Captions (Prerecorded)

Understanding WCAG2.0

"Caption" does not discriminate only speaker's utterance contents like movie subtitles. (Synchronously) the information necessary for understanding the video, such as who is talking, what kind of sound effect sounded, and so forth. In other words, there is something like movie subtitles, 1.2.2 can not be achieved.

Incidentally, "closed caption" is a caption that can be switched between display and non-display, and "open caption" means a caption displayed as characters imaged in the movie (imagining a telop of a news program etc. ).

Principle Perceivable Information and user interface components must be presentable to users in ways they can perceive.
Guideline Time-based Media Provide alternatives for time-based media.
Criterion Captions (Prerecorded)
(1.2.2 A)
Captions are provided for all recorded audio content included in synchronized media (e.g. video with audio).

URL of Techniques for WCAG 2.0