A-roll footage is the main shot you want to focus on. A-roll shows the main subject of the scene while B-roll shots are supplemental footage that shows everything else. A story with simply A-roll footage might feel off-balance; this is why shooting B-roll is important.
The term for A-roll vs B-roll originated in the earliest days of Hollywood movie making, when principal footage was termed A-roll. An identical roll of film, the B-roll, or B-reel, was used for filler and transitional cuts.
B-roll footage, Broll or B roll is any supplemental video that considered to be secondary to your primary footage. B-roll can be gathered with a separate unit, acquired from stock footage, or obtained from any source other than your principal photography.
There are many ways to use B-roll footage. These include:
- Setting the tone
- Providing flexibility in the editing process
- Establishing characters or setting
- Breaking up monotony
- Covering up gaps or errors