B-Cam
A second camera, used in addition to the main camera. It gives the editor a different angle to cut to when editing a video.
B-Roll
The additional or supplemental footage captured, which is intercut with the main footage. It typically is used to support or add depth and/or context to the scenes by showing the environment, background action, or other scene embellishments. Ambient or natural sound is also recorded simultaneously. the term B-roll comes from the initial days of film when there was an “A” roll, which was all the speaking parts, and then the “B” roll which covered the action part of the film.
