WCAG Guideline 1.2.7: Extended Audio Description (Prerecorded) Explained
Estimated read time: 8–10 minutes
Guideline 1: Perceivable
The first WCAG principle is Perceivable. It means content must be available in forms users can perceive. Nothing should be invisible to all senses — sight, hearing, and touch via assistive technology all count.
Guideline 1.2: Time-based Media
Guideline 1.2 makes audio and video content accessible for all. The method is providing alternatives: transcripts, captions, and audio descriptions. Each alternative serves users who cannot access the original format.
What Is Guideline 1.2.7 Extended Audio Description (Prerecorded)?
"Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media."
Guideline 1.2.7 is a Level AAA requirement in the Web Content Accessibility Guidelines (WCAG) .
- All prerecorded video content with audio should have extended audio description if standard audio description is not sufficient.
- Extended audio description provides additional narration during pauses to describe important visual details.
- This is especially important for complex or fast-paced videos where standard audio description can't keep up.
This ensures that users who are blind or have low vision can fully understand your video content.
Why Does It Matter?
- Inclusivity: Extended audio description provides access for users who are blind or have low vision.
- Legal Compliance: This is a Level AAA requirement in WCAG 2.2.
- Usability: Enhances understanding for users who rely on audio cues to follow video content.
What Needs Extended Audio Description?
- Prerecorded video content with audio (movies, tutorials, online courses)
- Any synchronized media where standard audio description is insufficient
All such media should have extended audio description available.
How to Provide Extended Audio Description
- Add additional narration during pauses in the video
- Use professional audio description services or tools
- Make the audio description option easy to enable and hear
- Ensure descriptions are accurate and synchronized
For more, see W3C's audio description docs .
Common Mistakes to Avoid
- No extended audio description for complex video content
- Audio description that is out of sync or hard to hear
- Not making the audio description option easy to find
- Using unqualified narrators
Audit your site regularly and use accessibility checkers to ensure all video content has proper extended audio description. For more, see the Netflix Audio Description Style Guide v2.5 .
Differences Between A, AA, and AAA for Guideline 1.2.7 in WCAG 2.2
- Level A: No requirement for 1.2.7.
- Level AA: No requirement for 1.2.7.
- Level AAA: Requires extended audio description for all prerecorded video. Use it when standard audio description is not enough. This is the core requirement for 1.2.7 and is mandatory for AAA conformance.
For more, see the W3C’s official documentation for 1.2.7 Extended Audio Description (Prerecorded) .
Quick Checklist
- All prerecorded video content with audio has extended audio description if needed
- Audio description is accurate and synchronized
- Audio description option is easy to enable and hear
- Narrators are qualified and clear
- Tested with users and assistive technology
Summary
Guideline 1.2.7 ensures complex videos are fully accessible through extended audio descriptions. When a video is too fast-paced for standard description, pause the video and narrate instead. Make extended audio description part of your AAA video production process.