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.

In film, smaller MOS cameras, lacking sound circuitry, may be used for greater portability and ease of setup.

[2] In a docudrama project, B-roll may refer to dramatic re-enactment scenes staged by the producer and performed by actors, to be used as cutaway shots.

[6][7][8] Until the mid-1970s, news teams shot both main A-roll and secondary B-roll footage on 16 mm film.

The A-roll and B-roll scenes, shot at 24 frames per second, were converted to the television frame rate of 30 fps using a telecine system consisting of two film projectors, one showing the main A-roll footage and the other showing the B-roll.