Goal
Enable people who are blind or have low vision to understand visual content in videos.
Success Criterion · WCAG 1.2.3
Audio Description or Media Alternative (Prerecorded)
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.
Level AWCAG 2.0Perceivable1.2 · Time-based Media
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What to do
Provide either audio descriptions or a full text alternative that describes all visual information in prerecorded videos.
Why it matters
Visual actions, scene changes, and on-screen text are invisible to users who cannot see the video.
Success criterion
What WCAG 1.2.3 requires
Summarized directly from the official Understanding document so teams can quote the requirement accurately.
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.
Intent
Why WCAG created this requirement
- Audio descriptions narrate visual information (actions, scene changes, on-screen text, facial expressions) during pauses in dialogue.
- A media alternative provides the same information in text form—essentially a screenplay or extended transcript with visual descriptions.
- This criterion offers a choice: audio description OR media alternative, allowing flexibility based on content type and resources.
- The goal is ensuring blind and low vision users can fully understand what is happening visually in the video.
Benefits
Who gains when you pass
- People who are blind can hear descriptions of visual elements they cannot see.
- People with low vision can supplement what they partially see with audio descriptions.
- People who have difficulty interpreting visual information benefit from explicit verbal descriptions.
- Text alternatives can be accessed via braille displays or read at the user's own pace.
- Text alternatives are searchable and can be translated into other languages.
Why it matters
User impact when this criterion fails
Summaries drawn from the Understanding document help you socialize impact statements with product stakeholders.
Without audio descriptions or media alternatives, blind users miss all visual-only information: actions, locations, expressions, on-screen text, and scene transitions.
Critical plot points, demonstrations, or instructions conveyed only visually become completely inaccessible.
Users relying on screen readers cannot perceive graphs, charts, demonstrations, or physical interactions shown on screen.
Educational and training videos lose their effectiveness when visual demonstrations cannot be understood.
Exception guidelines
Use the WCAG 1.2.3 exceptions correctly
Document the rationale for each exception and note which alternative support you provide.
Media alternative for text
If the video is itself an alternative for existing text content (like a video summary of an article), it is exempt.
Requirement
The media must be clearly labeled as a media alternative, and the primary text content must be present and accessible nearby.
Overview
Prerecorded videos with synchronized audio must provide either: (1) Audio descriptions—a narration track that describes important visual content during natural pauses in dialogue, or (2) A full text alternative (like a detailed transcript or screenplay) that includes descriptions of all visual information along with the dialogue. This criterion gives content authors flexibility in how they make visual video content accessible to blind users.
- Audio descriptions are inserted during natural pauses in dialogue—they should not overlap with important audio.
- Media alternatives must include ALL visual information, not just a summary—actions, settings, expressions, on-screen text.
- Either option satisfies this criterion; you do not need to provide both (though both is ideal).
- For WCAG Level AA, criterion 1.2.5 specifically requires audio descriptions, while this Level A criterion allows either option.
- Describes visual content that is not already conveyed through the existing audio track.
Reference: All summaries and highlights originate from Understanding WCAG 1.2.3 and the W3C quick reference.
Fast facts
- Conformance level
- Level A
- WCAG version introduced
- WCAG 2.0
- Principle
- Perceivable
- Guideline
- 1.2 · Time-based Media
Examples
Make success tangible for teams
Share pass/fail snapshots to coach designers, engineers, QA, and content authors.
Cooking tutorial
Pass
Audio description: "She chops the onion into small cubes, then adds them to the heated pan. The onions sizzle as they hit the oil."
Fail
The chef demonstrates techniques visually while only saying "like this" or "see how I do it" with no description of what is being shown.
Software tutorial
Pass
Media alternative transcript includes: "The presenter clicks the Settings icon in the top-right corner. A dropdown menu appears with options: Profile, Preferences, and Logout."
Fail
Transcript only includes spoken dialogue: "Now I'll click here and select this option" without describing what is clicked or selected.
Documentary
Pass
Audio description during a pause: "Archive footage shows crowds gathered in the town square. Signs read 'Peace Now' and 'End the War.'"
Fail
Historical footage plays with dramatic music but no description of what the footage shows.
Training video
Pass
Either an audio-described version OR a full text alternative with descriptions like: "[Diagram showing workflow: Step 1 leads to Step 2 via approval gate]"
Fail
Complex diagrams and flowcharts are shown on screen while the narrator only says "as you can see in this diagram" without describing it.
Evidence to keep
Document conformance decisions
Capture artifacts for VPATs, procurement reviews, and regression testing.
- Create a video inventory noting which videos have audio descriptions, media alternatives, or both.
- Document the description script alongside each video asset.
- Establish guidelines for writing audio descriptions: what to describe, timing, voice/tone.
- Store transcript files that include both dialogue and visual descriptions.
- Record evidence of audio description availability (screenshots of player controls, links to alternatives).
Official resources
Deep dives and supporting material
Keep these links handy when writing acceptance criteria or responding to audits.
Understanding 1.2.3
Official W3C interpretation, techniques, and intent for this criterion.
Quick Reference 1.2.3
Filterable list of sufficient techniques and failures.
Technique G69
Providing an alternative for time-based media.
Technique G78
Providing a second, user-selectable audio track that includes audio descriptions.
Technique G173
Providing a version of a movie with audio descriptions.
Audio Description Project
American Council of the Blind resource for audio description best practices.
Implementation checklist
Capture progress and blockers
- Identify all prerecorded synchronized media (video with audio) that contains important visual information.
- Decide whether to provide audio descriptions, a media alternative (text), or both.
- For audio descriptions: write a script describing visual elements during pauses in dialogue.
- Record the audio description narration and synchronize it with the video.
- For media alternatives: create a detailed transcript including all dialogue AND descriptions of visual content.
- Ensure descriptions cover: actions, scene changes, on-screen text, character expressions, and any visual information essential to understanding.
- Provide a mechanism to enable/disable audio descriptions or link to the media alternative.
- Test with blind users to ensure descriptions adequately convey the visual experience.
Testing ideas
Prove conformance with evidence
- Identify all prerecorded videos with synchronized audio.
- Determine if significant visual information is conveyed that is not in the audio track.
- Verify either audio descriptions OR a media alternative is available.
- For audio descriptions: listen to the described version and verify visual information is adequately conveyed.
- For media alternatives: read the text and verify all visual information is described, not just dialogue.
- Check that descriptions are synchronized appropriately and do not overlap with important dialogue.
- Test with a screen reader to ensure the alternative is accessible.
- Compare the visual content against the descriptions to ensure nothing essential is missing.
Related success criteria
More from Time-based Media (1.2)
WCAG 1.2.1Audio-only and Video-only (Prerecorded)Level AWCAG 1.2.2Captions (Prerecorded)Level AWCAG 1.2.4Captions (Live)Level AAWCAG 1.2.5Audio Description (Prerecorded)Level AAWCAG 1.2.6Sign Language (Prerecorded)Level AAAWCAG 1.2.7Extended Audio Description (Prerecorded)Level AAAWCAG 1.2.8Media Alternative (Prerecorded)Level AAAWCAG 1.2.9Audio-only (Live)Level AAA