Video & Multimedia Accessibility: Captions, Descriptions, Transcripts

Video represents 80% of internet traffic. If your videos aren't accessible, you're excluding millions of users and creating significant legal liability. Video accessibility isn't optional—it's essential for WCAG 2.1 compliance and user experience. This guide covers everything you need to know about making video and multimedia content accessible: captions, audio descriptions, transcripts, keyboard controls, and more.

Captions aren't just for deaf users. They benefit people watching in noisy environments, non-native speakers, and users who simply prefer reading along. Captions are required for WCAG 2.1 Level A compliance for pre-recorded video content. Open Captions are burned into the video and always visible. Closed Captions (CC) can be toggled on and off, allowing viewers to choose. Closed captions are almost always preferable because they give users control. Captions must be accurate, properly synchronized with audio, and include speaker identification. They should describe relevant sounds (door slams, background music changes) using brackets: [door creaks open]. Avoid spelling errors, poor timing, or missing dialogue. Poor captions are worse than no captions. Position captions in the lower third of the video, but avoid covering important visual content. Use readable fonts (sans-serif, 18-24pt minimum), high contrast backgrounds (dark background with white text), and adequate padding around text. Test captions at multiple screen sizes.

Audio descriptions (also called video descriptions or descriptive audio) provide narrated explanations of visual content for blind and low-vision users. For WCAG 2.1 Level AA compliance, pre-recorded video requires audio descriptions for important visual content. Describe important visual elements: character actions, scene changes, text on screen, graphs, demonstrations, and facial expressions. Avoid describing obvious elements (people talking) but do describe how they look or their setting. Audio descriptions should fill gaps between dialogue without overlapping. Write a script describing visual content in short, clear sentences. Record audio in a quiet environment with a clear voice. Edit descriptions into natural pauses in dialogue. Alternatively, provide a separate audio description track that viewers can enable. Many video platforms support this natively. YouTube automatically generates descriptions (not always accurate—review them). Professional services include 3Play Media, Rev, and Accessibility Solutions. For live events, trained describers provide real-time audio descriptions through a separate audio feed.

Transcripts are full text versions of video content. They benefit deaf users, people with processing disabilities, and users who prefer reading. Transcripts also improve SEO—search engines can't watch videos but can index transcript text. WCAG 2.1 requires transcripts for videos containing important information. Include all dialogue, speaker names, sound effects in brackets [laughter, applause], and descriptions of important visual content. Format transcripts with clear headings and sections. Make transcripts searchable and easy to navigate. Link transcripts prominently near the video player. The best transcripts are linked directly below or beside the video, not hidden behind a link that says "read transcript." When possible, make transcripts searchable (Ctrl+F) so users can find specific content. Include timestamps so users can jump to relevant sections. YouTube generates automatic transcripts (usually 80-90% accurate—always review). Rev, 3Play Media, and Descript provide professional transcription. For live content, CART (Communication Access Realtime Translation) services provide real-time transcripts.

Video players must be fully operable via keyboard. Users should be able to Tab to the player, then use standard keys: Space to play/pause, arrow keys to skip forward/backward, M to mute, and F for fullscreen. All controls must have visible focus indicators. Players need: play/pause, volume control, progress bar with current time, captions toggle, audio description toggle (if available), fullscreen button, and settings menu. Each control needs a label and keyboard shortcut. Screen readers should announce control names and states. When a user enters the video player, focus should move to the first control. When they exit, focus should move logically to the next page element. Ensure focus doesn't get trapped inside the player. Test with keyboard only—Tab, Shift+Tab, and arrow keys should work smoothly. YouTube and Vimeo have built-in accessibility features. Video.js is an open-source player with good accessibility. Kaltura, JW Player, and Brightcove offer enterprise solutions. Always test your chosen player for keyboard accessibility and screen reader compatibility before deploying.

Live events require real-time captions. CART (Communication Access Realtime Translation) providers employ trained stenographers who caption live content in real-time. Accuracy is typically 98%+ but requires experienced CART operators. This is expensive but essential for legal compliance and user experience. For live events, trained describers provide audio descriptions through a separate audio feed. Viewers can enable the description track on their device. This requires coordination with event organizers and audio infrastructure. If live captions aren't feasible, record the event and caption/describe it afterward. Within 7-14 days is a reasonable turnaround. Post the captioned/described version to your website and notify viewers that accessible versions are available. Test CART quality before the event. Ensure caption display is readable (size, positioning, background contrast). Test audio description audio level and clarity. Have backup CART operators in case primary operator has technical issues.

Podcasts are audio-only content that requires transcripts. Include show notes, speaker names, and timestamps. For best accessibility, provide transcripts alongside the podcast player. Platforms like Anchor and Transistor can generate automatic transcripts. Describe important audio elements that convey information. If your audio relies on music to convey emotion, don't—use clear language instead. If sound effects convey important information, provide visual or textual alternatives. Always provide transcripts for audio content. Link transcripts directly from the audio player. Make transcripts searchable. For long-form audio, break transcripts into sections with timestamps so users can jump to relevant content.

Animations can convey important information but may confuse screen reader users. Provide text alternatives. Avoid animations with more than 3 flashes per second (seizure risk). Respect prefers-reduced-motion settings. If animation is purely decorative, hide it from screen readers with aria-hidden="true". Interactive content (simulations, games, educational tools) must be keyboard accessible and screen reader compatible. Provide keyboard alternatives for mouse interactions. Include transcripts or text alternatives for important information. Test thoroughly with assistive technology. When embedding third-party content (YouTube videos, interactive maps), ensure the embed is accessible. Provide titles and descriptions. Make sure keyboard navigation works. If third-party content isn't accessible, provide an accessible alternative.

Captions for all pre-recorded video and audio. Audio descriptions for important visual content. Transcripts for audio-only content. Video player keyboard accessible. Accurate, well-timed captions. Audio descriptions for all important visual content. Searchable transcripts with timestamps. Full keyboard control of video player. Screen reader compatible controls. Sign language interpretation for important content. Multiple caption styles for different preferences. Audio description toggle (not forced). High-contrast captions. Clear player design. Accessible video landing pages with descriptions.