To assist with compliance with WCAG 2.0 Level A/AA and to be fully accessible to the maximum number of users, web multimedia should include BOTH synchronized captions and a descriptive transcript.

Legislation

Ontario Regulation 191/11, section 14:

By January 1, 2014, new internet websites and web content on those sites must conform with WCAG 2.0 Level A.
As of January 1, 2021, all internet websites and web content must conform with WCAG 2.0 Level AA, other than, success criteria 1.2.4 Captions (Live), and success criteria 1.2.5 Audio Descriptions (Pre-recorded).
WCAG 2.0 Guideline 1.2.1 – “An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.”

WCAG 2.0 Guideline 1.2.2 – “Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labelled as such.”

McMaster online video policy specifies that every non-text element posted on the web—including audio and video files—must have a text equivalent. Adding captions to video is very straightforward in Kaltura MediaSpace. Instructions are located here.

Caption vendors we recommend: www.rev.com