SpessaSynth logo

A powerful SF2/DLS/MIDI JavaScript library for the browsers.

This is a WebAudioAPI wrapper for the spessasynth_core library.

It allows you to:

Play MIDI files using SF2/SF3/DLS files!
Read and write MIDI files!
Write SF2/SF3 files!
Convert DLS to SF2! (and back!)
and more!

SpessaSynth Project index

spessasynth_core - SF2/DLS/MIDI library
spessasynth_lib (you are here) - spessasynth_core wrapper optimized for browsers and WebAudioAPI
SpessaSynth - online/local MIDI player/editor application
SpessaFont - online SF2/DLS editor

TIP: Looking for a bare JS version that works without WebAudioAPI? Try spessasynth_core!

npm install --save spessasynth_lib

Project site (consider giving it a star!)

Made with spessasynth_lib

Complete documentation

Basic example: play a single note

import { Synthetizer } from "spessasynth_lib"

const sfont = await (await fetch("soundfont.sf3")).arrayBuffer();
const ctx = new AudioContext();
// make sure you copied the worklet processor!
await ctx.audioWorklet.addModule("./worklet_processor.min.js");
const synth = new Synthetizer(ctx.destination, sfont);
document.getElementById("button").onclick = async () =>
{
    await ctx.resume();
    synth.programChange(0, 48); // strings ensemble
    synth.noteOn(0, 52, 127);
}

Audio may sometimes sound distorted in Chromium-based browsers: Chrome, Edge, Brave, etc. due to a Chromium Bug. I can't do anything about it, only hope that it gets fixed. Please consider voting for it on the bug tracker to get it fixed!

Current Features

All the features of spessasynth_core!

On top of that...

Modular design: Easy integration into other projects (load what you need)
Detailed documentation: With examples!
Easy to Use: Basic setup is just two lines of code!
No external dependencies: Just spessasynth_core!
Reverb and chorus support: customizable!
Export audio files using OfflineAudioContext
Written using AudioWorklets:
- Runs in a separate thread for maximum performance
- Does not stop playing even when the main thread is frozen
- Supported by all modern browsers
High-performance mode: Play Rush E! note: may kill your browser ;)

TODO

Enhance the built-in chorus and reverb effects (suggestions welcome!)

Special Thanks

FluidSynth - for the source code that helped implement functionality and fixes
Polyphone - for the soundfont testing and editing tool
Meltysynth - for the initial low-pass filter implementation
RecordingBlogs - for detailed explanations on MIDI messages
stbvorbis.js - for the Vorbis decoder
fflate - for the MIT DEFLATE implementation
foo_midi - for useful resources on XMF file format
Falcosoft - for help with the RMIDI format
Christian Collins - for various bug reports regarding the synthesizer
And You! - for checking out this project. I hope you like it :)

License

SoundFont® is a registered trademark of Creative Technology Ltd.

Package detail

spessasynth_lib

readme