@audio/shift-hybrid

Hybrid pitch shift — runs phase-lock + WSOLA in parallel, crossfades by transient confidence

npm install @audio/shift-hybrid

import hybrid from '@audio/shift-hybrid'

Runs phaseLock and wsola in parallel, crossfades sample-by-sample by spectral-flux transient confidence. Tonal regions resolve via the phase vocoder; attacks resolve via WSOLA similarity search, time-aligned against phaseLock before blending so the two engines' attacks land together.

hybrid(audio, { ratio: 1.5 })
hybrid(audio, { ratio: 1.5, hybridThreshold: 0.6 })

| Param | Default | | |---|---|---| | hybridThreshold | 0.8 | Spectral-flux z-score for full WSOLA blend |

Preserves tonal phase coherence + attack shape — simultaneously. Destroys CPU budget (≈2×), formants.

| f0 err | THD% | alias | attack corr | formant dist | phase coh | shift | |-------:|-----:|------:|------------:|-------------:|----------:|------:| | 0.00 | 0.0 | 0.000 | 0.984 | 1.423 | 0.999 | 1.824 |

Same phaseLock-derived numbers as phaseLock/transient on this non-percussive suite — the WSOLA blend never activates because nothing here crosses hybridThreshold. Worst shift score among the frequency-adjacent methods for the same reason: it's carrying wsola's parallel computation for a blend that stays at zero.

Use when: Mixed dynamic material where a single domain compromises the other. Not for: Pure tonal (just use phaseLock) or pure percussive (just use transient).

Stream

let write = hybrid({ ratio: 1.5 })
let out = write(inputBlock)
let tail = write()  // flush

hybrid buffers the whole input; write(chunk) accumulates and the batch algorithm runs once on write() (flush, no argument), returning everything at once.

Data

Input is a Float32Array (mono) or an array of Float32Array channels ([left, right, ...]) — anything else throws TypeError. ratio here is a fixed number for the whole call — a function or Float32Array throws.

Part of @audio/shift — the shift family umbrella. This README is generated from the umbrella docs.

MIT © audiojs