Does each prerecorded time-based medium have, where necessary, a synchronized audio description (except in special cases)?
A blind user watches a video tutorial. The instructor shows screenshots, draws diagrams, points to interface areas. The soundtrack describes none of this. Without audio description, half the content disappears. Synchronized audio description fills these silences: a voice describes the important visual elements that dialogue leaves unspoken.
This criterion covers two categories of media. "Video-only" videos (silent screencast, soundless animation) and synchronized media (video with dialogue or narration). In both cases, if visual information is not conveyed by the existing audio, audio description is required. If dialogue already describes what's happening on screen, nothing more is necessary.
Two implementations are accepted by RGAA: audio description integrated directly into the media, or an alternative version with audio description accessible via a button or adjacent link. In native HTML, <track kind="descriptions"> associates a WebVTT file with the video player. For videos hosted on YouTube or Vimeo, the alternative version often remains the only practical option.
No description, no access. Audio description does not recite everything: it only covers the gap between what eyes see and what ears hear.
2 tests to verify the presence of synchronized audio description
Audio description of video-only media
For each video without an audio track (silent screencast, silent animation) whose visual content conveys information:
- Check whether the player offers an activatable audio description track (e.g.
<track kind="descriptions">or option in third-party player). - If not, look for a button or link placed immediately before or after the video in the document, providing access to an alternative version with audio description.
- If neither option is present, the test fails.
- If at least one option is available for each relevant video, the test is validated.
Audio description of synchronized media
For each video with an audio track (filmed lecture, tutorial with narration, demonstration) whose visual content is not limited to what dialogue describes:
- Close your eyes and listen only to the soundtrack. If important information remains incomprehensible, audio description is necessary.
- Check whether an audio description track is available and activatable in the video player.
- If not, check for a button or adjacent link providing access to an alternative version with audio description.
- If neither is present for a relevant medium, the test fails.
Examples
❌ Non-compliant : Synchronized video without audio description or alternative
<video controls width="800">
<source src="tutoriel-interface.mp4" type="video/mp4">
<source src="tutoriel-interface.webm" type="video/webm">
<track kind="subtitles" label="French" src="sous-titres.vtt" srclang="fr">
</video>
<p>Watch our hands-on tutorial.</p>This video offers subtitles, which addresses criterion 4.3, but provides no audio description. A blind user hears the instructor's voice but has no idea what they are manipulating on screen. <track kind="subtitles"> does not replace <track kind="descriptions">: these are two distinct tracks for two different needs.
✅ Compliant : Video with WebVTT audio description track
<video controls width="800" poster="tutoriel.png">
<source src="tutoriel-interface.mp4" type="video/mp4">
<source src="tutoriel-interface.webm" type="video/webm">
<track kind="subtitles" label="Subtitles" src="sous-titres.vtt" srclang="fr">
<track kind="descriptions" label="Audio description" src="tutoriel-audiodesc.vtt" srclang="fr">
</video>
<p>Watch our hands-on tutorial.</p>The <track kind="descriptions"> tag associates a WebVTT audio description file. When the user activates this track, important visual elements are described in the pauses of dialogue — for example: "The instructor clicks on the Settings menu, top right." The visual content becomes accessible without watching the screen.
✅ Compliant : Alternative version via adjacent link for a hosted video
<figure>
<iframe
src="https://www.youtube.com/embed/abc123"
title="Presentation of new features"
width="560"
height="315"
allowfullscreen>
</iframe>
<figcaption>
Presentation of new features (8 min) —
<a href="/videos/presentation-with-audio-description">
Version with audio description
</a>
</figcaption>
</figure>For a YouTube video where it is impossible to inject an audio description track, a link to an alternative version is a solution compliant with RGAA. The link is placed directly below the video, in the caption — immediately accessible in the viewing flow. A link at the bottom of the page or in a FAQ would not satisfy the adjacency requirement.
Tips and pitfalls
⚠️ Confusing subtitles and audio description
Subtitles (criterion 4.3) transcribe speech for deaf people. Audio description describes the visual for blind people. These are two distinct tracks, two distinct criteria. A medium may require both. <track kind="subtitles"> never replaces <track kind="descriptions">.
⚠️ Media exempt under special cases of criterion 4.1
Some media do not require audio description. A purely decorative medium with no informative content to convey is exempt. Likewise, if the medium itself is an alternative to existing textual content and is clearly identified as such on the page, it is not subject to this criterion. Systematically verify whether the visual adds something that the surrounding text does not already say.
⚠️ The link to the alternative version must be adjacent, not simply present
RGAA requires that the alternative version be accessible via a button or link immediately before or after the medium in the document flow. A link placed in the footer, in a hidden accordion, or two navigation clicks away is not compliant. In audits, this is the most frequent error on this criterion.
⚠️ Dialogue already describes everything: no audio description required
If an instructor says "I'm now clicking the blue Save button, top right of the screen" while performing the action, the visual information is already in the audio track. Audio description only covers what eyes see and ears do not hear. An audio test with eyes closed is sufficient to decide.
💡 Support for <track kind="descriptions"> remains partial in practice
Few native media players automatically expose the descriptions track to screen readers. Experience varies depending on the browser and AT combination used. For maximum coverage, combine the WebVTT track with a link to an alternative version. This is not a double RGAA obligation, but in practice, this is the most robust strategy.
⚠️ Media published before September 23, 2020
European Directive 2016/2102, transposed into French law, sets September 23, 2020 as the deadline for existing content. Media published before this date could benefit from an exemption for disproportionate burden. Any media published or updated after this date must comply with criterion 4.5 without exception.
Frequently asked questions
How to determine whether a video requires synchronized audio description according to RGAA?
Close your eyes and listen only to the soundtrack. If you understand all the informative content without watching, audio description is not necessary. As soon as visual information is missing from the audio — an action shown but not described, text displayed on screen, a significant scene change — audio description becomes mandatory.
What is the difference between audio description RGAA 4.5 and text transcript of criterion 4.1?
Text transcript (criterion 4.1) is a static document that restores all audio and visual content as text. Synchronized audio description is an audio track synchronized to the video timeline. The two are complementary: the transcript allows searching and speed reading, audio description offers a real-time viewing experience for screen reader users.
How to use a WebVTT file with kind="descriptions" to meet RGAA criterion 4.5?
Yes, if the file is properly synchronized and covers all important visual elements. Compliance with criterion 4.5 concerns the presence of audio description, not the technique. The relevance of content is evaluated separately by criterion 4.2. An empty or incomplete WebVTT file validates presence but fails on relevance.
How to audit synchronized audio description of a video according to RGAA criterion 4.5?
Proceed in two stages. First, identify visual elements that carry information: actions, on-screen text, important expressions, scene changes. Next, activate the audio description track or watch the alternative version, and verify that each of these elements is described at the right time. If an important visual element is not covered, criterion 4.5 fails. If the description is present but inaccurate or incomplete, it is criterion 4.2 that applies.
How to provide RGAA-compliant synchronized audio description for a video hosted on YouTube?
YouTube allows adding description tracks via its subtitle manager, but restitution by screen readers remains random depending on configurations. Most reliable solution: host an alternative version of the video with audio description integrated into the main audio track, then place a link to this version directly next to the YouTube iframe on your page.