@audio/mir-key

Key detection — Krumhansl–Schmuckler: Pearson correlation between a chroma vector and each of 24 rotated Krumhansl–Kessler (1982) major/minor key profiles. Highest correlation wins.

npm install @audio/mir-key

import key, { KK_MAJOR, KK_MINOR } from '@audio/mir-key'

let r = key(chromaVec)
// { tonic: 0..11, mode: 'major'|'minor', label: 'C'|'Am'|…, confidence: -1..1, scores: [{label, score}, …] }

scores holds all 24 candidates sorted descending by correlation — scores[0] is the winner (confidence mirrors its score).

input accepts a single 12-D chroma vector, or an array of chroma frames (averaged across frames first) — pass a chromagram directly to key a whole passage instead of one instant.

Options: - profile — { major: number[12], minor: number[12] } override for the reference key profiles (default Krumhansl–Kessler KK_MAJOR/KK_MINOR, also exported directly)

Use when: a single global-key estimate is enough; for time-varying tonality, run key() over a sliding window of chroma frames.

Part of @audio/mir.