fluid-js

fluid-js

fluid-js is a library that generates audio data (frames). fluid-js uses wasm version of FluidSynth.

Install

npm install --save fluid-js

Usage

From main thread

Copies dist/fluid.js (or dist/fluid.min.js) and externals/libfluidsynth-2.0.1.js (libfluidsynth JS file) to your project, and writes <script> tags as following order:

<script src="libfluidsynth-2.0.1.js"></script>
<script src="fluid.js"></script>

When scripts are available, you can use APIs via Fluid namespace object.

// Prepare the AudioContext instance
var context = new AudioContext();
var synth = new Fluid.Synthesizer();
synth.init(context.sampleRate);

// Create AudioNode (ScriptProcessorNode) to output audio data
var node = synth.createAudioNode(context, 8192); // 8192 is the frame count of buffer
node.connect(context.destination);

// Load your SoundFont data (sfontBuffer: ArrayBuffer)
synth.loadSFont(sfontBuffer).then(function () {
    // Load your SMF file data (smfBuffer: ArrayBuffer)
    return synth.addSMFDataToPlayer(smfBuffer);
}).then(function () {
    // Play the loaded SMF data
    return synth.playPlayer();
}).then(function () {
    // Wait for finishing playing
    return synth.waitForPlayerStopped();
}).then(function () {
    // Wait for all voices stopped
    return synth.waitForVoicesStopped();
}).then(function () {
    // Releases the synthesizer
    synth.close();
}, function (err) {
    console.log('Failed:', err);
    // Releases the synthesizer
    synth.close();
});

(Above example uses Web Audio API, but you can use Synthesizer without Web Audio, by using render() method.)

If you prefer to load fluid-js as an ES module, you can use import statement such as import * as Fluid from 'fluid-js'.

Notes:

• fluid.js intends the ES2015-supported environment. If you need to run the script without errors on non-ES2015 environment such as IE11 (to notify 'unsupported'), you should load those scripts dynamically, or use transpiler such as babel.
• libfluidsynth JS file is not import-able and its license (LGPL v2.1) is differ from fluid-js's (BSD-3-Clause).

With AudioWorklet

fluid-js supports AudioWorklet process via dist/fluid.worklet.js (or dist/fluid.worklet.min.js). You can load fluid-js on the AudioWorklet as the following code:

var context = new AudioContext();
context.audioWorklet.addModule('libfluidsynth-2.0.1.js')
    .then(function () {
        return context.audioWorklet.addModule('fluid.worklet.js');
    })
    .then(function () {
        // Create the synthesizer instance for AudioWorkletNode
        var synth = new Fluid.AudioWorkletNodeSynthesizer();
        synth.init(context.sampleRate);
        // You must create AudioWorkletNode before using other methods
        // (This is because the message port is not available until the
        // AudioWorkletNode is created)
        audioNode = synth.createAudioNode(context);
        audioNode.connect(context.destination); // or another node...
        // After node creation, you can use Synthesizer methods
        return synth.loadSFont(sfontBuffer).then(function () {
            return synth.addSMFDataToPlayer(smfBuffer);
        }).then(function () {
            return synth.playPlayer();
        }).then(function () {
            ...
        });
    });

API

Creation of Synthesizer instance

These classes implement the interface named Fluid.ISynthesizer.

• Fluid.Synthesizer (construct: new Fluid.Synthesizer())
  • Creates the general synthesizer instance. No parameters are available.
• Fluid.AudioWorkletNodeSynthesizer (construct: new Fluid.AudioWorkletNodeSynthesizer())
  • Creates the synthesizer instance communicating AudioWorklet (see above). No parameters are available.

Fluid.ISynthesizer methods

(Not documented yet. Please see dist/lib/ISynthesizer.d.ts.)

License

fluid-js is licensed under BSD 3-Clause License except for the files in externals directory. For licenses of the files in externals directory, please read externals/README.md.