1.2.5 Audio Description (Prerecorded)
Level: AA | Principle: Perceivable | Since: WCAG 2.0 | Automation: Manual
What This Means
All pre-recorded video content with audio must have an audio description track. Audio descriptions are narrated explanations of important visual information — actions, scene changes, on-screen text, and visual cues — inserted during natural pauses in the dialogue.
This criterion is stricter than 1.2.3. While 1.2.3 (Level A) allows either an audio description or a full text alternative, 1.2.5 (Level AA) specifically requires an audio description track. The audio description must be synchronized with the video so blind users can follow along in real-time.
Who This Affects
- Blind users — audio descriptions narrate what is happening visually so they can follow the full content
- Low-vision users — they may miss on-screen details that audio descriptions make explicit
- Users with cognitive disabilities — additional narration can aid comprehension of complex visual sequences
Common Pitfalls
1. Video with no audio description track
<!-- Bad: only captions are provided, no audio description -->
<video controls src="training-video.mp4">
<track kind="captions" src="captions.vtt" srclang="en" label="English">
</video>
2. Audio description that misses key visual information
WEBVTT
00:00:30.000 --> 00:00:33.000
The presenter advances the slide.
<!-- Bad: does not describe what the new slide contains -->
3. Audio description that talks over dialogue
Audio descriptions should be inserted during natural pauses in dialogue. If there are no pauses, an extended audio description version of the video may be needed (covered by 1.2.7, Level AAA).
4. Only providing a text transcript instead of audio description
At Level AA, a text alternative alone does not satisfy this criterion. An actual audio description track must be available.
How to Fix
Add an audio description track
<!-- Good: audio description track provided -->
<video controls src="training-video.mp4">
<track kind="captions" src="captions.vtt" srclang="en" label="English" default>
<track kind="descriptions" src="descriptions.vtt" srclang="en" label="Audio descriptions">
</video>
Write effective audio descriptions
WEBVTT
00:00:05.000 --> 00:00:09.000
A woman in a lab coat stands in front of a whiteboard filled with chemical formulas.
00:00:22.000 --> 00:00:26.000
She draws a diagram showing two molecules bonding. An arrow points from reactant A to product C.
00:01:15.000 --> 00:01:19.000
On-screen text reads: "Key takeaway — catalysts lower activation energy by 40%."
00:02:00.000 --> 00:02:04.000
The screen splits to show a before-and-after comparison of reaction rates.
Provide a separate described version
<!-- Good: link to a version with audio description mixed into the main audio -->
<video controls src="training-video.mp4">
<track kind="captions" src="captions.vtt" srclang="en" label="English" default>
</video>
<p>
<a href="training-video-described.mp4">Watch version with audio descriptions</a>
</p>
How to Test
- Identify all prerecorded videos with audio on the page.
- Check the video player for an audio description track option (often a button labeled "AD" or in the settings menu).
- Enable the audio description and watch the video. Verify it narrates key visual information: scene changes, on-screen text, character actions, and data visualizations.
- Confirm the descriptions are inserted during natural pauses without talking over dialogue.
- If a separate described version is provided instead, verify it is clearly linked near the video player.
- Pass: Every video offers an audio description track (or described version) that covers all significant visual content.
- Fail: Any video lacks an audio description option, or the description misses key visual information.
axe-core Rules
No automated axe-core rules. This criterion requires manual testing.