Hearn.Midi 1.0.0

Hearn.Midi

A .net implementation of the MIDI file standard without using Windows API wrappers.

Standard MIDI Files Specification RP-001_v1-0_Standard_MIDI_Files_Specification_96-1-4.pdf

MidiStreamWriter

A fluent stream writer to create .mid files.

Call .WriteHeader() and specify the file format (single or multi track), and the number of tracks.

For each track wrap the content between .WriteStartTrack() and .WriteEndTrack().

Unless overridden using .WriteTimeSignature() and .WriteTempo tracks will be 4:4 time 120bpm.

Notes are created using .WriteNote() supplying

• channel - One of 16 channels (zero based) [0..15]. Channel 10 [9] is reserved for percussion.
• note - The value MidiNoteNumbers.C4 is Middle C
• velocity- Soft to loud (0..127)
• duration - length of the note (NoteDurations.QuarterNote, NoteDurations.Crotchet and 96 are all equivalent)

As more notes are written they are stacked at the same starting point.

Notes are turned off by calling .Tick() to progress through the track as the NoteDurations value for the note is ticked over by the NoteDurations value for the tick.

.WritePercussion() writes to channel 10 using the note mappings from the Percussion enum.

Example Usage

The following example will write a C Major I-V-vi-IV chord progression.

var midiStream = new FileStream("music.mid", FileMode.OpenOrCreate);

using (var midiStreamWriter = new MidiStreamWriter(midiStream))
{
    midiStreamWriter
        .WriteHeader(Formats.MultiSimultaneousTracks, 2);

    midiStreamWriter
        .WriteStartTrack()
            .WriteTimeSignature(4, 4)
            .WriteTempo(120)
            .WriteString(StringTypes.TrackName, "Example Track")
        .WriteEndTrack();
        
    midiStreamWriter
        .WriteStartTrack()
            .WriteNote(0, MidiNoteNumbers.C4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.E4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.G4, 127, NoteDurations.WholeNote)
            .Tick(NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.G4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.B4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.D5, 127, NoteDurations.WholeNote)
            .Tick(NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.A4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.C5, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.E5, 127, NoteDurations.WholeNote)
            .Tick(NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.F4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.A4, 127, NoteDurations.WholeNote)
            .WriteNote(0, MidiNoteNumbers.C5, 127, NoteDurations.WholeNote)
            .Tick(NoteDurations.WholeNote)
        .WriteEndTrack();
}

Convenience methods

Multiple notes can be written using .WriteNotes()

The following example will write a C Major chord with a single method call

midiStreamWriter.WriteNotes(0, new List<MidiNote>()
{
    new MidiNote() { Note = MidiNoteNumbers.C4, Velocity = 127, Duration = NoteDurations.WholeNote },
    new MidiNote() { Note = MidiNoteNumbers.E4, Velocity = 127, Duration = NoteDurations.WholeNote },
    new MidiNote() { Note = MidiNoteNumbers.G4, Velocity = 127, Duration = NoteDurations.WholeNote }
});

Notes can be written and automatically ticked over using .WriteNoteAndTick().

The following example will write a C Major arpeggio over a single (4:4) bar

midiStreamWriter
    .WriteNoteAndTick(0, MidiNoteNumbers.C4, 127, NoteDurations.QuarterNote)
    .WriteNoteAndTick(0, MidiNoteNumbers.E4, 127, NoteDurations.QuarterNote)
    .WriteNoteAndTick(0, MidiNoteNumbers.G4, 127, NoteDurations.QuarterNote)
    .WriteNoteAndTick(0, MidiNoteNumbers.C5, 127, NoteDurations.QuarterNote);

Worked example

The project Hearn.Midi.Example is an example console application that creates an example .mid (saved to bin folder) file with 5 tracks

1. Track meta data (3:4 time, 104 bpm & track name)
2. Right hand piano
3. Left hand piano
4. Chords
5. Percussion

Known issues

The "running status" concept in MIDI files is not strictly adhered to. Extra (but passive) note on (0x90) and note off (0x80) events are written.