TuningForkMt32

Plays MIDI the way a Roland MT-32 does, through your own installation of the Munt emulator. Nothing of Munt is included: this package loads your copy when a synth is opened.

def deps do
  [
    {:tuning_fork, "~> 0.1.12"},
    {:tuning_fork_mt32, "~> 0.1"}
  ]
end

Setting it up

Set MUNT_LOCATION to a directory holding:

• the Munt library: libmt32emu.dylib (macOS), libmt32emu.so (Linux) or mt32emu.dll (Windows), in the directory itself or in its lib/, and
• the MT-32 ROMs MT32_CONTROL.ROM and MT32_PCM.ROM (or the CM-32L's CM32L_CONTROL.ROM and CM32L_PCM.ROM).

export MUNT_LOCATION=$HOME/munt

Without it, TuningFork.Mt32.available?/0 is false and open/1 returns {:error, :no_munt}; play the same MIDI through TuningFork.Gm instead.

Use

if TuningFork.Mt32.available?() do
  {:ok, synth} = TuningFork.Mt32.open()
  {:ok, sample} = TuningFork.Mt32.render_midi(synth, TuningFork.Midi.read!("song.mid"))
else
  TuningFork.Gm.score(TuningFork.Midi.read!("song.mid"))
end

The result is a TuningFork.Sample: mono PCM at the synth's rate. Save it as a WAV:

TuningFork.Wav.write!("song.wav", sample.pcm, rate: sample.rate, channels: 1)

Or play it through the speaker, with tuning_fork_speaker installed:

{:ok, _stage} = TuningFork.Stage.start_link(sink: TuningFork.Sink.Speaker)
TuningFork.play(TuningFork.Voice.new(sample: sample))

TuningFork.Mt32.render/3 takes raw messages with their times in seconds, sysex included, for music that sends its own patches, and returns stereo PCM at the synth's rate. TuningFork.Mt32.close/1 stops the synth and frees it.

Options and limits

TuningFork.Mt32.open/1 takes:

• :location — the directory holding the Munt library and ROMs, default MUNT_LOCATION
• :rate — the output rate asked of Munt, default 32 000, the MT-32's own

A synth keeps its state between renders: patches sent by sysex stay until it is closed. render_midi/2 adds two seconds after the file's last event for notes to release; render/3 renders exactly the seconds asked for.

Building

Building needs a C compiler only; Munt is found at run time.

Licence

MIT, see LICENSE. Munt is not bundled: it is loaded from your own installation, under its own licence, and the MT-32 and CM-32L ROMs are your own.