Up until this past week I really only thought of B-roll (the non-subject matter footage in a video) one way. It was a filler meant to add depth-- through contrasting visuals or supportive ones-- to the main footage. It was a moving snapshot: the fidgeting hands of a speaker, the cut-away to what they're describing. All of these are shot one way... as snapshots.
But in working on my current project, a promotional video for a local company, I realized that my footage needed to be much more. It needed to tell a story, too. To do so, I needed the footage to follow basic shot format: a wide establishing shot followed by close-ups and points of view. The sequence of shots needed to have the same continuity; I couldn't jump from an establishing shot to a close-up of an entirely different moment. It needed to cut on the action. The narration was in support of the b-roll, not vice-versa.
Not all B-roll requires this level of structure; often times, the simple "snapshot" does exactly what it's supposed to. But now I'm on the lookout for times when the b-roll is the narrative, rather than the support.