https://github.com/audiojs/audio-oscillator

Generate periodic oscillation into an array/audiobuffer
https://github.com/audiojs/audio-oscillator

audiojs

Last synced: 25 days ago
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Generate periodic oscillation into an array/audiobuffer

• Host: GitHub
• URL: https://github.com/audiojs/audio-oscillator
• Owner: audiojs
• License: mit
• Archived: true
• Created: 2015-10-04T01:55:10.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2020-05-25T04:08:32.000Z (over 4 years ago)
• Last Synced: 2024-04-26T11:21:06.653Z (8 months ago)
• Topics: audiojs
• Language: JavaScript
• Homepage:
• Size: 60.5 KB
• Stars: 27
• Watchers: 14
• Forks: 2
• Open Issues: 4
• Metadata Files:
  • Readme: readme.md
  • License: license.md

Awesome Lists containing this project

• awesome-javascript-audio - audiojs/audio-oscillator - Generate periodic oscillation into an array/audiobuffer using a simple API (Sound creation / Low frequency oscillators ("LFOs"):)

README

        
# audio-oscillator [![Build Status](https://travis-ci.org/audiojs/audio-oscillator.svg?branch=master)](https://travis-ci.org/audiojs/audio-oscillator) [![unstable](https://img.shields.io/badge/stability-unstable-green.svg)](http://github.com/badges/stability-badges) [![Greenkeeper badge](https://badges.greenkeeper.io/audiojs/audio-oscillator.svg)](https://greenkeeper.io/)

Generate periodic oscillation data.

## Usage

[![$ npm install audio-oscillator](http://nodei.co/npm/audio-oscillator.png?mini=true)](http://npmjs.org/package/audio-oscillator)

```js

const oscillate = require('audio-oscillator/sine')

const output = require('web-audio-write')()

// render sine sound stream

let buf = new AudioBuffer({ channels: 2, sampleRate: 44100, length: 1024 })

;(async function frame() {

  await output(oscillate(buf, { frequency: 440 })))

  frame()

})()

```

## API

### `let array = oscillate.(length|dst, frequency=440|options?)`

Generate [periodic-function](https://ghub.io/periodic-function) `waveform` samples into a `dst` float array / array of arrays / _AudioBuffer_. If `length` is provided, a new mono `array` is created. The phase of consequently generated chunks is aligned, if the same array is passed multiple times.

```js

let oscillate = require('audio-oscillator')

let samples = new Float64Array(1024)

oscillate.sine(samples, 440)

// output array has additional properties of the data

// samples.phase, samples.frequency, samples.detune, samples.sampleRate

// next data phase is aligned with the previous data

oscillate.sine(samples)

```

#### `options`

Property | Default | Meaning

---|---|---

`frequency`, `f` | `440` | Frequency of oscillations, in Hz.

`detune` | `0` | Detune of oscillations `-100...+100`, in cents.

`phase`, `t` | `0` | Normalized initial phase of waveform, `0..1`.

`sampleRate`, `rate` | `44100` | Sample rate of output data.

#### `waveform`

Available waveforms with their additional options:

Type | Waveshape | Parameters

---|---|---

`'sin'` | ![sine](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/sine.png) |

`'cos'` | ![cosine](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/cosine.png) |

`'saw'` | ![sawtooth](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/sawtooth.png) | `inverse=false`

`'tri'` | ![triangle](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/triangle.png) | `ratio=0.5`

`'rect'` | ![square](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/square.png) | `ratio=0.5`

`'series'` | ![fourier](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/fourier.png) | `real=[0, 1]`, `imag=[0, 0]`, `normalize=true`

`'clausen'` | ![clausen](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/clausen.png) | `limit=10`

`'step'` | ![step](https://raw.githubusercontent.com/dfcreative/periodic-function/master/img/step.png) | `samples=10`

## Related

* [periodic-function](https://github.com/scijs/periodic-function) − a collection of periodic functions.

## License

© 2017 Dmitry Yv. MIT License