java - 比较字节时，提取的音频样本是否应包含在其原始源中？

Question

假设我有一个包含以下内容的音频wav文件:

+-----------+----------------------------------------+
| meta data | 'Audio recognition sometimes is trick' |.wav
+-----------+----------------------------------------+

现在，考虑以Audacity打开此音频，并根据波形图提取并有时将“有时”一词保存在另一个文件中。

+-----------+-------------+
| meta data | 'sometimes' |.wav
+-----------+-------------+

然后，我使用此Java代码仅从两个文件中获取音频数据:

    //...
    Path source = Paths.get("source.wav");
    Path sample = Paths.get("sometimes.wav");
    int index = compare(transform(source), transform(sample));
    System.out.println("Shouldn't I be greater than -1!? " + (index > -1));
    //...

    private int compare(int[] source, int[] sample) throws IOException {
        return Collections.indexOfSubList(Arrays.asList(source), Arrays.asList(sample));
    }

    private int[] transform(Path audio) throws IOException, UnsupportedAudioFileException {
    try (AudioInputStream ais = AudioSystem.getAudioInputStream(
            new ByteArrayInputStream(Files.readAllBytes(audio)))) {

        AudioFormat format = ais.getFormat();
        byte[] audioBytes = new byte[(int) (ais.getFrameLength() * format.getFrameSize())];
        int nlengthInSamples = audioBytes.length / 2;
        int[] audioData = new int[nlengthInSamples];
        for (int i = 0; i < nlengthInSamples; i++) {
            int LSB = audioBytes[2*i]; /* First byte is LSB (low order) */
            int MSB = audioBytes[2*i+1]; /* Second byte is MSB (high order) */
            audioData[i] = (MSB << 8) | (255 & LSB);
        }
        return audioData;
    }
}

现在再来问我一个问题。

考虑到前面提到的提取，此代码是否不应该在原始音频文件中找到“有时”音频数据字节？

我尝试将内容作为字符串进行比较，但是一点都不幸运:

new String(source).contains(new String(sample));

有人可以指出我在这里想念的东西吗？

Answer 1

@菲尔，你就是那个家伙!您的提示使我找到了解决方案!

Audacity样本音频提取以某种不同的方式对样本字节进行编码。

我编写了一个Java程序来识别源音频中的静音，然后拆分了一些
逐字取样；

比较源和匹配的新非听觉采样!

这是新的转换和比较:

private int compare(byte[] captchaData, byte[] sampleData) throws IOException {
    return new String(captchaData).indexOf(new String(sampleData));
}

private byte[] transform(Path audio) throws IOException, UnsupportedAudioFileException {
    AudioInputStream ais = AudioSystem.getAudioInputStream(audio.toFile());
    AudioFormat format = ais.getFormat();
    try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
        int nBufferSize = 1024 * format.getFrameSize();
        byte[] abBuffer = new byte[nBufferSize];
        int nBytesRead;
        while ((nBytesRead = ais.read(abBuffer)) > -1) {
            baos.write(abBuffer, 0, nBytesRead);
        }
        return baos.toByteArray();
    }
}

分离器:

private List<byte[]> split(byte[] audioData) {
    System.out.println(audioData.length);
    List<byte[]> byteList = new ArrayList<>();
    int zeroCounter = 0;
    int lastPos = 0;
    for (int i = 0; i < audioData.length; i++) {
        if (audioData[i] >= -1 && audioData[i] <= 1) {
            zeroCounter++; //too many leading 'zeros' could indicate silence or very low noise...
        } else if (zeroCounter > 0) {
            if (zeroCounter > 2000) {
                int from = lastPos;
                int to = i - (zeroCounter/2);
                byteList.add(
                    Arrays.copyOfRange(
                        audioData,
                        from,
                        to));
                System.out.println("split from: " + from + " to: " + to);
                lastPos = to;
            }
            zeroCounter = 0;
        }
    }
    return byteList;
}

谢谢!