SimpleSynth

A simple C# library that can read a MIDI file and spit out a WAV file.

Find it on NuGet: https://www.nuget.org/packages/SimpleSynth/

About

I created SimpleSynth so that I would have an easy way to create WAV audio files from MIDI files output by the AbundantMusic.NET project (https://github.com/Connor14/AbundantMusic.NET). I tried to design SimpleSynth with customization and extensibility in mind, so I am hopeful that users of the library will be able to tweak the generated audio to their liking by implementing new Providers or by extending MidiSynth and implementing new synthesizers.

The included BasicSynth synthesizer creates audio using a combination of a sine wave and a square wave and supports basic percussion synthesis.

Features

Beyond synthesizing the notes that make up the harmonies and melodies of MIDI files, SimpleSynth also supports the following:

• Percussion synthesis
  • Percussion instruments are generalized into one of four types (bass, snare, crash, ride) and are synthesized as such.
• Dynamic tempo
  • MIDI files can contain tempo changes and these changes will be reflected in the final audio output.
• NoteOn event Velocity interpretation
  • The Velocity value of a NoteOn MIDI event is used to amplify a note's sound to make it louder or softer when compared to its neighbors. The results might be audible in cases where accents are used, for example.

Samples

Please see the Samples directory for sample audio.

Tools / Libraries

SimpleSynth

• .NET Standard 2.0
• MidiSharp (https://github.com/stephentoub/MidiSharp)
• NWaves (https://github.com/ar1st0crat/NWaves)

DemoProject

• .NET Core 3.1

Getting Started

Create an instance of the MidiInterpretation class and pass it to an instance of the BasicSynth class. Then run the GenerateWAV method. The resulting MemoryStream is your synthesized WAV file. You can save the MemoryStream to disk or consume it in some other way.

using SimpleSynth.EventArguments;
using SimpleSynth.Parameters;
using SimpleSynth.Parsing;
using SimpleSynth.Providers;
using SimpleSynth.Synths;
using System;
using System.IO;
...
using (var stream = File.OpenRead("YourMidiFile.mid"))
{
    // Parse the provided MIDI file.
    var interpretation = new MidiInterpretation(stream, new DefaultNoteSegmentProvider());

    // Create a new synthesizer with default providers.
    var synth = new BasicSynth(interpretation, new DefaultAdsrEnvelopeProvider(AdsrParameters.Short), new DefaultBalanceProvider());

    // Generate the WAV file
    MemoryStream result = synth.GenerateWAV();

    // Write WAV file to disk
    using (var outputStream = File.OpenWrite("YourOutputWave.wav"))
    {
        result.CopyTo(outputStream);
    }

    result.Dispose();
}

See DemoProject for a more detailed example.

License Information

MidiSharp

MidiSharp is listed under the MIT license and includes Copyright (c) 2014 Stephen Toub.

NWaves

NWaves is listed under the MIT license and includes Copyright (c) 2017 Tim.

Future Development

I would like to implement more synths for a wider range of sounds. Maybe even a SoundFont synth.

I would like to improve the efficiency of the synthesis where I can.

I would like to implement "on-line" / realtime synthesis and playback for MIDI files.