https://github.com/fritzo/wavencoderjs

A fast cross-browser riff wave encoder for real-time audio synthesis in HTML5
https://github.com/fritzo/wavencoderjs

html5-audio javascript web-worker

Last synced: 11 months ago
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A fast cross-browser riff wave encoder for real-time audio synthesis in HTML5

• Host: GitHub
• URL: https://github.com/fritzo/wavencoderjs
• Owner: fritzo
• Created: 2012-01-18T23:09:48.000Z (over 14 years ago)
• Default Branch: master
• Last Pushed: 2012-02-15T22:41:49.000Z (about 14 years ago)
• Last Synced: 2025-05-05T16:55:14.371Z (about 1 year ago)
• Topics: html5-audio, javascript, web-worker
• Language: JavaScript
• Homepage:
• Size: 105 KB
• Stars: 23
• Watchers: 4
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

          
# WavEncoder #

WavEncoder is a fast cross-browser riff wave encoder for real-time audio synthesis in HTML5.

Works in Web Workers and in the main window

(in contrast to encoders using window.btoa).

Dual licensed under the [MIT](http://www.opensource.org/licenses/MIT)

or [GPL Version 2](http://www.opensource.org/licenses/GPL-2.0) licenses.

## Examples ##

To play 1 sec of noise in the main window, we can

    

    

      var samples = [];

      for (var t = 0; t < 22050; ++t) {

        samples[t] = 2 * Math.random() - 1;  // in the interval [-1,1]

      }

      var datauri = WavEncoder.encode(samples);

      var audio = new Audio(datauri);

      document.onload(function(){ audio.play(); });

    

WavEncoder objects are optimized to create many samples of the same length.

A typical use case is to generate a set of tones, say in a web worker

    includeScripts('wavencoder.js');

    

    var sampleRateHz = 44100;

    var numSamples = 1 * sampleRateHz;                 // 1 sec

    var baseFreq = 2 * Math.PI * 27.5 / sampleRateHz;  // A0

    var wavEncoder = new WavEncoder(numSamples, {sampleRateHz: sampleRateHz});

    var tones = [];

    var samples = [];

    for (var n = 0; n < 88; ++n) {

      var freq = baseFreq * Math.pow(2, n/12);

      for (var t = 0; t < numSamples; ++t) {

        samples[t] = Math.sin(freq * t);

      }

      tones[n] = wavEncoder.encode(samples);

    }

    postMessage(tones);