Question

为什么这不起作用？如果我不能让AUGraph产生窦音并且它有效。但是当我将AUGraph添加到声音库时，它并没有发出声音。

func play() {
    var status = OSStatus(noErr)


    status = NewMusicPlayer(&musicPlayer)
    if status != OSStatus(noErr) {
        println("bad status \(status) creating player")
        displayStatus(status)
        return
    }

    status = MusicPlayerSetSequence(musicPlayer, self.musicSequence)
    if status != OSStatus(noErr) {
        displayStatus(status)
        println("setting sequence")
        return
    }

    status = MusicPlayerPreroll(musicPlayer)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

    status = MusicPlayerStart(musicPlayer)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

直到这里它工作正常。之后不是。

    status = NewAUGraph(&self.processingGraph)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

    status = MusicSequenceSetAUGraph(self.musicSequence, self.processingGraph)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

    var samplerNode = AUNode()
    var ioNode = AUNode()

    var cd:AudioComponentDescription = AudioComponentDescription(
        componentType: OSType(kAudioUnitType_MusicDevice),
        componentSubType: OSType(kAudioUnitSubType_Sampler),
        componentManufacturer: OSType(kAudioUnitManufacturer_Apple),
        componentFlags: 0,
        componentFlagsMask: 0)
    status = AUGraphAddNode(self.processingGraph, &cd, &samplerNode)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

    var ioUnitDescription:AudioComponentDescription = AudioComponentDescription(
        componentType: OSType(kAudioUnitType_Output),
        componentSubType: OSType(kAudioUnitSubType_RemoteIO),
        componentManufacturer: OSType(kAudioUnitManufacturer_Apple),
        componentFlags: 0,
        componentFlagsMask: 0)
    status = AUGraphAddNode(self.processingGraph, &ioUnitDescription, &ioNode)
    if status != OSStatus(noErr) {
        displayStatus(status)
        return
    }

    loadSF2Preset(0)



}
func loadSF2Preset(preset:UInt8)  {
    if let bankURL = NSBundle.mainBundle().URLForResource("gs_instruments", withExtension: "dls") {
        var instdata = AUSamplerInstrumentData(fileURL: Unmanaged.passUnretained(bankURL),
            instrumentType: UInt8(kInstrumentType_DLSPreset),
            bankMSB: UInt8(kAUSampler_DefaultMelodicBankMSB),
            bankLSB: UInt8(kAUSampler_DefaultBankLSB),
            presetID: preset)

        var status = AudioUnitSetProperty(
            self.samplerUnit,
            UInt32(kAUSamplerProperty_LoadInstrument),
            UInt32(kAudioUnitScope_Global),
            0,
            &instdata,
            UInt32(sizeof(AUSamplerInstrumentData)))
        //CheckError(status)
    }
}

Answer 1

前段时间我发布了一篇关于如何做到这一点的广泛blog post。有一个有效的github项目。

Swift Midi Soundbank不上场

1 个答案: