read/write audio file

audio.swift

let musicURL = try! FileManager.default.url(for: .musicDirectory, in: .userDomainMask, appropriateFor: nil, create: false)

let source = musicURL.appendingPathComponent("錄音/原始.wav")
let input = try! AVAudioFile(forReading: source)

let format = input.fileFormat
let destination = musicURL.appendingPathComponent("錄音/複製.wav")
let output = try! AVAudioFile(forWriting: destination, settings: format.settings, commonFormat: format.commonFormat, interleaved: format.isInterleaved)

while input.framePosition < input.length {
    let capacity = min(input.length - input.framePosition, 1024)
    var buffer = AVAudioPCMBuffer(pcmFormat: input.fileFormat, frameCapacity: AVAudioFrameCount(capacity))!
    try! input.read(into: buffer)
    
    var data = [Float](repeating: 0, count: Int(capacity))
    data.withUnsafeMutableBufferPointer{
        let p = buffer.floatChannelData!.pointee
        $0.baseAddress?.initialize(from: p, count: Int(capacity))
    }
    
    buffer = AVAudioPCMBuffer(pcmFormat: output.fileFormat, frameCapacity: UInt32(capacity))!
    buffer.floatChannelData?.pointee.update(from: data, count: Int(capacity))
    buffer.frameLength = AVAudioFrameCount(capacity)
    try! output.write(from: buffer)
}