WCAG SC 1.2.2 Captions (Prerecorded) – Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
WCAG SC 1.2.3 Audio Description or Media Alternative (Prerecorded) – An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
Section 508 503.4.1 Caption Controls – Where user controls are provided for volume adjustment, ICT shall provide user controls for the selection of captions at the same menu level as the user controls for volume or program selection.
Section 508 503.4.2 Audio Description Controls – Where user controls are provided for program selection, ICT shall provide user controls for the selection of audio descriptions at the same menu level as the user controls for volume or program selection.