Multi-stream fingerprint match against an SQLite index of the score corpus:
- Timed hash streams — Shazam-style tempo-invariant triplet hashes (full texture) +
melody/bass 5-gram hashes, voted over a BPM×offset grid. Score: offset-peak
coherence, length-normalized (
peak / (hits + 100)).
- Windowed chromagram — per-beat pitch-class profile, slid in 30-beat windows
(rubato-tolerant) + a coarse texture timeline.
- Interval n-gram containment — rhythm-free skyline/bassline interval 4-gram overlap.
Immune to tempo drift; the strongest single signal for short fragments.
Full write-up: METHOD.md in practica-api.
Queries where the true piece missed the top-5, or lost rank-1 to a wrong answer.