video-asset-sources

Find B-roll, stock footage, music, sound effects, motion blocks, lower thirds, transitions, fonts, icons, logos, LUTs and HDRIs that an AI agent can really fetch and legally put in a video. A decision procedure over 97 databases, each tested on 2026-11-03: which ones answer an agent at all, which query works, which license holds, and when to generate instead. Includes 37 tested no-key queries, the traps (easy APIs you cannot use commercially, popular lists that break a license), and a credits file for every asset. Use for "find b-roll", "stock footage for this", "royalty free music", "free sound effects", "whoosh sound", "free video assets", "pexels api", "freesound", "which database should I use", "can I use this clip commercially", or whenever an edit needs a file it does not have. Not for references to study rather than use (find-references) or for the edit itself (edit-footage-with-code).

Of 97 databases we tested, 14 have no route an agent can use and 7 more need a login. Several of the most recommended ones fail in ways that are not visible: the download works and the license does not. So route before you search, and record the license of every file.

Rules

1. Route first. If a page says "Just a moment", "Attention Required" or "Security Checkpoint", stop. Do not retry, change tactics or look for a scraper. Use the next source.
2. A file that downloads is not a licensed file. A premium clip's 1080p URL answered 200 with no login.
3. License gate. Accept: CC0, public domain, CC BY with a credit line, the Pexels, Pixabay, Mixkit Free and Coverr licenses, a paid plan the person holds. Reject: anything with NC, ND or SA, Sampling+, RemArc, Mixkit Restricted, and anything with no license signal. Never guess a license.
4. Record every asset: python3 <skill>/scripts/record_asset.py --file assets/whoosh.mp3 --source-url <url> --license CC0 --license-url <url>. Paste the credits into the video's description when the license wants one.
5. Reference libraries are for study. Their frames never go in the output.
6. Stop after 2 failed queries per source. Searching longer costs more than generating. Do not place a loosely related clip because it was available.
7. You cannot hear. Check placed audio with a tool or a person. Old library recordings can open with a spoken slate ("Line FX 5 take 1!", per @xiaohuaxi28). Trust no filename.
8. Take only what the edit uses. Pixabay's docs forbid "systematic mass downloads", and most sites expect the same.

Timeouts: 15 s for most APIs. 40 s for Openverse, then move on: 13 of 19 timed searches failed even at 40-60 s.

What to use for what

Need	First	Then	Generate when
Generic B-roll	Pexels API with a key. No key: Mixkit, then Coverr	Pixabay API	The shot names a product, person or place, or 2 queries found nothing matching the line
Real-world or archival	Wikimedia Commons. Space and Earth: NASA	Internet Archive, license filter on	Never for a claim of fact. Label a reconstruction, or use a graphic
Music bed	A subscription the person holds (Epidemic Sound MCP). No plan: Incompetech if a credit is fine, Mixkit if not	Generated bed: varg mureka_9_5	Exact length and structure, or no credit line possible
Sound effect	Freesound filtered to CC0	Mixkit, Kenney for UI ticks, HyperFrames' bundled files	A signature sound (ElevenLabs), or a hit that must land on a frame across re-renders
Motion block, lower third, transition	HTML project: HyperFrames registry. Remotion: video-shotcraft, remotion-bits, @remotion/transitions	LottieFiles, Herk Edit Kit's draft cards, varg How-To	It must carry your data or brand. Write it, seek-safe. Before any transition: would a hard cut work?
Do not know the effect's name	motion-prompt, 192 names
Reference for pacing	Refs MCP (launch-heavy). Measure with PySceneDetect or hyperframes measure	For a talking head, measure 3 videos your audience watches
Reference for look	FILMGRAB by film title, Motionographer	A person pulls frames from ShotDeck or Frameset
Font	Fontsource	Google Fonts, Fontshare	Never
LUT or grade	hyperframes media-treatment, or ffmpeg curves	Lutify.me free, slaycamera/luts, G'MIC	You have a reference frame: a LUT from your own grade has clean rights
HDRI, texture, 3D	Poly Haven (CC0)	ambientCG, then 3D Asset Server across 26 sites	Rarely
Logo	The brand's press kit	Simple Icons, then SVGL	Never for a real brand. CC0 on a collection is not permission for the trademark
Icon	Lucide	Iconify, pinned to one set, license read

Exact queries: references/tested-queries.md. Every source with its route, license and score: references/all-sources.md.

Traps worth memorizing

Looks fine	Why it is not
BBC Sound Effects	A keyless API over 33,066 clips, but RemArc bars commercial use, and an agent never sees that license
Freesound, unfiltered	Mixes CC0 with NC and Sampling+. Always filter
Internet Archive	About 81% of "ocean" results carry no license URL, and results include broadcast TV
Coverr results	user-ai-* and *premium* ids mixed in: 11 of 61 on one page
Mixkit	A second, Restricted license sits beside the free one, so check each item
unDraw	Its license bars automated search and download, and copied "17 assets" lists tell you to hand it to Claude
MusicGen, local	facebook/musicgen-small is CC-BY-NC-4.0, and HyperFrames' free music route can fall back to it
video-talkcraft	Listed as free on X, but PolyForm Noncommercial
Openverse	The most-saved source on X and HyperFrames' default for SFX, but unreliable when tested. Never a hard dependency
Iconify	One API, mixed licenses: 53 of 276 sets are CC BY, 6 GPL, 2 non-commercial

Also check products, not only videos: Remotion needs a paid company license above 3 employees. GSAP's terms bar visual no-code builders that compete with Webflow, while using it in a video is fine. React Bits bars reselling components.

The full list of 36, with evidence: references/traps.md.

When a need is not listed

1. Search varg How-To once: curl -s 'https://api.varg.ai/v2/skills/search?q=QUERY&limit=5'. (Disclosure: varg makes this skill and that catalog. Rank it by what it returns.)
2. For a 3D or game asset, search 3D Asset Server.
3. Try one open source with a license field. If nothing matches, generate.

Adding a key

The free keys change the answer for B-roll. Ask the person only when the job needs it:

Key	Unlocks	Where
PEXELS_API_KEY	B-roll search with orientation filters	https://www.pexels.com/api/
PIXABAY_API_KEY	B-roll fallback	https://pixabay.com/api/docs/
FREESOUND_API_KEY	License filter in an API, with durations	https://freesound.org/apiv2/apply