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Audio description vs captions, subtitles and transcripts
Captions make audio accessible to people who cannot hear it. Audio description makes visuals accessible to people who cannot see them. Most accessible videos need both.
Side-by-side comparison
| Feature | Serves | What it contains | WCAG |
|---|---|---|---|
| Closed captions | Deaf and hard-of-hearing viewers | Speech and important sounds, can be turned on or off | 1.2.2 (A), 1.2.4 live (AA) |
| Open captions | Same | Captions burned into the picture, always visible | Can meet 1.2.2 |
| Subtitles | Viewers who do not speak the language | Translated dialogue, usually without sound cues | Not a substitute for captions |
| Audio description | Blind and low-vision viewers | Narration of important visual information | 1.2.3 (A), 1.2.5 (AA), 1.2.7 (AAA) |
| Transcript | Many users, including deafblind users | Text of speech, ideally with visual descriptions | Can meet 1.2.1 and 1.2.3, not 1.2.5 |
Do I need both?
To meet WCAG 2.1 Level AA, a prerecorded video with meaningful visuals generally needs captions and audio description. A transcript is a valuable extra and helps search engines, but it does not replace audio description at Level AA.
Described video vs audio description
They are the same thing. "Described video" is the common term in Canada; "audio description" is used in the U.S., U.K. and in WCAG.