Midi Maker

A full implementation of the MIDI file format, implemented in C++. Midi Maker provides classes with respective member functions for each midi command, as well as some useful utility functions. If throughout the usage of this code you need more information on the internals of MIDI, I recommend the following page: MIDI File Format.

Repository Structure

• /src contains the source files required for MIDI file creation.
• /test contains the tests for all functionality. Tests are written using Catch
• /examples contains programs written to give example usages of the library, which, when run, play the resulting midi file.

How To Add Midi Maker To Your Project

To add Midi Maker, simply add the following two files from /src to your project: midi.h and midi.cpp.

How To Use Midi Maker

There are 3 classes of use for creating Midi files. These are:

• MidiHeader - used for MIDI header chunks
• MidiTrack - used for MIDI track chunks
• MidiFile - used to combine chunks into a MIDI file

MidiHeader

Every Midi file needs a Header file. Creating a header is as simple as calling the constructor

Example Usage:

int format = 0; //MIDI format, can be 0, 1 or 2
int tracks = 1; //How many track chunks do we have
int divisions = 4; //defines default unit of delta time
MidiHeader hd(format, tracks, division);

MidiTrack

A MIDI file can have 1 or more track chunks. This is where the musical information is actually stored. To create and add to a track chunk, one just has to create an object of the MidiTrack class, and can then sequentially call whichever commands they wish. You must ensure each track ends with an end of track message however.

Example Usage:

MidiTrack trk;

//meta events
trk.setTempo(0, 50000); //120bpm
trk.programChange(0, 30); //distorted electric guitar
trk.keySignature(0, 0, 0); //C Major

//note sequence
trk.noteOn(0, 0x3C, 0x40);
trk.noteOff(20, 0x3C, 0x40);

trk.noteOn(0, 0x3C, 0x40);
trk.noteOff(20, 0x3C, 0x40);

//and so on...

//end of track
trk.endOfTrack(0);

MidiFile

This class brings together all of your MIDI chunks and dumps it into a file. Since a MIDI file must have at least one Header and Track chunk, one of each are passed into the constructor. Further track chunks can be added using addTrack().

Example usage:

MidiHeader hd(1, 2, 4);

MidiTrack trk1;
//add content to track

MidiTrack trk2;
//add content to track

std::string fileName = "example.mid";

MidiFile midi(fileName, hd, trk1); //add head and first track
midi.addTrack(trk2); //add second track
midi.close(); //close the midi File once finished with it

How To Test Midi Maker

If you wish to run the Catch unit tests, simply compile Midi Maker with alongside the file /test/testMidi.cpp. This should produce an executable which, when run, carries out the unit tests. Individual tests can also be run from this executable. Please see the Catch documentation for details.

Running The Example Code

This code has been developed on a Windows machine. Therefore, in examples, when the file is played using mciSendString, this will not work in any non-Windows machines. If you still want to run these examples, remove the following lines to just generate the .mid file and then you can play the midi file using whatever you have available on your OS:

#include <Windows.h>
#include <MMSystem.h>

//...

mciSendString("play someMidi.mid",nullptr,0,nullptr);
Sleep(5000);