audio-loader

An simple and flexible audio buffer loader for browser:

var ac = new AudioContext()
var load = require('audio-loader')

// load one file
load(ac, 'http://example.net/audio/file.mp3').then(function (buffer) {
  console.log(buffer) // => <AudioBuffer>
})

// load a collection of files
load(ac, { snare: 'samples/snare.wav', kick: 'samples/kick.wav' },
  { from: 'http://example.net/'} ).then(audio) {
  console.log(audio) // => { snare: <AudioBuffer>, kick: <AudioBuffer> }
})

Features

Load single audio files or collection of them (either using arrays or data objects)
Load base64 encoded audio strings
Compatible with midi.js pre-rendered soundfonts packages

## Install

Via npm: npm i --save audio-loader or grab the browser ready file (4kb) which exports loadAudio as window global.

Usage

API: `load(ac, source, options)`

Param	Type	Description
ac	`AudioContext`	the audio context
source	`Object`	the object to be loaded
options	`Object`	(Optional) the load options for that object

Possible option keys:

from {Function|String}: a function or string to convert from file names to urls. If is a string it will be prefixed to the name: load(ac, 'snare.mp3', { from: 'http://audio.net/samples/' }) If it's a function it receives the file name and should return the url as string.
only {Array} - when loading objects, if provided, only the given keys will be included in the decoded object: load(ac, 'piano.json', { only: ['C2', 'D2'] })

Load audio files

You can load individual or collection of files:

var ac = new AudioContext()
load(ac, 'http://path/to/file.mp3').then(function (buffer) {
  // buffer is an AudioBuffer
  play(buffer)
})

// apply a prefix using options.from
load(ac, ['snare.mp3', 'kick.mp3'], { from: 'http://server.com/audio/'}).then(function (buffers) {
  // buffers is an array of AudioBuffers
  play(buffers[0])
})

// the options.from can be a function
function toUrl (name) { return 'http://server.com/samples' + name + '?key=secret' }
load(ac, { snare: 'snare.mp3', kick: 'kick.mp3' }, { from: toUrl }).then(function (buffers) {
  // buffers is a hash of names to AudioBuffers
  play(buffers['snare'])
})

Recursive loading

audio-loader will detect if some of the values of an object is an audio file name and try to fetch it:

var inst = { name: 'piano', gain: 0.2, audio: 'samples/piano.mp3' }
load(ac, inst).then(function (piano) {
  console.log(piano.name) // => 'piano' (it's not an audio file)
  console.log(piano.gain) // => 0.2 (it's not an audio file)
  console.log(piano.audio) // => <AudioBuffer> (it loaded the file)
})

Load soundfont files

You can load midi.js js soundfont files:

load(ac, 'acoustic_grand_piano-ogg.js').then(function (buffers) {
  buffers['C2'] // => <AudioBuffer>
})

Run tests and examples

To run the test, clone this repo and:

npm install
npm test

To run the example:

npm i -g beefy
beefy example/example.js

License

MIT License

olivia/audio-loader