This video was created by the Digital Accessibility Program at UC Berkeley. It provides an introduction to captions and captioning requirements.
Links in slideshow:
3Play Media
https://go.3playmedia.com/custom-uc
Aberdeen Services
https://aberdeen.io/abercap/
Digital Accessibility Program - Accessibility Vendors
https://dap.berkeley.edu/accessibility-vendors
Digital Accessibility Program - Captions
https://dap.berkeley.edu/learn/concepts/captions
DCMP - Captioning Key
https://dcmp.org/learn/captioningkey
WCAG 2.1 - Success Criteria for Pre-Recorded Audio
https://www.w3.org/WAI/WCAG21/Understanding/captions-prerecorded.html