| name | wcag-av-requirements |
| description | Reference for WCAG 2.1 AA audio/video requirements under ADA Title II. Use when the user asks about captions, audio descriptions, video accessibility, live vs prerecorded video rules, sound effects in captions, audio-only or video-only content, embedded YouTube/Vimeo/Panopto videos, or "how do I make a video ADA compliant". Grounded in the UW eScience ADA Title II compliance notes. |
WCAG 2.1 AA Audio/Video Requirements
Apply these rules when reviewing or authoring content that embeds, links, or references audio or video media. The most important distinction is live vs. prerecorded. Grounded in the wcag-title-ii-notes skill.
Key principle: embedded and linked both count
From the compliance notes: these requirements apply even to videos embedded in the site or linked from the site. A YouTube link is no different from a <video> tag for compliance purposes.
The live vs. prerecorded table
| Requirement | Live | Prerecorded |
|---|
| Captions [1.2.2, 1.2.4] | Required — AI/algorithmic OK | Required — must be human-checked |
| Audio description [1.2.5, 1.2.9] | Not required at AA | Required |
| Text alternative for audio-only or video-only [1.2.1] | — | Required |
| Non-speech audio described in captions | Yes | Yes |
AI captions are acceptable for live video, not for prerecorded. This is the single most common mistake — uploading a Zoom recording with auto-generated captions is not compliant. A human must review them.
Captions [WCAG 1.2.2, 1.2.4]
- All video content requires captions.
- Non-speech audio must be described:
[bird call], [door slams], [applause].
- For prerecorded videos, captions must be human-reviewed even if they started as auto-generated.
- Captions in a
<track kind="captions" srclang="en"> element are the standard HTML approach. For embedded YouTube/Vimeo, verify captions exist inside the source platform.
Audio descriptions [WCAG 1.2.5]
Audio descriptions are spoken narration of visually important content that is not conveyed through dialog. Required for prerecorded video.
- For recorded talks: visual information (slides, graphs, demonstrations) must be described out loud. If the speaker already describes them in dialog, that counts.
- The practical rule from the notes: fill existing pauses in dialog with description of relevant visuals. If every pause is already filled, adding more is not required [WCAG 2.1 Technique F113].
- Audio descriptions can be added via dubbing after the fact.
- Live talks do not require audio descriptions at AA level [WCAG 1.2.9].
Audio-only and video-only content [WCAG 1.2.1]
- Audio-only (podcasts, recorded interviews): provide an equivalent text transcript.
- Video-only (silent demos, animated diagrams): provide an equivalent text description or audio description.
Sound effects and non-speech audio
Sound that carries meaning — a bird call played in a lecture, a warning chime, applause — must be described in the captions. This is part of [WCAG 1.2.2], not a separate rule.
Conforming alternate versions (CAVs)
If you cannot make the primary version compliant, you may provide a separate conforming version and link to it prominently. This is allowed by WCAG 2.1 but has strict labeling and access requirements. See the WCAG 2.1 CAV documentation. In practice: it is usually simpler to fix the original than to maintain a CAV.
Applicable exceptions
Some A/V content may qualify for an exception (see the wcag-exceptions skill):
- Archived content — if all four archive criteria are met.
- Preexisting social media posts — posts before the compliance date (April 24, 2026) are typically exempt.
Even when exempt, an accessible version must be provided on request.
Review checklist
When reviewing A/V content, answer:
- Is it live or prerecorded? (Recorded lectures = prerecorded.)
- Does it have captions? Are they human-reviewed (for prerecorded)?
- Does it have audio descriptions, or does the dialog already cover the visuals? (Prerecorded only.)
- Are non-speech sounds that carry meaning described in captions?
- For audio-only or video-only: is there a text alternative?
- Does any exception clearly apply?
What cannot be checked from source code
- Whether captions are accurate or human-reviewed.
- Whether audio descriptions are present inside the video.
- Whether the video platform exposes captions to the embedded player.
These require a human to watch the video or ask the content owner. The av-compliance-reviewer agent will flag these explicitly rather than give a false pass.
