@audio/filter-derivative

Derivative / integral — FFmpeg aderivative/aintegral first-difference & running-sum pair

npm install @audio/filter-derivative

import { derivative, integral } from '@audio/filter-derivative'

First-difference and running-sum — an exact inverse pair (FFmpeg's aderivative/aintegral).

$H_d(z) = 1 - z^{-1}$ (derivative)  /  $H_i(z) = \dfrac{1}{1 - z^{-1}}$ (integral, leak=1)

Inverse pair: integral at leak: 1 exactly reconstructs the input passed to derivative — the running sum telescopes Leak: leak < 1 bleeds the accumulator per sample so DC-biased material converges to a finite value ($\frac{x_{dc}}{1-\text{leak}}$) instead of drifting

derivative(buffer, {})
integral(buffer, { leak: 1 })    // 1 = exact FFmpeg aintegral; <1 for stability on real program material

| Function | Param | Default | | |---|---|---|---| | derivative | prev | 0 | previous sample (persisted) | | integral | leak | 1 | 1 = exact inverse of derivative; <1 anti-drift | | | acc | 0 | running-sum accumulator (persisted) |

Pass the same params object on every call to persist state across blocks.

Use when: edge/transient detection (derivative), reconstructing a signal from its differenced form (integral), envelope-adjacent accumulation.

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

MIT © audiojs