What is B-roll, and why does every good video have it?

B-roll is the supplementary footage you cut over your main shot to illustrate a point, add motion, and hold attention. If the camera pointed at you talking is the spine of the video, B-roll is everything you cut to in between — a screen recording of your product, a quick stock shot, an animated diagram, a photo pulled from the web. It carries the story when your face alone would get stale.

Here's the catch for founders: you know the talking-head clip on its own feels flat next to what's on the feed, but sourcing, trimming, and placing B-roll is exactly the kind of fiddly editing work that eats an afternoon. That's the editing tax — the unwritten rule that to look good you have to become a part-time editor.

We built OpenNolan because we're builders too, and we'd rather ship product than babysit a timeline. This page is the honest version of what B-roll is and how to use it well — and where an AI agent can do the sourcing and placing for you so you don't have to.

A-roll vs B-roll: the two layers of any video

A-roll is your primary footage — the main thing the video is about. For a founder that's usually you on camera explaining the product, or a screen demo you narrate. It carries the words and the throughline.

B-roll is the secondary footage layered over or cut between A-roll. It doesn't drive the narration; it supports it. When you say "users were dropping off at checkout," the B-roll is the screen recording of that checkout flow. The audio keeps running underneath, so the cut never breaks your point — it just gives the viewer something to look at while you make it.

• A-roll = the main shot that carries the message
• B-roll = cutaways that illustrate and add motion
• B-roll usually plays under continuous A-roll audio
• Good videos alternate between the two constantly

Why B-roll holds attention

Don't tell them it's good. Cut to two seconds of it being good.

Short-form lives and dies on the first second and every second after. A static talking head gives the eye nothing new, and attention leaks. Every cut to B-roll is a small visual reset — the same reason fast cuts every one to three seconds keep people watching. New frame, renewed attention.

B-roll also does work words can't. Telling someone your dashboard is clean is weak; showing two seconds of the dashboard is proof. That's the "show receipts" rule of the short-form playbook — screenshots, stats, and real footage make a claim land and convert far better than narration alone.

Where founders actually get B-roll

You don't need a film crew. There are four practical sources, and most reels mix all of them:

• Screen recordings — your product, dashboard, terminal, or browser in action. The highest-converting B-roll for builders, because it's real proof.
• Stock footage — generic shots for mood or context (a city, hands typing, a coffee). Fast, but can feel generic if overused.
• AI-generated B-roll — short clips generated to match your script when no real footage exists for the idea.
• Images from the web — logos, screenshots, charts, photos dropped in and held on screen with a little motion.

How to cut B-roll in (the manual way)

Done by hand, the loop looks like this: find the moment in your A-roll where a claim needs support, source a clip for it, drop it on a track above your main footage, trim it to roughly two seconds, and let the A-roll audio keep playing underneath. Repeat for every claim. Then nudge each cut so the B-roll lands on the word it illustrates, not a beat early or late.

It's not hard. It's just slow, and there's a lot of it. A two-minute reel can need a dozen cutaways, and every re-trim means re-watching. This is the part of editing that quietly turns into your whole evening.

How OpenNolan pulls and places B-roll for you

OpenNolan is a Mac app where an AI agent makes the whole vertical reel from your raw clips. B-roll is a big part of what it handles: it reads your script, finds the moments that need support, and pulls supporting images and B-roll from the web — plus AI-generated B-roll video and screenshot proof with auto-highlight when that fits better. Then it places each cutaway on the timeline, timed to the line it illustrates.

You stay the editor. Every placement lands on a real timeline, so you can swap a clip, retrim a cutaway, or move it a beat — and because OpenNolan renders once and keeps edits cheap, those tweaks preview instantly without re-rendering the whole video. See how the agent builds a Reel end to end, or browse everything the agent can do.

It's bring-your-own-key and open source: you add your own AI provider key and pay providers directly, with no subscription and no markup. The app isn't released yet — this is the waitlist — but B-roll automation is core to what it does.

• Agent finds moments that need a cutaway
• Pulls B-roll and images from the web, or generates them
• Places each clip timed to the line it supports
• You retrim and swap on a real timeline, instantly

Frequently asked questions