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Introduction:
This article walks through best practices for creating descriptions for visual elements in recorded video presentations. These practices are designed to support equitable access to visual elements in instructional videos, recorded lectures, demonstrations, simulations, and multimedia learning materials. Educational videos and graphics are required to have audio descriptions (either in the main audio track or in an added audio description) to be fully accessible and compliant with WCAG 2.1 AA SC 1.2.5, as part of Title II standards.
In this article, you will walk through the process of creating descriptive audio for the visual elements presented in the sample Extended Audio Description view embedded below.
There are additional articles on Audio Descriptions:
Table of Contents:
Extended Audio Description Example
Audio description is an accessibility feature that provides spoken narration of important visual content in video or graphical multimedia. Audio descriptions help ensure that listeners who are blind or have low vision can access information that is presented visually but not conveyed through dialogue, narration, or other audio elements.
The video below walks through the basics of audio description and provides examples of visual slides that include appropriate extended descriptive tracks (Note: descriptive slides start at 1:22).
Creating Descriptive Text Options — Walkthrough
When creating video demonstrations and slide decks for visually impaired audience members, three distinct accessibility tools are used depending on how content is accessed:
Example One - Line Graph showing Annual Sales Growth
Note: Shown in Slide 3, at 1:22 in the video above.
Why It Is Needed
Line graphs communicate exact data points and trends over time. Without descriptions, visually impaired audience members lose access to underlying numbers and context.
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Option A: Adding Alt Text (For Static Slide Decks)
How to Add: Right-click the line graph image in PowerPoint/Google Slides, select "View Alt Text", and enter concise, non-sentence metadata.
- Insufficient Example: Sales graph. Line goes up to $11.8M. (Lacks axis details, interval structure, and baseline numbers. Key takeaway: steady annual growth with acceleration in later years.)
- Appropriate Example: Line graph titled "Annual Sales Growth, 2020–2025". Horizontal axis: years 2020 to 2025. Vertical axis: revenue in millions of dollars, 0 to 14 in 2-million intervals. Data values: 2020: $4.1M; 2021: $5.0M; 2022: $6.2M; 2023: $7.8M; 2024: $9.5M; 2025: $11.8M (peak). Key takeaway: steady annual growth with acceleration in later years.
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Option B: Web.VTT file (For Extended Audio Descriptions)
How to Add: Include a timed 1-second pause cue in your VTT file after introducing Slide 3 so the video player pauses to announce the visual data. You can download the .VTT file used for this presentation as an example of this type of file formatting.
Appropriate VTT Code Snippet:
00:01:29.400 --> 00:01:30.400 The slide is split into two sections: a line graph on the left and a summary card on the right. The line graph is titled "Annual Sales Growth, 2020–2025". The vertical axis represents Revenue in millions of dollars ranging from 0 to 14, marked at 2-million-dollar intervals. The horizontal axis plots the years from 2020 to 2025. The trend line shows a continuous upward trajectory, starting at 4.1 million dollars in 2020, rising steadily to 5 million in 2021, 6.2 million in 2022, 7.8 million in 2023, 9.5 million in 2024, and peaking at 11.8 million dollars in 2025.
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Option C: Integrated Description (For Presenter Script / Video Narration)
How to Add: Fully address the chart setup and coordinates in your main script, verbalizing all visual elements during the lecture.
- Insufficient Example: "As you can see on Slide 3, our revenue increased over time as listed on the right." (Assumes visual sight; omits data.)
- Appropriate Example: "Moving to Slide 3, 'Annual Sales Growth, 2020–2025', we have a line graph on the left tracking revenue in millions from 0 to 14. Starting at $4.1M in 2020, revenue rises to $5.0M in 2021, $6.2M in 2022, $7.8M in 2023, $9.5M in 2024, and peaks at $11.8M in 2025."
Example Two — Bar Chart Showing Customer Satisfaction Survey Results
Note: Shown in Slide 4, at 1:56 in the video above.
Why It Is Needed
Bar charts display categorical distributions and relative proportions. Visually impaired audience members need to hear both the ordered categories along the axis and the exact percentage values assigned to each bar.
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Option A: Adding Alt Text (For Static Slide Decks)
How to Add: Right-click the bar chart graphic in PowerPoint or Google Slides, select "View Alt Text", and enter structured metadata.
- Insufficient Example: Bar chart showing customer survey results where most people are satisfied. (Omits category list, percentage intervals, and individual data points.)
- Appropriate Example: Bar chart titled "Customer Satisfaction Survey Results". Horizontal axis: categories from left to right: Very Satisfied, Satisfied, Neutral, Dissatisfied. Vertical axis: satisfaction percentage, 0% to 70% in 10% intervals. Data values: Very Satisfied: 65%; Satisfied: 20%; Neutral: 10%; Dissatisfied: 5%. Key takeaway: positive ratings dominate, with Very Satisfied leading by a wide margin.
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Option B: WebVTT File (For Extended Audio Descriptions)
How to Add: Include a timed 1-second pause cue in your VTT file after introducing Slide 4, allowing the video player to freeze and announce the chart layout.
Appropriate VTT Code Snippet:
00:02:03.000 --> 00:02:04.000
The slide is split into two sections: a vertical bar chart on the left and a summary card on the right. The chart is titled "Customer Satisfaction Survey Results". The vertical axis represents the satisfaction percentage from 0% to 70%, marked at 10% intervals. The horizontal axis lists four categories from left to right. The bars show: "Very Satisfied" at 65%, "Satisfied" at 20%, "Neutral" at 10%, and "Dissatisfied" at 5%.
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Option C: Integrated Description (For Presenter Script / Video Narration)
How to Add: Verbally embed the category progression and percentages into your main presentation script.
- Insufficient Example: "On Slide 4, our survey results show that a majority of customers are happy with us, as listed on the takeaway card." (Skips category breakdown and bar percentages.)
- Appropriate Example: "Slide 4 displays our 'Customer Satisfaction Survey Results' bar chart. Across the bottom axis, four categories are measured against a percentage scale from 0% to 70%. On the far left, 'Very Satisfied' leads at 65%, followed by 'Satisfied' at 20%, 'Neutral' at 10%, and 'Dissatisfied' at 5% on the far right. Positive feedback accounts for 85% of total responses."
Example Three - Data Table showing Enrollment by Program and Year
Note: Shown in Slide 5, at 2:30 in the video above.
Why It Is Needed
Data tables present relational matrix information across rows and columns. Visually impaired audience members need explicit mapping of category headers to numerical values.
Enrollment by Program and Year
|
Program
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2020
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2022
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2024
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2025
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Undergraduate
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450
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540
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610
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675
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Graduate
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120
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158
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190
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224
|
|
Continuing Ed.
|
75
|
92
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101
|
118
|
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Option A: Adding Alt Text (For Static Slide Decks)
How to Add: Add to flattened table in slides to preserve full data set accessibility.
- Insufficient Example: Table showing enrollment numbers for programs. (Does not explain all cell values and program rows.)
- Appropriate Example: Data table titled "Enrollment by Program and Year". Columns: Program, 2020, 2022, 2024, 2025. Rows: Undergraduate: 450, 540, 610, 675; Graduate: 120, 158, 190, 224; Continuing Ed.: 75, 92, 101, 118. Key takeaway: enrollment increased across all three academic programs, led by Undergraduate.
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Option B: WebVTT File (For Extended Audio Descriptions)
How to Add: Include a timed 1-second pause cue in your VTT file after introducing Slide 5, allowing the video player to freeze and announce the table information.
Appropriate VTT Code Snippet:
00:02:36.000 --> 00:02:37.000
The slide is split into two sections: a data table on the left and a vertical list of five key takeaway bullet points on the right. The table is titled "Enrollment by Program and Year" and contains four columns for the years 2020, 2022, 2024, and 2025 across three academic program rows. Undergraduate enrollment grows from 450 in 2020, to 540 in 2022, 610 in 2024, and 675 in 2025. Graduate enrollment grows from 120 in 2020, to 158 in 2022, 190 in 2024, and 224 in 2025. Continuing Education enrollment expands from 75 in 2020, to 92 in 2022, 101 in 2024, and 118 in 2025.
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Option C: Integrated Description (For Presenter Script / Video Narration)
How to Add: Articulate row headings and numerical shifts chronologically.
- Insufficient Example: "On Slide 5, we have a table showing enrollment growth across all our academic programs." (Skips cell specifics.)
- Appropriate Example: "Slide 5 features an enrollment table covering four years. Reading across programs: Undergraduate grew from 450 in 2020 to 675 in 2025. Graduate grew from 120 to 224, and Continuing Education expanded from 75 to 118 over the same period."
Example Four — Complex Illustration Showing an Emergency Evacuation
Note: Shown in Slide 6, at 3:04 in the video above.
Why It Is Needed
Complex isometric graphics contain rich spatial interactions, environmental hazards, and safety signage. Without descriptions, visually impaired audience members cannot map the visual drawing to the safety principles discussed.
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Option A: Adding Alt Text (For Static Slide Decks)
How to Add: Add concise descriptions directly to the main graphic container in your slides.
- Insufficient Example: Illustration of an emergency exit drill with people running. (Vague; omits firefighters, smoke, map, and exit signs.)
- Appropriate Example: Isometric illustration titled "Communicating Information Through Visual Content". Hallway filled with dark smoke on far left, with two firefighters in gear carrying axes moving toward hazard. Three occupants run past wall-mounted evacuation map toward open double doors marked "EMERGENCY EXIT". Two safety workers guide evacuees—one pointing direction and one holding a megaphone at the exit door. Visual content: emergency evacuation procedure depicting occupants following designated routes and staff instructions.
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Option B: WebVTT File (For Extended Audio Descriptions)
How to Add: Include a timed 1-second pause cue in your VTT file after introducing Slide 6, allowing the video player to freeze and describe the complex image.
Appropriate VTT Code Snippet:
00:03:13.700 --> 00:03:14.700
The slide is split into two sections: a sample emergency evacuation illustration on the left and a card listing five key safety steps on the right. The illustration demonstrates an evacuation in a gray hallway. On the far left, dense gray smoke clouds billow inward. Two firefighters wearing yellow helmets, protective suits, oxygen tanks, and masks march toward the smoke carrying axes. Near the center, a third firefighter points directing people toward the right. Three individuals (a woman in a red shirt, a man in a light blue sweater, and a woman in a blue tank top) are running away from the smoke past an emergency evacuation map toward an open double door on the right. Above the door is a white sign with bold red letters reading "EMERGENCY EXIT". A fourth firefighter stands by the exit doors speaking into a megaphone and waving his arm to guide people out.
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Option C: Integrated Description (For Presenter Script / Video Narration)
How to Add: Verbally paint a mental picture of the hallway layout while delivering the lesson.
- Insufficient Example: "To wrap up, Slide 6 shows a drawing of an emergency drill. Make sure to follow the five steps on the card." (Ignores the illustration completely.)
- Appropriate Example: "Slide 6 features an isometric drawing of an emergency evacuation. On the far left, dark smoke fills the hallway as two firefighters in gear head toward it with axes. Three occupants run past a wall evacuation map toward open double doors under a red 'EMERGENCY EXIT' sign. Near the door, two safety workers guide traffic—one pointing the direction and another holding a megaphone."