WCAG 1.2.3 Audio Description or Media Alternative: What Websites Need to Know

WCAG 1.2.3 Audio Description or Media Alternative explains what to provide for prerecorded audio-visual content so people who are blind or have low vision can get the same information. This page summarises the rule, shows when it applies, gives practical implementation steps, and lists common mistakes to avoid.

What WCAG 1.2.3 requires

WCAG 1.2.3 is a Level A success criterion in WCAG 2.0 that covers prerecorded synchronized media. For such media you must provide one of these alternatives that communicates the important visual information:

• an audio description track inserted into natural pauses,
• an extended audio description that plays separately, or
• a full media alternative such as a text description or a text transcript that conveys the visual information.

The alternative must present key visual content needed to understand the media. Simple captions are not a substitute for audio description unless they describe visual-only information.

When WCAG 1.2.3 applies

Apply WCAG 1.2.3 to prerecorded synchronized audio-visual content. That includes marketing videos, recorded lectures, training modules, and product demos that combine sound and images. It does not require live events. Separate audio-only files are not within this criterion.

Types of acceptable alternatives

Audio description (embedded)

An embedded audio description track is narration placed into pauses in the original soundtrack. It is the most natural experience because both original audio and descriptive narration play in one timeline.

Extended audio description (separate track)

An extended audio description is a longer separate file that narrates the visual details at a slower pace. It can be provided as a second audio track that users can choose to play instead of the main soundtrack.

Media alternative (text)

A media alternative can be a timed text transcript or a full text description that conveys all important visual information. Use a descriptive transcript for short videos with limited visual content. Use a longer textual description for complex visuals where timing is less important.

How to meet WCAG 1.2.3 — step by step

1. Audit your prerecorded videos and label each as low, medium or high visual dependency. Low means visuals are decorative. High means visuals carry crucial information beyond the audio.
2. For high dependency videos, create an embedded audio description track or an extended description. For medium dependency, a descriptive transcript may be enough.
3. Author the description: name speakers when needed, describe actions, settings, facial expressions, and on-screen text that matters. Keep descriptions concise and placed in natural pauses.
4. Deliver the alternative in accessible formats. For HTML5 video add a <track kind="descriptions" src="descriptions.vtt" srclang="en" label="Audio description"> or provide a separate audio file and a clearly visible link next to the player. For text alternatives provide a linked transcript or a descriptive page near the media.
5. Test with assistive technology and with users who are blind or have low vision. Confirm the description is discoverable, accurate, and timed or located appropriately.

HTML example

Simple HTML5 example showing a description track. This snippet assumes a WebVTT file labelled for descriptions.

<video controls> <source src=“video.mp4” type=“video/mp4”> <track kind=“descriptions” src=“descriptions.vtt” srclang=“en” label=“Audio description”> </video>

Deciding between audio description and a media alternative

Choose audio description when the visuals are time dependent and affect comprehension. Choose a text alternative when visuals are static or when a full textual description can convey the same information without timing, for example a product specification video with simple shots.

Testing and verification

Automated tools can only confirm the presence of a description file or a transcript. They cannot judge quality. Manual checks should include:

• Playing the description track with the video to check timing and completeness.
• Checking that links and controls for the alternative are perceivable by screen readers and keyboard users. Use a screen reader during testing.
• Asking at least one person who is blind or has low vision to review samples and give feedback.

Common mistakes to avoid

• Equating captions with audio description. Captions transcribe speech and sounds. They do not describe visual actions unless explicitly added.
• Hiding description links in submenus or behind JavaScript-only controls that are not keyboard accessible.
• Providing a poor quality transcript that omits visual information or uses vague language such as “visuals show” without detail.
• Failing to test the description with assistive technologies and real users.

Quick compliance checklist for WCAG 1.2.3

• Inventory prerecorded videos and mark visual dependency.
• Provide embedded audio descriptions or extended descriptions for high-dependency videos.
• Provide a descriptive transcript or media alternative where appropriate.
• Use standard delivery methods such as HTML5 <track kind="descriptions"> or a visible link to an audio file or transcript.
• Verify discoverability with a screen reader and with keyboard-only navigation.
• Document the choice and location of alternatives for each video in your accessibility statement.

Practical examples

Short product demo (20 seconds)

If the demo shows a single product rotation and the audio explains the features, a short descriptive transcript placed next to the player is often sufficient. If the visuals show important button presses or model interactions, provide an audio description.

Training module (10 minutes)

Training often uses visuals to teach procedures. Provide embedded audio description or an extended audio description. Also provide a full transcript for review and searching.

Record keeping and policy

Keep a simple register that logs each video, the alternative provided, the file locations, and last review date. Update the register when content changes. Note that public sector bodies in the UK must follow the government accessibility regulations which reference WCAG standards.

Where WCAG 1.2.3 fits with other success criteria

WCAG 1.2.3 complements captions and transcripts in 1.2.2 and 1.2.1. It focuses on visual information for prerecorded content. For live media other criteria apply. Use WAI-ARIA properly for controls, but ARIA does not replace content-level descriptions.

Final notes

WCAG 1.2.3 is about giving equivalent access to visual information in prerecorded media. Choose the method that preserves meaning and timing. Test with real users and document your approach so content stays accessible as it changes.