Audio Description (Prerecorded) (Level AA)

Videos often contain important visual information like actions, settings, text, or expressions that are not spoken aloud. For people who cannot see what’s happening on the screen, audio descriptions make that content understandable.

An audio description is a spoken narration that explains key visual details during natural pauses in dialogue. It allows people who are blind or have low vision to follow the story or information being presented.

Example

Describer: A title appears, “Teaching Evolution Case Studies. Bonnie Chen.” A teacher shows photographs of birds with long, thin beaks.
Bonnie Chen: “These photos were all taken at the Everglades.”
Describer: The teacher hands each student two flat, thin wooden sticks.
Bonnie Chen: “Today, you will pretend to be a species of wading bird that has a beak like this.”
Describer: The teacher holds the sticks to her mouth, making the shape of a beak.

Here, the describer narrates what’s visually happening so that someone who can’t see the screen still understands the lesson.

WCAG Success Criterion

1.2.5 Audio Description (Prerecorded) – Level AA
All prerecorded video content in synchronised media must have an audio description that conveys important visual details.

Key points:

• The description must be synchronised with the video and play during pauses in dialogue.
• If the video’s spoken content already describes all essential visuals, no separate audio description is required.
• Audio descriptions can be provided as a secondary audio track or integrated directly into the main soundtrack.

Why This Matters

Without audio descriptions, people who are blind or visually impaired miss out on crucial information that sighted viewers receive automatically.
Scenes, gestures, or text on the screen might carry meaning that isn’t spoken in dialogue.

With audio descriptions, users can hear what’s happening and experience the full context of the video just like everyone else.

What an Audio Description Includes

An effective audio description typically covers:

• Actions and gestures
• Facial expressions or emotional cues
• Scene changes and visual transitions
• On-screen text, titles, and graphics
• Any other important visual element not mentioned in the original audio

Example:
Instead of just hearing, “These photos were all taken at the Everglades,” the describer might add, “The teacher points to a map of Florida showing the Everglades region.”

When You Should Use It

You should add audio descriptions whenever your video:

• Contains information shown only visually (such as charts, diagrams, or on-screen text)
• Includes meaningful scenes, settings, or gestures not described in dialogue
• Is prerecorded and part of synchronised media, such as a course video, promotional clip, or documentary

If the visuals are essential for understanding, they must be described.

How to Add Audio Descriptions

There are a few ways to include audio descriptions:

1. Provide a separate audio track
   Use a second, user-selectable audio track with added narration.
   (Technique G78)
2. Create a version with integrated narration
   Mix the audio descriptions directly into the main soundtrack.
   (Technique G226)
3. Use extended audio description
   Add pauses in the video itself to insert longer narrations when needed.
   (Technique G8)
4. Use the <track> element for web videos
   Include audio description files using the HTML <track> element.
   (Advisory Technique H96)

Common Mistakes

Here are a few errors that cause accessibility failures:

• No description at all
  Users miss vital visual information.
• Descriptions not synchronised
  The narration doesn’t align with what’s happening on-screen.
• Missing pauses in dialogue
  Important visual moments are not described because there was no time allocated for them.
  (Failure F113)

Writing Good Audio Descriptions

When writing audio descriptions:

• Focus on what’s essential to understanding the video.
• Keep descriptions concise and natural.
• Avoid interpreting emotions unless clearly shown.
• Match the tone and pacing of the video.
• Make sure it fits naturally into pauses without overlapping dialogue.

Ask yourself:

• What’s visually happening right now?
• Is this information needed to follow the story or message?
• Would someone who cannot see understand this scene?

Wrapping Up

Audio descriptions make videos inclusive for everyone.
They ensure that people who are blind, have low vision, or have difficulty interpreting visuals can understand and enjoy video content.

By providing synchronised narration that explains important visuals, you meet WCAG Success Criterion 1.2.5 Audio Description (Prerecorded) and create a better, more accessible viewing experience.

Without descriptions: “I hear the dialogue but don’t know what’s happening.”
With descriptions: “I understand the full story.”

Adding audio descriptions isn’t just a compliance step; it’s about ensuring equal access to information and storytelling.