Simple-MIDI

Swift classes for simple usage of Core MIDI. Currently only MIDI input is available.

Usage

First, we need to define a MIDIMap with appropriate callbacks. For example, we have some audio unit with a parameter "volume":

let volumeParam = audioUnit.parameterTree?.valueForKey("volume") as! AUParameter

We define CC-map, where we bind CC-number with a parameter. Here we bind an AUParameter with key "volume" to a CC with number 7.

let ccMap: [UInt8 : AUParameter] = [7 : volumeParam] // CC-map is a dictionary of type [CCNum : AUParameter]

Now we initialize MIDIMap with the given CC-map.

// All parameters in the MIDIMap class are optional.
let map = MIDIMap(noteOnOffCallback: nil, sustainPedalCallback: nil, pitchBendCallback: nil, modulationWheelCallback: nil, notificationCallback: nil, ccMapping: ccMap)

We also can define callbacks for another common MIDI messages: Note On/Off, Pitch Bend, Modulation Wheel and MIDI Notifications.

Let's define a callback for the modulation wheel. Our audio unit has a parameter "filter-frequency" with a minimum value of 0 and a maximum value of 1. We're going to change it's value with the modulation wheel.

// get the parameter and initialize a callback
let frequencyParam = audioUnit.parameterTree?.valueForKey("filter-frequency") as! AUParamter
let modulationWheelCallback = {(value: UInt8) in
  frequencyParam.value = AUValue(value)/127
}

// set callback to the MIDIMap
map.modulationWheelCallback = modulationWheelCallback

Now we can initialize MIDIIn.

let midiIn = MIDIIn(clientName: "Here The Name For Your MIDI Client", portName: "Here The Name For Your MIDI Input Port", midiMap: map)

And we can get available MIDI devices now. Let's connect the first one (if any).

if !midiIn.availableDevices.isEmpty {
  midiIn.availableDevices[0].isConnected = true
}

Now we can control the audio unit's parameters with the connected device.