iOS 在通过 AVAudioUnitTimePitch 播放时调整音高

Posted 2023-02-25

【中文标题】iOS 在通过 AVAudioUnitTimePitch 播放时调整音高

【英文标题】：iOS Adjust Pitch Whilst Playing via AVAudioUnitTimePitch

【发布时间】：2016-05-15 13:10:35

【问题描述】：

我正在尝试获取一些音频，以便能够在播放时调整音高。我对 Swift 和 ios 非常陌生，但我最初的尝试是在播放时更改 timePitchNode.pitch；但是，它不会在播放时更新。我目前的尝试是重置audioEngine，并让它从播放的位置恢复（下图）。如何确定音频当前的位置，以及如何让它从那里恢复？

var audioFile: AVAudioFile?
var audioEngine: AVAudioEngine?
var audioPlayerNode: AVAudioPlayerNode?
var pitch: Int = 1 
    didSet 
        playResumeAudio()
    


…

func playResumeAudio() 
    var currentTime: AVAudioTime? = nil

    if audioPlayerNode != nil 
        let nodeTime = audioPlayerNode!.lastRenderTime!
        currentTime = audioPlayerNode!.playerTimeForNodeTime(nodeTime)
    

    if audioEngine != nil 
        audioEngine!.stop()
        audioEngine!.reset()
    

    audioEngine = AVAudioEngine()

    audioPlayerNode = AVAudioPlayerNode()
    audioEngine!.attachNode(audioPlayerNode!)

    let timePitchNode = AVAudioUnitTimePitch()
    timePitchNode.pitch = Float(pitch * 100)
    timePitchNode.rate = rate
    audioEngine!.attachNode(timePitchNode)

    audioEngine!.connect(audioPlayerNode!, to: timePitchNode, format: nil)
    audioEngine!.connect(timePitchNode, to: audioEngine!.outputNode, format: nil)

    audioPlayerNode!.scheduleFile(audioFile!, atTime: nil, completionHandler: nil)
    let _ = try? audioEngine?.start()

    audioPlayerNode!.playAtTime(currentTime)

【问题讨论】：

“rate”在哪里声明？

只是一个变量

【参考方案1】：

我显然是愚蠢的。您可以在播放期间修改音高，并且它会更新。无需重置任何音频，只需在节点播放时对其进行变异，它就会工作。