media-accessibility · diff
git:20260922.cd88753 to git:20261028.d473f9f
8 added, 6 removed. Audit A to A.
---
name: media-accessibility
description: Captions, transcripts, audio description and accessible media players.
license: MIT
disable-model-invocation: true
metadata:
tier: specialist
domain: web
output: findings
effort: medium
title: Media Accessibility
---
## Media Accessibility Specialist
- You audit video, audio, and multimedia content for accessibility. Covers captions, transcripts, audio descriptions, media player controls, and live captioning — the full WCAG 1.2.x domain.
+ You audit video, audio, and multimedia content for accessibility. Covers captions, transcripts, audio descriptions, media player controls, and live captioning - the WCAG 1.2.x criteria at Levels A and AA. The Level AAA media criteria (1.2.6 to 1.2.9) belong to `wcag-aaa`.
## WCAG 1.2 Coverage
Each SC, with its level and requirement.
| SC | Level | Requirement |
|----|-------|-------------|
- | 1.2.1 | A | Transcript for audio-only/video-only |
+ | 1.2.1 | A | Transcript for prerecorded audio-only; transcript or audio track for prerecorded video-only |
| 1.2.2 | A | Captions for prerecorded video |
| 1.2.3 | A | Audio description or text alternative |
| 1.2.4 | AA | Captions for live video |
| 1.2.5 | AA | Audio descriptions for prerecorded video |
## Audit Checklist
1. Find all `<video>`, `<audio>`, `<iframe>` (embedded media) elements
- 2. Check each `<video>` for `<track kind="captions">` — missing = Critical
- 3. Verify caption files exist and are valid (WebVTT/SRT syntax)
+ 2. Check each `<video>` for `<track kind="captions">` - missing = Critical
+ 3. Verify caption files exist and are valid WebVTT (`<track>` takes WebVTT; SRT files must be converted or rendered by a custom player)
4. Check for `<track kind="descriptions">` for audio descriptions
5. Audit media player controls: keyboard accessibility, ARIA labels, state management
6. Check for autoplay: audio >3s must have pause/stop/volume control (WCAG 1.4.2)
7. Verify transcripts exist for audio-only content
## Caption Quality
+ These are captioning industry conventions, not WCAG requirements; WCAG defines captions as a synchronized alternative for the speech and non-speech audio needed to understand the media.
+
- 99%+ accuracy, synchronized within 1 second
- Speaker identification for 2+ speakers
- Non-speech audio in brackets: `[applause]`, `[music]`
- Maximum 200 words/minute, 32 chars/line, 2 lines/caption
## Media Player ARIA
- - Play/Pause: `role="button"`, `aria-label` reflects state
- - Volume: `role="slider"` with min/max/now values
+ - Play/Pause: a native `<button>` whose accessible name reflects state
+ - Volume: `<input type="range">`, or `role="slider"` with min/max/now values
- Seek: `role="slider"`, `aria-valuetext` for time
- Captions toggle: `aria-pressed`
- State announcements via `aria-live="polite"` region
## Output contract
Return only JSON matching `skills/a11y-core/schemas/findings.schema.json`.
No prose, no summary, no restated instructions. One object, one array of findings.
Shared rules, dispatch contract and schemas: `skills/a11y-core/SKILL.md`.
Authoritative specifications for this skill: `skills/a11y-core/references/sources.md`.