@audio/spectral-zcr

Zero-crossing rate — fraction of consecutive samples whose sign differs (librosa zero_crossing_rate class).

npm install @audio/spectral-zcr

import zcr from '@audio/spectral-zcr'

let r = zcr(frame)   // 0…1, sign-change fraction over the frame

Time-domain, not spectral — no FFT, takes raw PCM directly. −0 counts as negative (matches librosa's np.signbit), so a hard-zero sample still registers a crossing against a preceding positive sample. High ZCR marks noisy/fricative/percussive content; low ZCR marks tonal/voiced content.

No options — zcr(data) takes only the signal.

Also exported as an audio.js stat manifest (./audio — mono-fold, 2048/512 frames, unwindowed, averaged over the take).

Part of @audio/spectral.