B-roll
SUPPLEMENTAL OR ALTERNATE FOOTAGE INTERCUT WITH THE MAIN SHOT IN AN INTERVIEW OR DOCUMENTARY
B roll; B Roll; B-roll footage; B reel; B footage; A/B roll
In film and television production, B-roll, B roll, B-reel or B reel is supplemental or alternative footage intercut with the main shot. The term A-roll, referring to main footage, has fallen out of use.