Go-MeltySynth

Go-MeltySynth is a SoundFont synthesizer written in Go, ported from MeltySynth for C#.

Features

• Suitable for both real-time and offline synthesis.
• Support for standard MIDI files.
• No dependencies other than the standard library.

Demo

https://www.youtube.com/watch?v=HLta6pASIFg

Installation

go get github.com/sinshu/go-meltysynth

Examples

An example code to synthesize a simple chord:

// Load the SoundFont.
sf2, _ := os.Open("TimGM6mb.sf2")
soundFont, _ := meltysynth.NewSoundFont(sf2)
sf2.Close()

// Create the synthesizer.
settings := meltysynth.NewSynthesizerSettings(44100)
synthesizer, _ := meltysynth.NewSynthesizer(soundFont, settings)

// Play some notes (middle C, E, G).
synthesizer.NoteOn(0, 60, 100)
synthesizer.NoteOn(0, 64, 100)
synthesizer.NoteOn(0, 67, 100)

// The output buffer (3 seconds).
length := 3 * settings.SampleRate
left := make([]float32, length)
right := make([]float32, length)

// Render the waveform.
synthesizer.Render(left, right)

Another example code to synthesize a MIDI file:

// Load the SoundFont.
sf2, _ := os.Open("TimGM6mb.sf2")
soundFont, _ := meltysynth.NewSoundFont(sf2)
sf2.Close()

// Create the synthesizer.
settings := meltysynth.NewSynthesizerSettings(44100)
synthesizer, _ := meltysynth.NewSynthesizer(soundFont, settings)

// Load the MIDI file.
mid, _ := os.Open("C:\\Windows\\Media\\flourish.mid")
midiFile, _ := meltysynth.NewMidiFile(mid)
mid.Close()

// Create the MIDI sequencer.
sequencer := meltysynth.NewMidiFileSequencer(synthesizer)
sequencer.Play(midiFile, true)

// The output buffer.
length := int(float64(settings.SampleRate) * float64(midiFile.GetLength()) / float64(time.Second))
left := make([]float32, length)
right := make([]float32, length)

// Render the waveform.
sequencer.Render(left, right)

Todo

• Wave synthesis
  • [x] SoundFont reader
  • [x] Waveform generator
  • [x] Envelope generator
  • [x] Low-pass filter
  • [x] Vibrato LFO
  • [x] Modulation LFO
• MIDI message processing
  • [x] Note on/off
  • [x] Bank selection
  • [x] Modulation
  • [x] Volume control
  • [x] Pan
  • [x] Expression
  • [x] Hold pedal
  • [x] Program change
  • [x] Pitch bend
  • [x] Tuning
• Effects
  • [x] Reverb
  • [x] Chorus
• Other things
  • [x] Standard MIDI file support
  • [x] Performace optimization

License

Go-MeltySynth is available under the MIT license.