MIDI library optimized for beeing used on embedded devices

This library is in a usable state but not recommended for productive use yet! Most events are not supported yet and the API meight break at any time

• The main target are microcontrollers with very limited ressources

• Robust design / does not behave undefined on malformed or broken MIDI files

• Implementation is done after MIDI 1.0 specification

• Minimum code footprint (configurable by #define)

• Minimum RAM footprint (configurable by #define)

• MIDI file gets not loaded into memory but gets streamed

• A lock free buffer cache which is filled while playing to avoid real time issues on playback

• No use of dynamic memory (malloc and free), just static memory

• Simple abstraction layer, so the library can be ported to any platform easily

• In a later development state MIDI files can also be created. This allows implementing a simple sequencer for example.

• Opening and closing of MIDI files and validation of header.
• Reading of all midi events of any midi0 file (data bytes of some events are ignored)
• Support of running status events
• Non-Blocking MIDI player
• Supported channel events
  • NoteOff
  • NoteOn
  • Control Change
  • Program Change
  • Pitch Bend
• Supported META events
  • End of Track
  • Set Tempo
  • Midi Port
  • All other events are ignored in first iteration and will be supported later

• A cache for the MIDI player to avoid playback timing issues due to slow media access
• Creation of MIDI files
• Support of MIDI 1 files
• MIDI 1 to MIDI 0 converter
• "Compression" - Use running status events plus Note-On with zero velocity for Note-Off

• Only little endian platforms supported

Development and testing is done using Arch Linux. Even this library is targeted for embedded devices it can also be used on non-embedded devices like windows and linux.

Just execute Make

You will find some examples in utils directory:

• dump: dumps all events of a MIDI file
• player: plays a MIDI file using fluidsynth
• gcode: converts a MIDI0 file into gcode, so it can be used for playing music on a CNC mill or 3D printer. (Under development)

To play a MIDI file just execute

bin/player tests/midis/cdefgabc_0.mid

If you get an error like:

Error: cannot open /dev/sequencer

You might need to install fluidsynth first:

sudo pacman -S fluidsynth

sudo pacman -S soundfont-fluid

sudo vim /etc/conf.d/fluidsynth 

Replace the contents by:

SOUND_FONT=/usr/share/soundfonts/FluidR3_GM.sf2
AUDIO_DRIVER=alsa
OTHER_OPTS='-is -m alsa_seq -r 48000'

Create a file at

~/.config/systemd/user/fluidsynth.service

You meight create the systemd/user directories first!

Insert the following content:

[Unit]
Description=FluidSynth launched in server mode
After=sound.target

[Service]
ExecStart=/usr/bin/fluidsynth -a pulseaudio -m alsa_seq -i -l -s -p FluidSynth /usr/share/soundfonts/FluidR3_GM.sf2

[Install]
WantedBy=default.target

Execute:

systemctl --user start fluidsynth.service
systemctl --user enable fluidsynth.service

If /dev/sequencer is not showing up you also meight execute:

sudo modprobe snd-seq-oss

And let is start on each boot by opening

/etc/modules-load.d/modules.conf

and adding:

snd-seq-oss