In a traditional cut, A-roll is the interview or presenter; B-roll is the insert that covers a jump or illustrates a claim. The labels are editorial, not model names. A UGC ad often is all A-roll. A product demo is often all B-roll with a voiceover and no face.
Generating a talking presenter when the brief was product plates is inventing A-roll you did not ask for. Generating lifestyle B-roll when you needed the approved SKU still is throwing away the A you actually have. Picture-in-picture is one way to keep both once you have two files.
The B-roll glossary page is the insert. This page is the spine. UGC is the ad format that often wants A-roll from a creator rather than a studio host.
In practice
- Decide whether the spine is a person or a product before you pick a model.
- If the spine is a SKU still, do not generate a host to 'make it a video.'
- Cover A-roll with B-roll you actually own; a generated insert that contradicts the speaker is worse than a jump cut.
The mistake to avoid
Prompting one clip to be both the host and the product proof. That is not A-roll plus B-roll; it is one generate asked to be two shots.
Where you will run into it
- AI B-Roll Generator — No more generic stock. Every clip made for your script.
Related terms
B-roll
B-roll is the supporting footage cut over narration or an interview — everything on screen that is not the person doing the talking.
UGC
UGC is content made by an ordinary person — a customer, fan or creator — rather than by the brand itself, and it now covers everything from an unprompted review to paid creator work built to look exactly like one.
Picture-in-picture
Picture-in-picture is compositing a smaller video — usually a talking head or reaction — over a base clip, rather than generating a new clip that already contains both.
Voiceover
A voiceover is a spoken track laid under picture, rather than lipsync that drives a mouth or a caption track that visualises speech.
Hook rate
Hook rate is the share of people shown a video who are still watching a few seconds in — the number that grades the opening, not the edit behind it.
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