iphone - 更改 "sounder"的音频音高

Question

编辑:在底部添加了新代码。

我在编码方面还很陌生，所以我首先创建了一个音板应用程序。我已经能够使用“速率”命令来减慢或加快音频，但现在我也想改变音调。理想情况下，我想要两个开关。一种加速音频并提高音调，一种减慢和降低音调，如果它们都关闭，则播放正常。下面是我的代码，它适用于除改变音高之外的所有内容。非常感谢任何输入。作为引用，sass 很慢，chip 很快。

import UIKit
import AVFoundation

var Sounder1 = AVAudioPlayer()
var Sounder2 = AVAudioPlayer()

let sassFloat: Float = 0.5
let myInt = Int(sassFloat)

let chipFloat: Float = 3.0
let myInt2 = Int(chipFloat)

class ViewController: UIViewController {

@IBOutlet weak var sassSwitch: UISwitch!

@IBOutlet weak var chipSwitch: UISwitch!

override func viewDidLoad() {
    super.viewDidLoad()

    do {
        Sounder1 = try AVAudioPlayer(contentsOf: URL.init(fileURLWithPath: Bundle.main.path(forResource: "Sound1", ofType: "mp3")!))
        Sounder1.prepareToPlay()
        Sounder1.enableRate = true
    }catch{

    }

    do {
        Sounder2 = try AVAudioPlayer(contentsOf: URL.init(fileURLWithPath: Bundle.main.path(forResource: "Sound2", ofType: "wav")!))
        Sounder2.prepareToPlay()
        Sounder2.enableRate = true
    }catch{

    }
    // Do any additional setup after loading the view, typically from a nib.
}

@IBAction func sassAction(_ sender: UISwitch) {
    chipSwitch.setOn(false, animated: true)
}

@IBAction func chipAction(_ sender: UISwitch) {
    sassSwitch.setOn(false, animated: true)
}

@IBAction func play(_ sender: Any) {
    if sassSwitch.isOn {
        Sounder1.rate = sassFloat
        Sounder1.play()
    } else if chipSwitch.isOn {
        Sounder1.rate = chipFloat
        Sounder1.play()
    } else {
        Sounder1.rate = 1.0
        Sounder1.play()
    }

}

@IBAction func play2(_ sender: Any) {
    if sassSwitch.isOn {
        Sounder2.rate = sassFloat
        Sounder2.play()
    } else if chipSwitch.isOn {
        Sounder2.rate = chipFloat
        Sounder2.play()
    } else {
        Sounder2.rate = 1.0
        Sounder2.play()
    }
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

这是我根据@ericl 的建议编写的新代码。我仍然需要 reset() 音频引擎，但我也有几个问题。1) if else if else 语句在这种情况下真的有效吗？2) 我在哪里添加 reset() 语句。3) 是否需要在每次播放声音后分离节点？还是只是重置？

class ViewController: UIViewController {

@IBOutlet weak var sassSwitch: UISwitch!
@IBOutlet weak var chipSwitch: UISwitch!

@IBAction func sassAction(_ sender: UISwitch) {
    chipSwitch.setOn(false, animated: true)
}
@IBAction func chipSwitch(_ sender: UISwitch) {
    sassSwitch.setOn(false, animated: true)
}


///Playback Engine
private let audioEngine = AVAudioEngine()

///Player's Nodes
private let pitchPlayer = AVAudioPlayerNode()
private let timePitch = AVAudioUnitTimePitch()

///Audio Files to be played
private var audioFile1 = AVAudioFile()
private var audioFile2 = AVAudioFile()

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    if let filePath = Bundle.main.path(forResource: "PeteNope", ofType:
        "mp3") {
        let filePathURL = URL(fileURLWithPath: filePath)

        setPlayerFile(filePathURL)

    }

    if let filePath2 = Bundle.main.path(forResource: "Law_WOW", ofType:
        "mp3") {
        let filePath2URL = URL(fileURLWithPath: filePath2)

        setPlayerFile2(filePath2URL)

    }
}

private func setPlayerFile(_ fileURL: URL) {
    do {
        let file = try AVAudioFile(forReading: fileURL)

        self.audioFile1 = file


    } catch {
        fatalError("Could not create AVAudioFile instance. error: \(error).")
    }
}

private func setPlayerFile2(_ fileURL: URL) {
    do {
        let file = try AVAudioFile(forReading: fileURL)

        self.audioFile2 = file


    } catch {
        fatalError("Could not create AVAudioFile instance. error: \(error).")
    }
}


@IBAction func sound1Play(_ sender: UIButton) {
    if sassSwitch.isOn {
        timePitch.pitch = -300
        timePitch.rate = 0.5
        audioEngine.attach(pitchPlayer)
        audioEngine.attach(timePitch)

        audioEngine.connect(pitchPlayer, to: timePitch, format: audioFile1.processingFormat)
        audioEngine.connect(timePitch, to: audioEngine.outputNode, format: audioFile1.processingFormat)
        pitchPlayer.scheduleFile(audioFile1, at: nil, completionHandler: nil)

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

        pitchPlayer.play()

    } else if chipSwitch.isOn {
        timePitch.pitch = +500
        timePitch.rate = 2.0
        audioEngine.attach(pitchPlayer)
        audioEngine.attach(timePitch)

        audioEngine.connect(pitchPlayer, to: timePitch, format: audioFile1.processingFormat)
        audioEngine.connect(timePitch, to: audioEngine.outputNode, format: audioFile1.processingFormat)
        pitchPlayer.scheduleFile(audioFile1, at: nil, completionHandler: nil)

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

        pitchPlayer.play()

    } else {
        timePitch.pitch = +0
        timePitch.rate = 1.0
        audioEngine.attach(pitchPlayer)
        audioEngine.attach(timePitch)

        audioEngine.connect(pitchPlayer, to: timePitch, format: audioFile1.processingFormat)
        audioEngine.connect(timePitch, to: audioEngine.outputNode, format: audioFile1.processingFormat)
        pitchPlayer.scheduleFile(audioFile1, at: nil, completionHandler: nil)

        // Start the engine.
        do {
            try audioEngine.start()
        } catch {
            fatalError("Could not start engine. error: \(error).")
        }
        pitchPlayer.play()
    }

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

Answer 1

您将使用 AVAudioEngine 将 AVAudioPlayerNode 附加到 AVAudioUnitTimePitch 效果。我检查了苹果的 AudioUnitV3Example示例代码并从中拼凑出一个工作示例。你会想要实现更多的状态和错误处理，你可以在那里找到。无论如何，这里是:

在类的顶部定义一些私有(private)变量:

   /// Playback engine.
    private let audioEngine = AVAudioEngine()

    /// Engine's player node.
    private let pitchPlayer = AVAudioPlayerNode()
    private let timePitch = AVAudioUnitTimePitch()

    /// File to play.
    private var audioFile: AVAudioFile?

检查有效的音频文件:

     override func viewDidLoad() {
         super.viewDidLoad()

     if let filePath = Bundle.main.path(forResource: "Sound1", ofType: 
 "mp3") {
         let filePathURL = URL(fileURLWithPath: filePath)

         setPlayerFile(filePathURL)

         }
     }

     private func setPlayerFile(_ fileURL: URL) {
         do {
             let file = try AVAudioFile(forReading: fileURL)

             self.audioFile = file


         } catch {
             fatalError("Could not create AVAudioFile instance. error: \(error).")
         }
     }

     @IBAction func verySlowPlayback(sender: UIButton) {


    timePitch.pitch = -300
    timePitch.rate = 0.5
    audioEngine.attach(pitchPlayer)
    audioEngine.attach(timePitch)

    audioEngine.connect(pitchPlayer, to: timePitch, format: audioFile?.processingFormat)
    audioEngine.connect(timePitch, to: audioEngine.outputNode, format: audioFile?.processingFormat)
    pitchPlayer.scheduleFile(audioFile!, at: nil, completionHandler: nil)

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

    pitchPlayer.play()

}