When you include videos on your website, they make your content richer and more engaging.
But for users who are blind or have low vision, the visual parts of a video, like actions, gestures, or scene changes, can be completely missed unless you provide a description.
Without an audio description or media alternative, these users only hear the dialogue or sounds, not the visuals that carry meaning.
That’s why every prerecorded video needs either an audio description or a full text alternative that explains the visual content.
What Are Audio Description And Media Alternative?
An audio description is an additional narration track that describes important visual elements in a video, such as actions, settings, or on-screen text, during pauses in the main audio.
A media alternative (also called a text alternative for time-based media) is a written version of everything in the video, both visual and spoken content, presented in the same sequence.
It reads like a detailed transcript, describing visuals, sounds, and dialogue so that the user can understand the full video without seeing it.
Example
With audio description:
“The teacher shows a chart comparing bird beak lengths. She points to the longest one.”
With media alternative (text version):
Scene opens in a classroom. The teacher holds a chart showing bird beak lengths. She points to the longest one.
Teacher: “Birds with longer beaks can reach food in deeper water.”
Why Does This Matter?
People who are blind or have low vision can’t perceive the visual parts of a video.
An audio description tells them what’s happening so they can follow along just like everyone else.
Without it, key information like who’s speaking, what’s on screen, or what actions are taking place might be lost entirely.
A media alternative ensures full accessibility for those who prefer or require text instead of audio or video.
When Should You Use It?
You should provide audio description or a media alternative for all prerecorded synchronised media, such as:
- Educational videos
- Tutorials and demonstrations
- Webinars or talks with on-screen visuals
- Marketing or explainer videos
If your video’s visuals are already fully explained in the audio (for example, a simple interview where speakers describe everything clearly), then no extra description is required.
How Do You Add It?
There are two ways to meet this requirement, both works at WCAG Level A.
1. Add Audio Description
Add a narration track that describes key visual details during natural pauses in the dialogue.
Example:
<video controls>
<source src="lesson.mp4" type="video/mp4">
<track kind="descriptions" src="lesson-descriptions.vtt" srclang="en" label="English descriptions">
</video>
2. Provide a Text Alternative
Offer a written version of everything shown and said in the video, like a detailed transcript or screenplay.
Example:
<a href="lesson-transcript.html">Read the full text alternative for this video</a>The transcript should include:
- Descriptions of visual actions
- On-screen text or graphics
- Dialogue and non-speech sounds (music, laughter, background noises)
- Any interactive cues (for example, “Press now to answer the question”)
Writing Good Audio Descriptions and Alternatives
When creating descriptions, focus on what’s important for understanding, not every tiny visual detail.
Ask yourself:
- What’s happening that the user needs to know?
- Who is speaking or acting?
- What changes on screen help explain the content?
Tips:
- Keep it concise and clear.
- Describe only meaningful visuals.
- Match the language and tone of the video.
- For transcripts, maintain the same order of scenes and dialogue.
Decorative or Redundant Visuals
If the visuals don’t add any new information, for example, a background pattern or animation that’s just decorative, you don’t need to describe it.
Focus only on visuals that convey meaning.
Success Criterion (1.2.3 – Audio Description or Media Alternative)
Requirement (Level A):
An alternative for time-based media or an audio description of the prerecorded video content is provided for synchronised media, except when the media is a media alternative for text and clearly labelled as such.
This means you must provide either an audio description or a text alternative for prerecorded videos with meaningful visuals.
Benefits
This helps:
- People who are blind or have low vision understand what’s happening on screen.
- Users in noisy environments or with limited bandwidth who prefer text.
- Anyone who learns better through reading than listening.
Wrapping Up
Audio descriptions and media alternatives make videos accessible for everyone, especially for users who can’t see what’s happening on screen.
Always include:
- An audio description for visual content that adds meaning.
- A text alternative when audio description isn’t possible or practical.
It’s a simple addition that ensures your videos communicate clearly to all users.
