sonoport/webaudioloader

Caching Loader (with optional decode) audio files to be used with WebAudio

WebAudioLoader

Caching Loader and Decoder for audio files to be used with Web Audio.

Usage:

var WebAudioLoader = require("webaudioloader");

var audioContext = new AudioContext();

var options = {
	context : audioContext,
	cache : true,
	maxCacheSize : 2000,
	onprogress : function (event){
		console.log('Loading some files...', event.loaded/event.total);
	}
}

var wal = new WebAudioLoader(options);

wal.load('http://www.example.com/audio.mp3', {
		onload : function (err, buffer){
		if(!err){
			console.log('Loaded file of duration', buffer.duration);
		}
	},
});

Why WebAudioLoader

• Easy API (deals with loading and decoding audio for you) for XHR loading of audio.
• Uses LRU Cache for caching decoded audio.
• Uses node style callbacks (err, buffer) to return decoded buffers.
• Registers a global single instance and returns a reference if one is found.

Note

• Web Audio only works in a browser (for now), so does this module.

Install

1. With npm do:

   npm install webaudioloader

2. Use browserify:

   var WebAudioLoader = require('webaudioloader')

   and

   browserify myapp.js > bundle.js

3. Standalone (AMD, global object) builds are avilable here.

API

Constructor

eg : var wal = new WebAudioLoader(options);

• option object can have following optional properties

  • cache : boolean - enable/disable cache globally. Default is true.
  • maxCacheSize : Number - maximum size in kB of cached audio buffers. Default is 1000.
  • onload : Function - global callback when a load operation is complete. The callback has node style return arguments callback(err, buffer).
  • onprogress : Function - global callback when a load operation is in progress. The callback return a progress Event.
  • context : AudioContext - an AudioContext to use for decoding the audio.

Properties

• onload : Function - global callback when a load operation is complete. The callback has node style return arguments callback(err, buffer).

  eg : wal.onload = function(){};

• onprogress : Function - global callback when a load operation is in progress. The callback return a progress Event.

  eg : wal.onprogress = function(){};

• cache : boolean - enable/disable cache globally.

  eg : wal.cache = false;

Methods

• load : Main API method to load ()and decode) a given AudioFile.

  eg :

   wal.load('http://www.example.com/audio.mp3');
   wal.load([object File]);
   wal.load('http://www.example.com/audio.mp3', options);

  • the source argument can either be a URL String or a File object

  • option object can have following optional properties

    • decode : boolean - toggle if the audio file should be decoded. If decoded the onload callback returns an AudioBuffer, else it returns an ArrayBuffer.
    • cache : boolean - if the audio from this specific load call should be cached. Overrides the global property.
    • onload : Function - callback when this specific load operation is complete. The callback has node style return arguments callback(err, buffer).
    • onprogress : Function - callback when this specific load operation is in progress. The callback return a progress Event.

• flushCache : Resets the internal cache of the loader.

  eg : wal.flushCache();

License

MIT