dart_melty_soundfont 1.1.11 dart_melty_soundfont: ^1.1.11 copied to clipboard
A Soundfont synthesizer (i.e. '.sf2' player) written in pure Dart.
dart_melty_soundfont #
dart_melty_soundfont is a SoundFont synthesizer (i.e. '.sf2' player) written in pure Dart.
It is a port of MeltySynth (C#, MIT License) written by Nobuaki Tanaka, to Dart.
https://github.com/sinshu/meltysynth
Dependencies #
This package has no dependencies.
Maintanence #
This project was specifically designed to not require maintanence, in large part by not having any dependencies. Apart from breaking changes to the Dart language (rare), it should be solid code that works for decades. It will work on any Dart SDK sdk>=2.12 && sdk<4.0 indefinitely.
This package was written against Dart SDK 2.16.1.
Example #
Synthesize a simple chord:
// Necessary Imports
import 'package:dart_melty_soundfont/dart_melty_soundfont.dart';
import 'package:flutter/services.dart' show rootBundle;
// Create the synthesizer.
ByteData bytes = await rootBundle.load('assets/akai_steinway.sf2');
Synthesizer synth = Synthesizer.loadByteData(bytes,
SynthesizerSettings(
sampleRate: 44100,
blockSize: 64,
maximumPolyphony: 64,
enableReverbAndChorus: true,
));
// print available presets
List<Preset> p = synth.soundFont.presets;
for (int i = 0; i < p.length; i++) {
String instrumentName = p[i].regions.isNotEmpty ? p[i].regions[0].instrument.name : "N/A";
print('[preset $i] name: ${p[i].name} instrument: $instrumentName');
}
// select first preset (aka instrument)
synth.selectPreset(channel: 0, preset: 0);
// Turn on some notes
synth.noteOn(channel: 0, key: 72, velocity: 120);
synth.noteOn(channel: 0, key: 76, velocity: 120);
synth.noteOn(channel: 0, key: 79, velocity: 120);
synth.noteOn(channel: 0, key: 82, velocity: 120);
// Render the waveform (3 seconds)
ArrayInt16 buf16 = ArrayInt16.zeros(numShorts: 44100 * 3);
synth.renderMonoInt16(buf16);
Playing Sound #
See the Example App for a raw_sound + dart_melty_soundfont example.
This library does not audibly make sound, it only generates the PCM waveform.
To actually hear something, you need to pass the generated PCM waveform to your device's speakers. I recommend using flutter_pcm_sound or Web Audio for that task, depending on your platform.
Features #
-
No memory allocation in the rendering process.
-
Wave synthesis
- ✅ SoundFont reader
- ✅ Waveform generator
- ✅ Envelope generator
- ✅ Low-pass filter
- ✅ Vibrato LFO
- ✅ Modulation LFO
-
MIDI message processing
- ✅ Note on/off
- ✅ Bank selection
- ✅ Modulation
- ✅ Volume control
- ✅ Pan
- ✅ Expression
- ✅ Hold pedal
- ✅ Program change
- ✅ Pitch bend
- ✅ Tuning
-
Effects
- ✅ Reverb
- ✅ Chorus
-
Other things
- ✅ Loop extension support
- ✅ Performace optimization
Todo #
- MIDI file support.
Feel free to port MIDI file support to Dart and make a pull request.
Its usage would look like this when implemented:
// Create the synthesizer.
var sampleRate = 44100;
var synthesizer = new Synthesizer("TimGM6mb.sf2", sampleRate);
// Read the MIDI file.
var midiFile = MidiFile("flourish.mid");
var sequencer = MidiFileSequencer(synthesizer);
sequencer.play(midiFile, false);
// Render the waveform (3 seconds)
ArrayInt16 buf16 = ArrayInt16.zeros(numShorts: 44100 * 3);
sequencer.renderMonoInt16(buf16);
License #
DartMeltySoundFont is available under the MIT license.
References #
-
SoundFont® Technical Specification
http://www.synthfont.com/SFSPEC21.PDF -
Polyphone Soundfont Editor
Some of the test cases were generated with Polyphone.
https://www.polyphone-soundfonts.com/ -
Freeverb by Jezar at Dreampoint
The implementation of the reverb effect is based on Freeverb.
https://music.columbia.edu/pipermail/music-dsp/2001-October/045433.html