Captions
Captions are time-synchronized text representations of the spoken dialogue, sound effects, and other audio in a video, used by deaf and hard-of-hearing viewers and by anyone watching with sound off.
Detailed explanation
Closed captions can be turned on or off by the viewer; open captions are baked into the video. WCAG 2.1 SC 1.2.2 (Captions, Prerecorded) at Level A requires captions on all prerecorded audio in synchronized media. SC 1.2.4 at Level AA extends this to live audio.
Auto-generated captions from YouTube, Vimeo, or TikTok are typically 60–80% accurate and do not meet WCAG's "equivalent" bar. Production captions need a human review pass — at minimum to fix proper nouns, brand names, and product terminology.
How this applies to Shopify stores
Shopify's native video block does not auto-add captions. Theme video sections and product-page video need a `track kind="captions"` element pointing to a `.vtt` file. AccessComply flags videos missing a captions track.
Primary source: w3.org