Question

我目前有一个使用AKKeyboard使用振荡器创建声音的应用程序。每当弹奏键盘时，我也会获取MIDI数据。我想做的是根据收到的MIDI数据创建AKSequence。

任何建议或指示都将不胜感激，谢谢。

这是我的部分代码：

var bank = AKOscillatorBank()
var midi: AKMIDI!
let sequencer = AKSequencer()
let sequenceLength = AKDuration(beats: 8.0)

func configureBank() {
    AudioKit.output = bank

    do {
        try AudioKit.start()
    } catch {
        AKLog("AudioKit couldn't be started")
    }

    midi = AudioKit.midi
    midi.addListener(self)
    midi.openInput()
}

// AKKeyboard Protocol methods
func noteOn(note: MIDINoteNumber) {
    let event = AKMIDIEvent(noteOn: note, velocity: 80, channel: 5)
    midi.sendEvent(event)
    bank.play(noteNumber: note, velocity: 100)
}

func noteOff(note: MIDINoteNumber) {
    let event = AKMIDIEvent(noteOff: note, velocity: 0, channel: 5)
    midi.sendEvent(event)
    bank.stop(noteNumber: note)
}

// AKMIDIListener Protocol methods..
func receivedMIDINoteOff(noteNumber: MIDINoteNumber, velocity: MIDIVelocity, channel: MIDIChannel) {
    print("ReceivedMIDINoteOff: \(noteNumber), velocity: \(velocity), channel: \(channel)")
}

Answer 1

您实际上并不需要直接从AKMIDIEvents构建序列。只需在调用AKKeyboardView的noteOn和noteOff方法时查询序列的currentPosition，然后根据此方法将事件以编程方式添加到音序器轨道中即可。

此过程基本上与此相同（当然要减去最后一步）：https://stackoverflow.com/a/50071028/2717159

编辑-获取noteOn和noteOff时间以及持续时间：

// store notes and times in a dictionary:
var noteDict = [MIDINoteNumber: MIDITimeStamp]()

// when you get a noteOn, note the time
noteDict[currentMIDINote] = seq.currentPosition.beats

// when you get a noteOff
let endTime = seq.currentPosition.beats
if let startTime = noteDict[currentMIDINote] {
    let durationInBeats = endTime - startTime
    // use the startTime, duration and currentMIDINote to add event to track
    noteDict[currentMIDINote] = nil
}

Swift-AudioKit AKMidi到AKSequencer

1 个答案: