使用 Swift 使用 AVAudioEngine 实时进行音高转换

Posted 2023-02-15

【中文标题】使用 Swift 使用 AVAudioEngine 实时进行音高转换

【英文标题】：Pitch Shifting in Real Time With AVAudioEngine using Swift

【发布时间】：2015-11-24 12:36:11

【问题描述】：

我正在使用 Swift 在 OSX 上开发音频效果应用程序，我对集成音高变换效果很感兴趣。

我想实时将音调上调或下调一个八度。目前我只收到一个干燥的信号。

我不确定这是否可能，我想知道这是否可能，或者任何人可能有任何帮助或建议。

目前与问题相关的代码如下：

import Cocoa
import AVFoundation


class ViewController: NSViewController 
       var engine = AVAudioEngine()
       var timePitch = AVAudioUnitTimePitch()


    override func viewDidLoad() 
         timePitch.pitch = 1200

        // Setup engine and node instances
        var mixer = engine.mainMixerNode
        var input = engine.inputNode
        var output = engine.outputNode
        var format = input.inputFormatForBus(0)
        var error:NSError?

       engine.attachNode(timePitch)

       engine.connect(input, to: timePitch, format: format)
       engine.connect(timePitch, to: output, format: format)

      engine.startAndReturnError(&error)

        super.viewDidLoad()
    

   override var representedObject: AnyObject? 
        didSet 
        // Update the view, if already loaded.
        
    

【参考方案1】：

timePitch.pitch = -500 //Rude man voice
timePitch.rate = 1.5 //In 1.5 times faster

检查this tutorial。和direct link 以获取更多信息的教程示例。

Swift 2.0 示例：

import UIKit
import AVFoundation

class ViewController: UIViewController 

    var engine: AVAudioEngine!
    var player: AVAudioPlayerNode!

    var file = AVAudioFile()

    override func viewDidLoad() 
        super.viewDidLoad()

        engine = AVAudioEngine()
        player = AVAudioPlayerNode()
        player.volume = 1.0

        let path = NSBundle.mainBundle().pathForResource("in", ofType: "caf")!
        let url = NSURL.fileURLWithPath(path)

        let file = try? AVAudioFile(forReading: url)
        let buffer = AVAudioPCMBuffer(PCMFormat: file!.processingFormat, frameCapacity: AVAudioFrameCount(file!.length))
        do 
            try file!.readIntoBuffer(buffer)
         catch _ 
        

        let pitch = AVAudioUnitTimePitch()

        //
        pitch.pitch = -500 //Distortion
        pitch.rate = 1.5 //Voice speed
        //

        engine.attachNode(player)

        engine.attachNode(pitch)

        engine.connect(player, to: pitch, format: buffer.format)

        engine.connect(pitch, to: engine.mainMixerNode, format: buffer.format)
        player.scheduleBuffer(buffer, atTime: nil, options: AVAudioPlayerNodeBufferOptions.Loops, completionHandler: nil)

        engine.prepare()
        do 
            try engine.start()
         catch _ 
        

        player.play()

    

【讨论】：

非常感谢分享。

更改 pitch.rate 时的质量。有什么方法可以在费率变化时保持相同的质量

【参考方案2】：

timePitch.pitch = 1000 //Filtered Voice
timePitch.rate = 1 //Normal rate

【讨论】：

虽然此代码可能会回答问题，但提供有关它如何和/或为什么解决问题的额外上下文将提高​​答案的长期价值。

感谢您的建议@唐老鸭。下次我会记住这一点