How can I caption a video that is intended for a Blackboard course?
You can add captions to a video in different ways. Some systems, like Panopto, and Echo360, provide ASR (automatic speech recognition).
You can find options for captioning videos for any use in the Digital Accessibility Committee website: http://accessweb.uic.edu/captioning-at-uic/
You can learn how to use some of those technologies for captioning at the ACCC Academic Multimedia Lab.