portmidi
Want to output to an MIDI device or listen your MIDI device as an input? This package contains Go bindings for PortMidi. libportmidi (v. 217) is required as a dependency, it's available via apt-get and brew.
apt-get install libportmidi-dev
# or
brew install portmidi
Or, alternatively you can download the source and build it by yourself. See the instructions on PortMidi homepage.
In order to start, go get this repository:
go get github.com/rakyll/portmidi
Usage
Initialize
portmidi.Initialize()
About MIDI Devices
portmidi.CountDevices() // returns the number of MIDI devices
portmidi.Info(deviceID) // returns info about a MIDI device
portmidi.DefaultInputDeviceID() // returns the ID of the system default input
portmidi.DefaultOutputDeviceID() // returns the ID of the system default output
Write to a MIDI Device
out, err := portmidi.NewOutputStream(deviceID, 1024, 0)
if err != nil {
log.Fatal(err)
}
// note on events to play C major chord
out.WriteShort(0x90, 60, 100)
out.WriteShort(0x90, 64, 100)
out.WriteShort(0x90, 67, 100)
// notes will be sustained for 2 seconds
time.Sleep(2 * time.Second)
// note off events
out.WriteShort(0x80, 60, 100)
out.WriteShort(0x80, 64, 100)
out.WriteShort(0x80, 67, 100)
out.Close()
Read from a MIDI Device
in, err := portmidi.NewInputStream(deviceID, 1024)
if err != nil {
log.Fatal(err)
}
defer in.Close()
events, err := in.Read(1024)
if err != nil {
log.Fatal(err)
}
// alternatively you can filter the input to listen
// only a particular set of channels
in.SetChannelMask(portmidi.Channel(1) | portmidi.Channel.(2))
in.Read(1024) // will retrieve events from channel 1 and 2
// or alternatively listen events
ch := in.Listen()
event := <-ch
Cleanup
Cleanup your input and output streams once you're done. Likely to be called on graceful termination.
portmidi.Terminate()
