The Captioned Media accommodation applies to any media that is pre-recorded and played during a lecture, posted on a course website, or otherwise included in the course. For instance, if you have a folder of films or videos of interest on your bCourses site, those should be available in captioned formats.
If you post recordings of lectures, office hours, discussions, et cetera, those all should include captions, even if a Realtime Captioner was present during the live session.