Video, audio and motion: what accessibility asks

The short version

• Video with speech: correct captions (Level A). Our captions and transcripts guide shows how.
• Important things shown but not said: describe them in the narration, a transcript, or an audio description track (A and AA).
• Audio only, like a podcast: a transcript (Level A).
• Sound that starts by itself for more than three seconds: give a way to stop it, or don’t autoplay (Level A).
• Sliders, carousels and animations that move for more than five seconds: a pause button (Level A). Nothing should flash more than three times a second.

Which rules apply to which kind of media?

The W3C’s planning guide for audio and video, updated September 17, 2024, sorts the media rules by type. For a typical business site, these are the ones that matter:

The W3C notes that most organizations aim for Level AA, which includes everything at A.

What does each one mean in practice?

Captions

Captions are the spoken words and important sounds, timed to the video. The W3C’s page on prerecorded captions explains the rule. Automatic captions are a start, but names, places and trade terms often come out wrong, so correct them. Our captions and transcripts guide has the steps for YouTube and self-hosted video, so we won’t repeat them here.

Audio description

If the video shows something important that nobody says aloud, a blind viewer misses it. Think of a contractor pointing at a crack, or text on screen giving a phone number. The W3C’s page on audio description or a media alternative explains the options.

The simplest fix for a small business is to describe as you film. Say “This crack runs along the chimney flashing” instead of “See this?” Read out any phone number or web address you show. When the narration already covers every important visual, there’s little left to describe.

For videos where that’s not possible, a separate described version or a descriptive transcript works at Level A. Level AA asks for audio description itself.

Transcripts

A transcript is the text of everything said, plus important sounds. For a descriptive transcript, it also includes what’s shown. Put it on the same page as the video or link to it right beside it. For a podcast, a transcript is the Level A requirement.

Live video

Live video with sound needs live captions at Level AA. Many webinar and streaming tools offer automatic live captions. Check how accurate they are before you rely on them, and post a corrected recording afterwards.

What about autoplay, sliders and animation?

These rules catch more small business sites than video ones do.

• Sound that plays by itself. The W3C’s audio control rule (Level A) says audio that starts automatically and lasts more than three seconds needs a way to pause or stop it, or a separate volume control. The W3C notes that muting the computer doesn’t count. A background video with sound, or a welcome message that speaks on load, fails unless it has that control. Easiest fix: don’t autoplay sound.
• Moving content. The W3C’s pause, stop, hide rule (Level A) covers anything that moves, blinks or scrolls by itself for more than five seconds alongside other content, like a homepage slider, a scrolling news ticker or a looping background video. People need a way to pause, stop or hide it. Moving content pulls attention and makes reading hard for many people.
• Flashing. The W3C’s three flashes rule (Level A) says nothing should flash more than three times in any one second, unless it stays below set limits. Flashing can trigger seizures. Avoid strobe effects in video and animation.

Why does this matter?

People who are deaf or hard of hearing need captions. People who are blind need the visuals described. People with attention or reading difficulties need moving things to stop. And plenty of other people watch on a muted phone. DOJ’s web guidance names missing captions among the common barriers on business sites.

What are the common mistakes and edge cases?

• Uncorrected automatic captions, with wrong names and no punctuation.
• Text on screen nobody reads aloud, like a phone number at the end of an ad.
• A homepage slider with no pause button, or one that only pauses on mouse hover. Keyboard and touch users can’t hover.
• A background video with sound.
• Embedded social videos from Facebook or Instagram with no captions. Caption them before posting, or burn captions into the video file.
• Players you can’t use with a keyboard. Test the play and pause buttons with Tab and Enter. See how to test with a keyboard and a screen reader.
• Overlay text with low contrast, like white captions over a bright scene. See how to check color contrast.

What if this didn’t work?

• Your page builder’s slider has no pause button. Turn off autoplay, or swap the slider for a single strong image. That’s often better for speed and clarity too.
• Your video host won’t show captions. Upload a caption file, or host it on YouTube and embed it. Our guide on choosing YouTube, Vimeo or self-hosting compares the options.
• You can’t add audio description to an old video. Add a descriptive transcript now, and describe as you film next time.

How much does it cost, and how long does it take?

Correcting automatic captions takes roughly as long as the video, or a bit more. Describing as you film costs nothing extra. Turning off autoplay or adding a pause control is usually a small theme or settings change. Professional captioning and audio description services charge by the minute, and prices vary, so get quotes.

How does E-3 handle this?

When you send us a video to add, or ask us to change a slider or animation, a person at E-3 makes the change. That’s part of website care. Our captions and transcripts guide covers what we’d ask you to check in the captions.

Related questions

• How do I add captions and transcripts to my videos?
• How do I add a video to my website?
• How do I check and fix color contrast?
• Which WCAG level should I aim for?
• Back to the complete website accessibility guide

Sources

1. Planning audio and video media (W3C WAI, updated September 17, 2024)
2. Understanding SC 1.2.2: Captions (prerecorded) (W3C WAI)
3. Understanding SC 1.2.3: Audio description or media alternative (prerecorded) (W3C WAI)
4. Understanding SC 1.4.2: Audio control (W3C WAI)
5. Understanding SC 2.2.2: Pause, stop, hide (W3C WAI)
6. Understanding SC 2.3.1: Three flashes or below threshold (W3C WAI)
7. Guidance on web accessibility and the ADA (U.S. Department of Justice, March 18, 2022)