如何在Swift中流式传输MP3网址(iOS)？

audio.scheduleFile(NSBundle.mainBundle().URLForResource(“Moon River”,withExtension：“mp3”)！)
它将正确播放本地文件.现在我希望能够流式传输非本地网址.

我需要做什么才能让我流式传输MP3网址？

class Audio: NSObject {
    var graph: AUGraph
    var filePlayerAU: AudioUnit
    var filePlayerNode: AUNode
    var outputAU: AudioUnit
    var fileID: AudioFileID
    var currentFrame: Int64

    override init () {
        graph = AUGraph()
        filePlayerAU = AudioUnit()
        filePlayerNode = AUNode()
        outputAU = AudioUnit()
        fileID = AudioFileID()
        currentFrame = 0

        super.init()

        NewAUGraph(&graph)

        // Add file player node
        var cd = AudioComponentDescription(componentType: OSType(kAudioUnitType_Generator),componentSubType: OSType(kAudioUnitSubType_AudioFilePlayer),componentManufacturer: OSType(kAudioUnitManufacturer_Apple),componentFlags: 0,componentFlagsMask: 0)
        AUGraphAddNode(graph,&cd,&filePlayerNode)

        // Add output node
        var outputNode = AUNode()

        cd.componentType = OSType(kAudioUnitType_Output)
        cd.componentSubType = OSType(kAudioUnitSubType_RemoteIO)
        AUGraphAddNode(graph,&outputNode)

        // Graph must be opened before we can get node info!
        AUGraphOpen(graph)
        AUGraphNodeInfo(graph,filePlayerNode,nil,&filePlayerAU)
        AUGraphNodeInfo(graph,outputNode,&outputAU)


        AUGraphConnectNodeInput(graph,0)
        AUGraphInitialize(graph)

        registerCallbackForAU(filePlayerAU,nil)
    }

    func scheduleFile(url: NSURL) {
        AudioFileOpenURL(url,1,&fileID)

        // Step 1: schedule the file(s)
        // kAudioUnitProperty_ScheduledFileIDs takes an array of AudioFileIDs
        var filesToSchedule = [fileID]
        AudioUnitSetProperty(filePlayerAU,AudioUnitPropertyID(kAudioUnitProperty_ScheduledFileIDs),AudioUnitScope(kAudioUnitScope_Global),filesToSchedule,UInt32(sizeof(AudioFileID)))
    }

    func scheduleRegion() {
        // Step 2: Schedule the regions of the file(s) to play
        // Swift forces us to fill out the structs completely,even if they are not used
        let smpteTime = SMPTETime(mSubframes: 0,mSubframeDivisor: 0,mCounter: 0,mType: 0,mFlags: 0,mHours: 0,mMinutes: 0,mSeconds: 0,mFrames: 0)

        var timeStamp = AudioTimeStamp(mSampleTime: 0,mHostTime: 0,mRateScalar: 0,mWordClockTime: 0,mSMPTETime: smpteTime,mFlags: UInt32(kAudioTimeStampSampleTimeValid),mReserved: 0)

        var region = ScheduledAudioFileRegion()
        region.mTimeStamp = timeStamp
        region.mCompletionProc = nil
        region.mCompletionProcUserData = nil
        region.mAudioFile = fileID
        region.mLoopCount = 0
        region.mStartFrame = currentFrame
        region.mFramesToPlay = UInt32.max

        AudioUnitSetProperty(filePlayerAU,AudioUnitPropertyID(kAudioUnitProperty_ScheduledFileRegion),&region,UInt32(sizeof(ScheduledAudioFileRegion)))

        // Step 3: Prime the file player
        var primeFrames: UInt32 = 0
        AudioUnitSetProperty(filePlayerAU,AudioUnitPropertyID(kAudioUnitProperty_ScheduledFilePrime),&primeFrames,UInt32(sizeof(UInt32)))

        // Step 4: Schedule the start time (-1 = now)
        timeStamp.mSampleTime = -1
        AudioUnitSetProperty(filePlayerAU,AudioUnitPropertyID(kAudioUnitProperty_ScheduleStartTimeStamp),&timeStamp,UInt32(sizeof(AudioTimeStamp)))
    }
}