B-Roll

B-roll gives you flexibility according to the video editing rules when editing because it is supplemental footage that makes a previously incongruent scene smooth.

B-roll can also provide more details to support the scene like in the news, wedding films, or interviews.

Say you were shooting footage of a person walking in a park and you wanted to shift into a new view of the subject. B-roll, like the image below in the park, can be inserted to make the transition easy on the eyes.