hearing what is happening named.

The text alternative also helps deaf-blind people, who can read it through braille, and anyone who wants to search or skim the content.

What passes and what fails

These pass

• A tutorial video whose narrator says what they are doing at each step, so the soundtrack already describes the visuals.
• A video with a second audio track, selectable in the player, that describes the visual content.
• A described version of the video offered beside the original.
• A full text alternative under the video, with dialogue, sounds and descriptions of each scene in order, and a clear link between the two.
• An interview where nothing is shown that is not said.

These fail

• A tutorial video where actions are only shown on screen and the narration says "click here" and "then this".
• A "Read more" link next to a video that leads to a marketing summary, not a text version of the video.
• A product video that shows features with music only, and no description anywhere.
• A video where on-screen text, such as a price or a date, is never spoken.

How to test it by hand

1. Find every recorded video with sound on the page.
2. Watch each one with your eyes closed, or with the screen off. Note every moment where something was shown that you would need to know and that was not said.
3. If there were such moments, look for a described audio track in the player, or a separate described version.
4. If there is none, look for a text alternative on the page or linked from it. Read it against the video. Does it cover the dialogue, the sounds and the visuals, in order?
5. Check that any text alternative is clearly linked to the video it describes.
6. Note each video that has important visual content and neither route.

What automated testing can decide

What a machine can decide

Automated testing can find the videos and see whether a description track is declared in the player, which is positive evidence that one route exists. It can also find a link near the player that looks like a transcript or text version, and point a reviewer at it.

What it cannot

The absence of a description track is not the absence of a description. Many described videos carry the narration in their main soundtrack, and nothing in the markup says so. Automated testing cannot know whether a video even has visual content that needs describing, and it cannot confirm that a link called "Transcript" leads to a full alternative for this video rather than a summary. So this criterion cannot be failed from the page alone.

How Dreven handles it

Dreven finds the recorded videos on your pages and shows you each one with whatever description or text alternative was found beside it.

A reviewer watches the video, decides whether its visual content needs describing, and records the result. The report says which route the site uses, because buyers check this claim.

No automated check makes a site conform. In Dreven, a person reviews the results and signs the report.

Related criteria

• 1.2.5 Audio Description (Prerecorded) (Level AA). At Level AA only the audio description route remains.
• 1.2.2 Captions (Prerecorded) (Level A). The same video also needs captions for what is said.
• 1.2.1 Audio-only and Video-only (Prerecorded) (Level A). Silent video needs a text or audio alternative of its own.
• 1.1.1 Non-text Content (Level A). Still images need text that serves the same purpose.

Questions people ask

All WCAG 2.2 criteria, in plain words