Auto B-Roll · Mac and iPhone
Add B-roll to a talking-head video automatically
Staring at the same face for a whole video is how attention drifts. Cutaways fix it, but finding, downloading and trimming stock for every line is a chore nobody has time for.
Auto B-Roll does the first pass for you, spaced across the whole video rather than dropped every few seconds, and each cutaway lands as a normal overlay you can swap, trim, move or delete.
- Mac and iPhone
- Free on every tier
Quick answer
To add B-roll automatically, run Zella's Auto B-Roll on Mac or iPhone: it reads your captions, picks the most visual keyword in each line on your device and places a cutaway near the words that mention it. With no key it generates designed keyword cards, with no account and no network: tap Add cutaways on iPhone, or click Add B-Roll on the Mac. Add a free Pexels key (or Pixabay on iPhone) if you want filmed stock footage instead; only the keyword is sent to search. It is free on every tier.
How to do it in Zella
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Step 1: Add captions first
Auto B-Roll works from your captions. Run Enable Captions on the Mac or add captions on iPhone, or ask the AI Assistant to add them.
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Step 2: Run it
On the Mac, click Add B-Roll. On iPhone, tap Add cutaways. You can also type add b-roll based on my captions to the Assistant.
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Step 3: Let it place the cutaways
Zella picks one visual keyword per caption line on the device and drops a card for it near that line. On the Mac each cutaway is full-frame, silent and about 4 seconds long, so your narration keeps playing.
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Step 4: Optional: use filmed stock footage
Paste a free Pexels key, or on iPhone a Pexels or Pixabay key under Use my own stock footage, and Zella fetches real clips instead. The key is stored in the Keychain on your device.
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Step 5: Tidy the first pass
Swap, trim, slide or delete any cutaway like any other overlay, so it lands on exactly the word you want.
Why do it this way
Works out of the box
No sign-up stands between you and the feature: the default cards are generated on the device and need no key and no network.
Spaced with intent
Cutaways are tied to the caption lines with the most visual words and spread across the video, so the result reads as edited rather than mechanical.
Only a keyword ever leaves
Keyword picking runs on the device. Even on the optional stock path, only the single search word is sent, never your video or your audio.
What you need
- macOS 14 Sonoma or later (Apple Silicon or Intel), or iPhone on iOS 18 or later
- Captions on the clip first, because Auto B-Roll reads them
- Optional, only for filmed stock footage: a free Pexels key (Pexels or Pixabay on iPhone) and an internet connection
- Free on every tier: no watermark, exports up to 2 minutes at 1080p
Questions
Do I need an API key for Auto B-Roll?
No. The default cutaway cards are generated on your device with no key and no account. A free Pexels key, or a Pixabay key on iPhone, is only needed if you want filmed stock footage.
Is my video uploaded to find b-roll?
No. Zella picks the keyword on your device. On the optional stock path, only that keyword is sent to the stock provider to search.
Why does it need captions first?
Auto B-Roll chooses its keywords from the caption text. Without captions there is nothing for it to read.
Is Auto B-Roll part of Zella Pro?
No. It is free on every tier on Mac and iPhone, like all of Zella's AI, including the AI Assistant.
Can I change a cutaway it picked?
Yes. Every cutaway is a normal overlay on the timeline, so you can replace it with your own footage, trim it, move it or delete it.
Related tools
Read the manual