读取AVAudioFile缓冲区时崩溃创建Swift波形

Question

我一直在AVAudioPlayer中工作并画波浪。我正在AudioArmada Pods的帮助下使用AudioArmada Github吊舱绘制波浪。但是在某些情况下，AVAudioFile在读取缓冲时间时崩溃。

以下代码：

public func openFile(_ file: URL) {
    let audioFile = try! AVAudioFile(forReading: file)
    // specify the format we WANT for the buffer
    let format = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: audioFile.fileFormat.sampleRate, channels: audioFile.fileFormat.channelCount, interleaved: false)
    // initialize and fill the buffer
    let buffer = AVAudioPCMBuffer(pcmFormat: format!, frameCapacity: UInt32(audioFile.length))
    try! audioFile.read(into: buffer!)
    // copy buffer to readFile struct
    readFile.floatValuesLeft = Array(UnsafeBufferPointer(start: buffer?.floatChannelData?[0], count:Int(buffer!.frameLength)))
    readFile.populated = true
    reload(zoomFactor: zoomFactor)
}

public func reload(zoomFactor: Float = 1.0) {
    self.zoomFactor = zoomFactor
    setNeedsDisplay()
}

func drawSoundcloudWaveform(_ rect: CGRect) {
  let path = UIBezierPath()
  path.move(to: CGPoint(x: 0.0, y: rect.height/2))
  var index = 0
  while index < readFile.leftPoints.count {
  let point = readFile.leftPoints[index]
  let drawFrom = CGPoint(x: point.x, y: path.currentPoint.y)
  path.move(to: drawFrom)
  let drawPointBottom = CGPoint(x: point.x, y: path.currentPoint.y + (point.y))
   path.addLine(to: drawPointBottom)
   path.addLine(to: CGPoint(x: drawPointBottom.x + pixelWidth, y: drawPointBottom.y))
   path.addLine(to: CGPoint(x: drawFrom.x + pixelWidth, y: drawFrom.y))
   path.close()
   path.move(to: drawFrom)
   let drawPointTop = CGPoint(x: point.x, y: path.currentPoint.y - (point.y))
   path.addLine(to: drawPointTop)
   path.addLine(to: CGPoint(x: drawPointTop.x + pixelWidth, y: drawPointTop.y))
   path.addLine(to: CGPoint(x: drawFrom.x + pixelWidth, y: drawFrom.y))
   path.close()
   index = index + Int(pixelWidth) + Int(pixelSpacing)
   }
    UIColor(red:0.21, green:0.77, blue:0.78, alpha:1.0).set()
    path.stroke()
    path.fill()
}

以下案例：

1. 运行案例：

   guard let file = Bundle.main.url(forResource: "Beat9", withExtension: ".mp3") else { return }
   openFile(file) 
   
   AVAudioPCMBuffer Output:  AVAudioPCMBuffer@0x6000005c9300: 0/35864064 bytes
   

波形屏幕截图：

1. 崩溃案例：

   guard let file = Bundle.main.url(forResource: "IshqMubarak", withExtension: ".mp3") else { return }
   openFile(file)
   
   AVAudioPCMBuffer Output: AVAudioPCMBuffer@0x600003eb1180: 0/0 bytes // i m confused why show zero bytes buffer 
   

  

错误：致命错误：“尝试！”表达式意外引发错误：Foundation._GenericObjCError.nilError：文件/Users/apple/Desktop/AudioArmada-90f214d3d9483e817cdb1396e08f8f626a7be821/AudioArmada/Classes/WaveformZoomable.swift，第63行

问题：如何解决此问题以及为什么有时会崩溃？

任何帮助将不胜感激。

谢谢。

Answer 1

看到错误，它在 AudioArmada 的WaveformZoomable.swift的第63行崩溃，其中HashSet用于 nil 对象。

AVAudioFile引发（与第56行相同）：

try!

---

您可以使用

• func read(into buffer: AVAudioPCMBuffer) throws 暂时摆脱崩溃
• 或try? try找出无法阅读的原因
• 并在AudioArmada上提交问题