https://github.com/mikolalysenko/pitch-shift

Variable speed pitch shifter written in JavaScript
https://github.com/mikolalysenko/pitch-shift

Last synced: about 2 months ago
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Variable speed pitch shifter written in JavaScript

• Host: GitHub
• URL: https://github.com/mikolalysenko/pitch-shift
• Owner: mikolalysenko
• License: mit
• Created: 2013-06-18T15:09:49.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-06-18T22:14:04.000Z (over 11 years ago)
• Last Synced: 2024-10-26T07:34:11.606Z (about 2 months ago)
• Language: JavaScript
• Homepage: http://mikolalysenko.github.io/pitch-shift/
• Size: 1.05 MB
• Stars: 79
• Watchers: 7
• Forks: 15
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
pitch-shift

===========

A variable speed pitch shifter written in JavaScript.

[Here is a demo you can try in your browser!](http://mikolalysenko.github.io/pitch-shift/)

## Example

Here is a simplified psuedo-example:

```javascript

//Create a pitch shifting object

var shifter = require("pitch-shift")(

  function onData(frame) {

    //Play / write out frame.  Called whenver data is ready

  },

  function onTune(t, pitch) {

  

    console.log("Got pitch ", pitch, " at time ", t)

    

    //This is the amount to scale the sample by

    return 1.0

  })

  

//Feed some data to the shifter

shifter(new Float32Array([1, 1, 0, 1, 0, 0, 0 /* ... etc */ ]))

```

For a more complete working example, check out test/test.js or example/index.js

## Install

    npm install pitch-shift

### `require("pitch-shift")(onData, onTune, options)`

Creates a pitch shifting function

* `onData(frame)` Called when a pitch shifted frame is ready.

* `onTune(t, pitch)` Called when a frame of audio needs to be processed.

* `options` An object full of options to pass to the pitch shifter

    + `frameSize` size of frame to process (default `2048`)

    + `hopSize` the distance between frames in samples.  Must divide frame size.  (default `frameSize/4`)

    + `dataSize` maximal allowable size of a data frame (default `frame_size`)

    + `sampleRate` Conversion factor from samples to seconds. (default `44100`)

    + `analysiWindow` analysis window.  must be a typed array with length equl to frame size (defaults to Hann window)

    + `synthesisWindow` synthesis window.  must be a typed array with length equal to frame size (defaults to Hann window)

    + `threshold` peak detection threshold.  Set to 1.0 to always take maximum, otherwise set lower to detect half tones.  (default `0.9`)

    + `minPeriod` Minimal resolvable period.  (default `sampleRate/400`)

**Returns** A function that you call with a frame of data.

## Credits

(c) 2013 Mikola Lysenko. MIT License

Gettysburg adress reading by Britton Rea.  Recording obtained from the Internet archive.  http://archive.org/details/GettysburgAddress