多个声道播放多个WAV AVAudioEngine

我有15个WAV文件，需要按顺序播放各个频道。我开始尝试使用左/右立体声分离处理两个文件。多个声道播放多个WAV AVAudioEngine

我正在创建一个音频引擎，一个混音器和两个AVAudioPlayerNodes。音频文件是单声道的，我试图从PlayerA得到文件出来左边的频道，并从PlayerB的文件出来右边的频道。我无法理解的是AudioUnitSetProperty是如何工作的。它似乎只涉及单个文件，似乎只能有一个每个audioUnit？我想知道是否有一种方法可以将文件与audioUnit关联起来？我似乎无法返回与每个轨道关联的audioUnit对象。

func testCode(){ 

    // get output hardware format 
    let output = engine.outputNode 
    let outputHWFormat = output.outputFormat(forBus: 0) 
    // connect mixer to output 
    let mixer = engine.mainMixerNode 
    engine.connect(mixer, to: output, format: outputHWFormat) 


    //then work on the player end by first attaching the player to the engine 
    engine.attach(playerA) 
    engine.attach(playerB) 


    //find the audiofile 
    guard let audioFileURLA = Bundle.main.url(forResource: "test", withExtension: "wav") else { 
     fatalError("audio file is not in bundle.") 
    } 

    guard let audioFileURLB = Bundle.main.url(forResource: "test2", withExtension: "wav") else { 
     fatalError("audio file is not in bundle.") 
    } 

    var songFileA:AVAudioFile? 
    do { 
     songFileA = try AVAudioFile(forReading: audioFileURLA) 
     print(songFileA!.processingFormat) 

     // connect player to mixer 
     engine.connect(playerA, to: mixer, format: songFileA!.processingFormat) 

    } catch { 
     fatalError("canot create AVAudioFile \(error)") 
    } 


    let channelMap: [Int32] = [0, -1] //play channel in left 


    let propSize: UInt32 = UInt32(channelMap.count) * UInt32(MemoryLayout<sint32>.size) 

    print(propSize) 

    let code: OSStatus = AudioUnitSetProperty((engine.inputNode?.audioUnit)!, 
               kAudioOutputUnitProperty_ChannelMap, 
               kAudioUnitScope_Global, 
               1, 
               channelMap, 
               propSize); 
    print(code) 


    let channelMapB: [Int32] = [-1, 0] //play channel in left 

    var songFileB:AVAudioFile? 
    do { 
     songFileB = try AVAudioFile(forReading: audioFileURLB) 
     print(songFileB!.processingFormat) 

     // connect player to mixer 
     engine.connect(playerB, to: mixer, format: songFileB!.processingFormat) 

    } catch { 
     fatalError("canot create AVAudioFile \(error)") 
    } 

    let codeB: OSStatus = AudioUnitSetProperty((engine.inputNode?.audioUnit)!, 
               kAudioOutputUnitProperty_ChannelMap, 
               kAudioUnitScope_Global, 
               1, 
               channelMapB, 
               propSize); 

    print(codeB) 


    do { 
     try engine.start() 
    } catch { 
     fatalError("Could not start engine. error: \(error).") 
    } 

    playerA.scheduleFile(songFileA!, at: nil) { 
     print("done") 
     self.playerA.play() 
    } 
    playerB.scheduleFile(songFileA!, at: nil) { 
     print("done") 
     self.playerB.play() 
    } 

    playerA.play() 
    playerB.play() 

    print(playerA.isPlaying) 

}

来源

2017-09-04 tsugua

engine.connect（混频器，以：输出，格式：outputHWFormat）

这是没有必要的，混频器将被隐式访问时连接。

至于平移：AudioUnitSetProperty也是没有必要的。 AVAudioPlayerNode符合AVAudioMixing，这样以来有来自玩家下游的混频器节点，所有你需要做的是这样的：

playerA.pan = -1 
playerB.pan = 1

来源

2017-09-05 23:31:52 dave234

感谢您的建议戴夫。我曾经看过泛功能，但我最终试图将15个文件输出到15个独立的频道，因此无法在该应用程序中进行平移。 – tsugua

多个声道播放多个WAV AVAudioEngine

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