Kotlin Multiplatform SoundFont library

Library for sample-based synthesis to generate audio data. The library allows to load .sf2 and .sf3 files from memory. Is basically a KMP wrapper around TinySoundFont library.

The goal of this library is to allow operations on .sf2 files and generating audio in Kotlin Multiplatform projects. The library has batteries-included so no configuration is required.

Non goals:

• Audio playback
• Audio file export (such as WAV or MP3)
• File I/O operations
• Audio format conversion
• Resampling, mixing etc...

Platform support:

Android	iOS	Mingw X64	Linux X64	MacOs (Apple silicon)	Wasm	JS
✔️	✔️	✔️	✔️	✔️	⌛	✖️

---

Installation

This library is stored on Maven Central repository. To add library to Your project paste the following snippet in your TOML file.

[versions]
mikrosoundfont = "<latest_version>"

[libraries]
mikrosoundfont = { module = "io.github.lemcoder.mikrosoundfont:soundfont", version.ref = "mikrosoundfont" }

---

Usage

val sfBuffer   // .sf2 or .sf3 file bytes
    
MikroSoundFont.load(sfBuffer).use { soundFont ->
    // .. use soundFont to generate audio data
}

A SoundFont holds its samples in native memory until close() is called, so close it (or load it in use { }) when you are done with it.

SF3 files

.sf3 files store their samples compressed with Ogg Vorbis. load decodes all of them up front, so:

• loading takes noticeably longer than an .sf2 of the same size (seconds for a large font on a phone), so load off the main thread;
• the loaded SoundFont takes several times the file size in memory, as the samples are kept decoded.

Decoding uses stb_vorbis, which is not hardened against malformed data, so only load .sf3 files you trust.

Testing

The tests in soundfont/src/commonTest load an .sf2 and an .sf3 font and render audio through the native library:

• ./gradlew :soundfont:linuxX64Test or :soundfont:macosArm64Test runs them on the host (CI runs the Linux ones on every pull request);
• ./gradlew :soundfont:connectedAndroidDeviceTest runs them on a connected Android device or emulator.

License

This project is licensed under the Apache 2.0 License - see the LICENSE.md file for details