SwiftでWAV形式の音声ファイルをInt16の配列として読み込む

read_wav.swift

import AVFoundation

func readWavFile(_ path: String) -> [[Int16]]? {
    guard let url = URL(string: path) else {
        return nil
    }
    guard let audio = try? AVAudioFile(forReading: url, commonFormat: .pcmFormatInt16, interleaved: false) else {
        return nil
    }
    guard let buffer = AVAudioPCMBuffer(pcmFormat: audio.processingFormat, frameCapacity: AVAudioFrameCount(audio.length)) else {
        return nil
    }
    do {
        try audio.read(into: buffer)
    } catch {
        return nil
    }
    guard let int16ChannelData = buffer.int16ChannelData else {
        return nil
    }

    var channelData = [[Int16]]()

    for i in 0 ..< Int(audio.processingFormat.channelCount) {
        channelData.append(Array(UnsafeBufferPointer(start: int16ChannelData[i], count: Int(buffer.frameLength))))
    }

    return channelData
}

func printSignal(_ path: String) {
    guard let signal = readWavFile(path) else {
        return
    }
    if signal.count < 2 {
        return
    }

    print("Left\tRight")

    for i in 0 ..< signal[0].count {
        print(String(format: "%d\t%d", signal[0][i], signal[1][i]))
    }
}

printSignal("/tmp/music.wav")