WebAudioFont v1.43

WebAudioFont is a set of resources and associated technology that uses sample-based synthesis to play musical instruments in browser.

Parts of WebAudioFont

Library of sounds
Metadata that describe how to play sounds
WebAudioFontPlayer.js that uses metadata and sounds for playing instruments
Catalog of available sounds
Catalog of compressed sounds

Underlaying technology

WebAudioFont uses Web Audio API to play instruments.

Synthesizer uses wavetables to play sound.

Use cases

Virtual instruments: Drums, Piano, Pan Flute
Interactive music generated on the fly: Melody loop
Sound effects for non-music applications: Car sound

How to use

Minimal HTML page

<html>
	<head>
		<script src='WebAudioFontPlayer.js'></script>
		<script src='webaudiofont/32.0.Accoustic_32Bsaccousticbs_461_460_45127.js'></script>
		<script>
			var AudioContextFunc = window.AudioContext || window.webkitAudioContext;
			var audioContext = new AudioContextFunc();
			var player=new WebAudioFontPlayer();
		</script>
	</head>
	<body>
		<p><a href='javascript:player.queueWaveTable(audioContext, audioContext.destination, _tone_Accoustic_32Bsaccousticbs_461_460_45127, 0, 12*4+7, 2);'>click!</a></p>
	</body>
</html>

This code plays instrument _tone_Accoustic_32Bsaccousticbs_461_460_45127 from 32.0.Accoustic_32Bsaccousticbs_461_460_45127.js with pitch 55. See simple example.

How to use catalog of sounds:

open index page
find instrument
copy name of file to include instrument data
copy name of variable to refer to instrument
add this info to a page

Sound file format

Each file looks like this:

console.log('load _tone_Harp000087_461_460_45127');
var _tone_Harp000087_461_460_45127={
	zones:[
		{
			midi:46
			,originalPitch:5700
			,keyRangeLow:0
			,keyRangeHigh:62
			,loopStart:3340
			,loopEnd:3841
			,coarseTune:0
			,fineTune:0
			,sampleRate:22050
			,ahdsr:true
			,sample:[0,-16,-17,97,124,-9, ...
		}
		,{
			midi:46
			,originalPitch:7001
			,keyRangeLow:63
			,keyRangeHigh:76
			,file:'4f67675300020

It creates object and assigns it to a global variable.

Each instrument consists of one or more zones, each zone has own properties for wavetable. Files contains of array with audio data. You can use instruments locally without CORS problem.

'sample' is an array of 16bit values with PCM data
'file' is a string with HEX numbers of any supported audio file

You need to add <body onload='player.adjustPreset(audioContext,selectedPreset);'> for compressed sounds to avoid delay of sample data parsing.

Some wavetables uses loops and AHDSR volume.

Player

WebAudioFontPlayer has function queueWaveTable (audioContext, target, preset, when, pitch, duration, volume, slides)

Parameters:

audioContext - AudioContext
target - a node to connect, for example audioContext.destination
preset - variable with instrument preset
when - when to play, audioContext.currentTime or 0 to play now, audioContext.currentTime + 3 to play after 3 seconds
pitch - note pitch from 0 to 127, for example 2+12*4 to play D of fourth octave (use MIDI key for drums)
duration - note duration in seconds, for example 4 to play 4 seconds
volume - 0.0-1.0 volume
slides - array of pitch bends

Function queueWaveTable returns envelope object. You can use this object to cancel sound or access to AudioBufferSourceNode.

All examples

WebAudioFontExampleAll.html - links to examples.
WebAudioFontExampleSimple.html - simple example.
WebAudioFontExampleDrums.html - virtual drums. This example shows using of drum instruments.
WebAudioFontExamplePiano.html - virtual piano. This example shows using of tone instrument.
WebAudioFontExampleFlute.html - virtual Pan flute. This example shows using of Envelope objects to start and stop a note playing.
WebAudioFontExampleVoice.html - two voice connected to different AudioNodes. This example shows how to create chain of AudioNodes and handle each instrument individually.
WebAudioFontExampleFx.html - sound slides from one pitch to another one. This example shows how to access AudioBufferSourceNode of played note.
WebAudioFontExampleTune.html - music loop. This example shows how to create and modify music in realtime.
WebAudioFontExampleTune2.html - music loop. This example shows how to code music.
WebAudioFontExampleTune3.html - music loop. This example shows how to code music.
WebAudioFontExampleTune4.html - music loop. This example shows how to code music with compressed samples.
WebAudioFontExampleTouch.html - multitouch beatpad. This example shows how to optimize application for mobile devices.
WebAudioFontExampleSelector.html - preset selector. This example shows how to load JS presets dynamically.
WebAudioFontExampleBend.html - music loop. This example shows how to use pitch bend.
WebAudioFontExampleMIDI.html - music loop. This example shows how to catch MIDI events.
https://jsbin.com/zabike/edit?html,output - music loop. This example shows how to exchange code.

chrislo / webaudiofont