Accessible media
An accessible video or podcast provides alternatives for each sensory channel: captions and transcripts for audio, audio description for visuals, and keyboard-usable controls.
The key rules
- Transcript: full text for audio and video.
- Captions: synchronised, in WebVTT format.
- Audio description: describes important visual elements.
- Controls: play, pause, volume, captions and audio description operable by keyboard, at the same level as playback.
- No autoplay sound longer than three seconds without a control (RGAA 4.10).
Code example
<video controls preload="metadata" width="640">
<source src="demo.mp4" type="video/mp4">
<track kind="captions" src="demo.en.vtt" srclang="en" label="English" default>
</video>
<p><a href="demo-transcript.html">Read the transcript</a></p>How to test
Play the video without a mouse, enable captions, mute the sound and check the information remains understandable. RGAA criteria: 4.1, 4.3, 4.10. Checklist: WebAIM Captions.
Frequently asked questions
Captions or transcript?
Both are complementary: captions follow the video, while a transcript also serves deafblind people and braille readers.
Is audio description needed for every video?
It is needed when visual information isn’t conveyed by the soundtrack; otherwise an enriched transcript may suffice depending on the criterion.