Crate Capture

CC0 (say: see-see-zero) is a public domain dedication. The person who made the work gives up all their copyright, everywhere, so anyone can copy, change, sell and share it with no credit and no permission. See licence in the Word Lab.

It only waives copyright. It does not cover trademarks, a person's privacy or likeness (a recognisable voice, for example), or rights that other people hold in the work. So a CC0 label is a strong claim, not a guarantee. You are checking whether the claim is true.

Public domain by age is different: no one dedicated it, its copyright simply ended. That depends on the country, and a song and a recording of it can end on different dates. Old US recordings from before 1923 are public domain in the US, and 1925 recordings joined them on 1 January 2026. Other countries run different clocks.

One more thing to know: in some countries, performers and record makers hold rights (for example to be paid when a recording is broadcast) that cannot always be given up, even by a CC0 dedication. This is why the best evidence is the maker's own written statement, saved with the untouched original. If a track will be used somewhere that matters, ask the person you are sending it to what proof they need.

1. The licence is on the page. Save the address and, if you can, a screenshot or a saved copy of the page. Pages change.
2. The licence is in the download. Open the zip. Read any readme, text file or tags. If it says something stricter than the page, believe the stricter one.
3. The uploader is the maker (or the piece is public domain by age). Read the profile. Does the account make this kind of music? Is there a pattern of uploads that look like other people's?
4. No samples, covers or borrowed voices. Listen for a recognisable riff, vocal or drum break. Search a distinctive phrase. "Free" remixes of protected songs are not free.
5. Both rights are covered. The recording and the composition. A CC0 recording of someone else's song is not enough.
6. Nothing else restricts it. A site rule such as "not on its own", a brand name in the title, a person's name or voice.

A real example from this project's own sound work: a pack labelled CC0 on its page contained a text file saying CC BY 3.0. It was logged and credited as CC BY, and kept out of the CC0 set.

• Start narrow, then widen. Search by mood and use ("slow dark ambient loop"), then by instrument, then by tempo, then by collection. Write down the searches that worked.
• Follow creators, not just tracks. If one creator publishes everything as CC0, their whole page is a source. Kenney and the Open Goldberg Variations are examples.
• Use a finder, then go to the original. Openverse searches several open sites at once. Always open the original page for the checks.
• Use the filters. Freesound, OpenGameArt, Openverse, Free Music Archive, ccMixter and the Internet Archive can all limit results to CC0 or public domain. The Tools tab has the exact settings and commands.
• Look at collections and tags, then check each item anyway. A tag is a hint, not proof.
• Old music, new performance. Public domain scores (IMSLP, Mutopia) plus your own recording make music you can dedicate yourself.
• Write your own. Nothing beats it: you know exactly where every sound came from.
• Keep a "searched" list (the Notes field in each find, or your own file) so you do not repeat yourself.

The Sources tab lists 16 places with what to expect from each, and the list of things that look free but are not.

• Use the site's own download button or its official API or command-line tool. Do not record a stream or use a "downloader" site.
• Keep the original file and the whole zip with its readme. Do not re-encode the original: make a copy to work on.
• Make the original read-only, and keep it in a folder named after the source.
• Check the file really is what the page said (length, format) and that it opens.
• Compute its SHA-256 fingerprint straight away. Crate Capture does this for you in the browser (nothing is uploaded), or use the command in the Tools tab.
• Large or many files: use the site's official tool (for example the Internet Archive's ia) rather than clicking one at a time, and be kind: do not hammer a small site.

Provenance means the history of where something came from. For each find, write down:

• Title, creator, the page address, and the day you checked.
• Which licence, the licence address, and the evidence: exactly where you saw it ("licence box on the page; readme.txt line 3").
• The six checks, ticked only when true.
• The file name, size, and SHA-256 fingerprint.
• Your rating and notes.

In My finds a track is marked Ready only when all of that is present. Export a provenance sheet (CSV), a LICENSES.txt and the whole log (JSON) to go with whatever you hand over. Keep a copy of the JSON somewhere safe: clearing the browser's data erases the log.

• Listen on speakers and on headphones, at a normal volume, all the way through.
• Rate it in My finds: Love (I would be proud to submit it), Keep, Maybe, Drop.
• Ask: does it have a clear start and end? Is it clean (no clipping, no hiss, no stray noise)? Does it loop if it should? Does it fit with the rest of what you are sending?
• A short, honest set of tracks you love beats a long list you are unsure about.

• Keep the original untouched. Prepare a copy.
• Loudness: measure first, then adjust only if needed. Commands are in the Tools tab. Do not make things louder just to be louder: leave headroom (a true peak under about -1 dBTP).
• Names: source_title_creator_licence in lower case, no spaces. Crate Capture suggests one.
• Tags: write the licence and the source address into the file's metadata, so the information travels with the file.
• Format: WAV or FLAC for delivery unless the receiver asks for something else. Do not turn an MP3 into a WAV and call it lossless.

A tidy pack is easy to trust:

my-cc0-pack/
  audio/                     the prepared files
  originals/                 optional: the untouched downloads
  LICENSES.txt               from Crate Capture
  provenance.csv             from Crate Capture
  README.txt                 who you are, what this is, the date

Read the receiver's own rules first (format, length, naming, what they want to know). If you do not know where you are sending it yet, build the pack anyway: it will be ready.

If it is your own music: say so plainly in the README ("I made every part of these tracks and dedicate them to the public domain under CC0 1.0"), name any collaborators and say they agreed, and remember CC0 cannot be undone.

Mark it Rejected in your log and keep the note about why. If it was on a site, use that site's report option (Freesound has "Flag it" on each sound). If you already sent it, tell the person you sent it to straight away and offer to remove it. Everyone makes this mistake at some point; hiding it is the only real mistake.