com.originalpictures.audfprint.1
audfprint landmarks audio fingerprint: Original Pictures' deployment of audfprint by Dan Ellis, with its own parameters, calibration and match threshold.
- Match threshold op.audfprint.aligned-hashes-20.v1
- Encoded media types: audio/mp4, audio/mpeg, audio/wav
- Registration requested with the C2PA soft binding algorithm list
Identity
| Field | Value |
|---|---|
Algorithm identifier (alg) | com.originalpictures.audfprint.1 |
| Type | Fingerprint |
| Decoded media type | Audio |
| Encoded media types | audio/mp4, audio/mpeg, audio/wav |
| Underlying algorithm | audfprint by Dan Ellis |
| Provider identity and version | org.dpwe.audfprint cb03ba99feaf-d20-sr11025-h20 |
API value (fingerprint_algorithms) | audfprint (computed when a request names it) |
| Calibration | op.audfprint.calibration.v1 |
| Match threshold | op.audfprint.aligned-hashes-20.v1 |
| Runtime revisions | op.audio-bindings.mm05.1 |
| Licences | Code: MIT (dpwe/audfprint LICENSE). Weights: n/a (no learned weights). |
Pinned artefacts
Every file the runtime loads or builds from is pinned by SHA-256; a file with any other hash is refused.
| File | Kind | SHA-256 | Size | Source |
|---|---|---|---|---|
audfprint-source.tar.gz | source | 7fa07bada480cd0e65379780ce8b37facbce93bbacf7eb0b9486f017c7b8936e | 2.1 MB | source |
How the fingerprint is computed
The audio is resampled to 11,025 Hz; audfprint picks spectral peaks at landmark density 20 and pairs them into 20-bit landmark hashes, each with its time offset. At most the first 10 minutes are analysed.
| Parameter | Value |
|---|---|
| Implementation | dpwe/audfprint at cb03ba99 (analysis only) |
| Sample rate | 11,025 Hz |
| Density and hash | 20 per second, 20-bit hashes |
| Keyed | No |
How matching works
A candidate matches when at least 20 landmark hashes agree on one time offset (within one analysis frame). A fingerprint is compared only with fingerprints of the same algorithm, calibration and threshold, within the account that signed the file. Survives loud background speech or music and re-recording; complements Chromaprint.
What a positive result means
A match means the file looks or sounds like a file the signer's account signed, closely enough to pass the threshold above. It points to that file's C2PA manifest, which declares its origin. It is a probabilistic lead, not cryptographic proof: a fingerprint matches similar content, can miss heavily edited copies, and says nothing about whether the content is true. The signed manifest, where it survives, is the proof.
Measured performance
On Original Pictures' 2026 fingerprint benchmark (method audfprint), at the production threshold, which corresponds to a query-level false-match rate of 1%, 66.0% of transformed copies (95% interval 65.4% to 66.7%) were matched to their original, over the benchmark's transformations of its fixed corpus (re-encoding, resizing, cropping and overlays, and the edits typical of the media type). These are measurements on a fixed corpus, not a guarantee for every file.
The value a soft-binding assertion would carry
- Value: The sorted, unique landmarks as big-endian 32-bit time and 32-bit hash pairs, as base64: the bytes Original Pictures stores. At the landmark rate the runtime is bounded for, 10 minutes is about 131 KB before base64.
- Scope: A timespan: the first 10 minutes, or the whole file if shorter.
- Encoding note: The C2PA schema defines a soft-binding value as a byte string. Original Pictures' signing engine writes it as text, as it already does for the ISCC binding, so the form above is the text a manifest would carry.
- Emission: Planned after the identifier is assigned, subject to the value size.
How to check a file
- Content Credentials. Any C2PA-aware validator can read and check the manifest of a file that still carries one, without calling Original Pictures.
- The fingerprint. Fingerprint recovery runs inside a verification:
POST /v1/verificationson the Original Pictures API. When no manifest can be read, the verification compares the file's fingerprints with the recorded ones and reports a single match as recovery-only (VALIDATION_RECOVERY_ONLY), never as cryptographic validity; several plausible matches fail closed as ambiguous. Recovery searches only the bindings of the account that runs the verification. See lookup and recovery and fingerprints. - There is no public soft-binding resolution API. A third party can check a file on the signer's hosted verify page, if the signer publishes one; that page searches the signer's own fingerprints only when the signer has switched recovery on (
recover_own_assets). Otherwise, contact the signer or us. - Comparing values yourself. audfprint is public, so once the value is in a manifest anyone can analyse a candidate with the same parameters and count aligned hashes.
Relation to C2PA
When a fingerprint algorithm has an identifier on the C2PA soft-binding algorithm list, the manifest can carry a c2pa.soft-binding assertion that names it in its alg field. Registration for com.originalpictures.audfprint.1 has been requested with the C2PA soft binding algorithm list; no identifier has been assigned yet. Until one is, and until Original Pictures ships the change that writes it, no manifest names this fingerprint: it is a server-side recovery signal only. Today the one fingerprint a manifest carries is ISCC Image-Code (io.iscc.v0). This page is the entry's informational URL.
Status and contact
- Status: registration requested with the C2PA soft binding algorithm list.
- Contact: hello@originalpictures.com
- Last updated: 2026-11-08. The values on this page are generated from the production registry.
- All Original Pictures soft-binding algorithms