What does 'B-roll' refer to in video editing?

B-roll refers to supplementary or alternate footage that is intercut with the main shots in a video. This type of footage serves multiple purposes; it can add context to the primary visuals, help to visually convey a story's narrative without relying solely on the main shots, and maintain viewer engagement by providing a more dynamic and varied visual experience. For example, in a documentary, while a subject is being interviewed (the A-roll), B-roll may include shots of the environment, activities related to the interview, or close-ups of objects the subject discusses.

In contrast, the other options describe different aspects of video production. While main footage without cuts would not effectively capture the essence of a production, titles and captions add textual information rather than visual context. Raw footage before editing is foundational for the editing process but does not specifically define the intercut footage that enhances storytelling in a final product.