Subtitles & Video Accessibility
Video accessibility means making the spoken content of videos available through synchronised subtitles and, ideally, transcripts, so that deaf and hard-of-hearing users, or anyone watching without sound, can follow along — required by WCAG success criterion 1.2.2 (captions for pre-recorded video).
In practice
Automatically generated subtitles, from YouTube for example, are a reasonable starting point but should always be corrected by hand, because errors in names or technical terms undermine both comprehension and accessibility. An additional transcript does not only help screen reader users; it also makes video content findable through ordinary text search.