B-roll footage is footage that is used to fill the time in between main shots. If the main footage is an interview the often the B-roll footage will be of the person working on something at their desk or people walking around the office, footage of city streets, an exterior of a building, close-ups of hands working etc. – this can be seen as filler footage to assist with the edit of the video and this footage can also be used to aid transitions or to emphasise the dialogue or key messages of someone being interviewed.