The supplemental footage used to visually support your A-ROLL.
When a television reporter appears in front of the camera to narrate part of a story – most often at the beginning to set up the story, in the middle as a transition or if there is no good b-roll to cover voiceover, or at the very end.
Source: Berkeley Advanced Media Institute
Narration and/or voiceover (VO), scene reconstructions, archival footage, nats (natural sound), b-roll, images, research, lengthy interviews, soundbites.
The story of one person, has voiceover (VO), b-roll, pictures, nats (natural sound), interviews of family members or peers of that one person.
Video stories about newsworthy issues and topics, factual information, balanced reporting, research, voice overs, soundbites, b-roll footage, infographics, reporter standup, nats (natural sound bites).
A recording of something going on (versus an interview).
Note: Think b-roll but for audio.