Stock footage
Every scene needs b-roll. VidNexus searches several stock libraries at once, ranks the results by how well they match the scene, picks the best ones, and cuts them to length. You can change the pick at every step.
The sources
VidNexus searches three free stock sources for each scene: Pexels, Pixabay and Coverr. The results are put together, duplicates are dropped, and the clips are ranked before the best ones are picked. If no clips turn up, it searches for photos instead.
Pexels (required)
Largest catalog, best coverage for common subjects (people, places, activities). Free, no credit needed. Cap: 200 requests an hour on the free tier, which is plenty for normal use.
Pixabay (recommended)
Second source. Better than Pexels for illustrations, animations, and abstract concepts. Free with API key.
Coverr (optional)
Curated cinematic footage: a smaller catalog, but higher quality per clip on average. Free, no credit needed. Ask for a key by emailing team@coverr.co.
Higgsfield (optional · ai)
Not stock: an optional hosted service that turns one picture into a 5 or 10 second cinematic shot with a camera move (push in, orbit, pan, tilt, crane and more). About $0.21 per 5 second clip, billed by Higgsfield. Find it under Cinematic shot when you click a scene in the editor. It is the only AI video feature in VidNexus. Nothing is generated on your computer.
To stop using a source, clear its API key in Settings > API keys. The other sources cover the gap; results just get thinner. You can also turn stock footage off for a brand kit or one video, under Footage sources.
Scene → search prompt
The narration text of a scene is often not a good search query. "The ineffable nature of the Roman collapse" won't match anything on Pexels. So the AI model turns each scene's narration into a concrete phrase you can search for.
Narration → search prompt example
Scene narration
"Rome's currency, the denarius, had lost 99% of its silver content over three centuries. Every emperor debased it a little further to fund a bigger army."
Generated search prompt
ancient roman coins silver denarius currency
This runs once per scene after the script is written. To change one, click a scene in the editor, edit Visual prompt in the inspector, then click Fresh search. Fresh search replaces all of that scene's clips.
Smart ranking
Stock sites mostly sort by keywords. They'll rank a clip whose title contains "rome" above a clip that shows a Roman coin but is titled "ancient currency". To do better, VidNexus uses an AI image model (CLIP) that compares what each clip looks like with what the scene is about.
How the ranking works
Put together results from every source that has a key (up to 12 clips).
Download each clip's thumbnail (just the small picture, not the clip).
Compare each thumbnail with the scene's visual prompt and narration.
Sort the clips by how well they match.
Keep the best 5 and play the top ones in the scene.
This runs on your graphics card when it can, and on the processor otherwise.
B-roll cycling
A long scene with one clip on loop is boring. So a scene can play several clips one after another.
A scene uses 1 to 4 clips, about 3.5 seconds each, depending on how long the scene is.
Ways to change the clips
Hover a clip under B-roll clips and click + to add it after the others.
Click a clip to use only that one.
Hover a playing clip and click × to take it out. The others stay.
The "N playing" label shows how many clips play in the scene: green for 1, violet for several, grey for 0 (the scene will be black).
Trimming and zoom
Stock clips are often 10 to 30 seconds long. Scenes are usually shorter, so VidNexus cuts each clip to fit.
For still shots and photos, a slow zoom makes the frame feel alive. In the inspector, under Zoom & pan, pick Static, Zoom in, Zoom out or Punch in.
Manual override
The automatic pick works well for most scenes, and poorly for a few. The editor gives you two ways to fix it.
1. Pick a different clip
Click a scene and look under B-roll clips in the inspector. It shows up to 5 clips, best match first. Click one to use only that clip.
2. Rewrite the visual prompt
No clips found? The prompt was too abstract. Edit Visual prompt in the inspector and click Fresh search.
Attribution
Pexels, Pixabay and Coverr clips are free to use in your videos, and no credit is needed. Each scene's source and credit is shown under Attribution in the inspector, if you want to credit creators anyway.
What's next
Motion graphics: Overlays that sit on top of the stock b-roll.
Render pipeline: How voice, footage, motion graphics and captions become the MP4.