如何将pcm数据流封装为wav格式

要将PCM数据流封装为WAV文件格式，需要将PCM数据流保存到WAV文件中，并为WAV文件添加相应的文件头和元数据。WAV文件格式是一种常见的音频文件格式，通常用于存储未经压缩的音频数据。

下面是一个简单的示例代码，演示了如何将PCM数据流封装为WAV文件格式：

public static void pcmToWav(String pcmPath, String wavPath, int sampleRate, int channels, int bitPerSample) {
    FileInputStream pcmInputStream = null;
    FileOutputStream wavOutputStream = null;
    long totalAudioLen, totalDataLen;
    long longSampleRate = sampleRate;
    int byteRate = bitPerSample * channels * (int) (longSampleRate / 8);

    try {
        pcmInputStream = new FileInputStream(new File(pcmPath));
        wavOutputStream = new FileOutputStream(new File(wavPath));

        totalAudioLen = pcmInputStream.getChannel().size();
        totalDataLen = totalAudioLen + 36;

        byte[] data = new byte[1024];
        writeWaveFileHeader(wavOutputStream, totalAudioLen, totalDataLen, longSampleRate, channels, byteRate);

        while (pcmInputStream.read(data) != -1) {
            wavOutputStream.write(data);
        }

        pcmInputStream.close();
        wavOutputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private static void writeWaveFileHeader(
        FileOutputStream outputStream, long totalAudioLen,
        long totalDataLen, long longSampleRate, int channels,
        int byteRate) throws IOException {

    byte[] header = new byte[44];

    header[0] = 'R';  // RIFF/WAVE header
    header[1] = 'I';
    header[2] = 'F';
    header[3] = 'F';
    header[4] = (byte) (totalDataLen & 0xff);
    header[5] = (byte) ((totalDataLen >> 8) & 0xff);
    header[6] = (byte) ((totalDataLen >> 16) & 0xff);
    header[7] = (byte) ((totalDataLen >> 24) & 0xff);
    header[8] = 'W';
    header[9] = 'A';
    header[10] = 'V';
    header[11] = 'E';
    header[12] = 'f';  // 'fmt ' chunk
    header[13] = 'm';
    header[14] = 't';
    header[15] = ' ';
    header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
    header[17] = 0;
    header[18] = 0;
    header[19] = 0;
    header[20] = 1;  // format = 1
    header[21] = 0;
    header[22] = (byte) channels;
    header[23] = 0;
    header[24] = (byte) (longSampleRate & 0xff);
    header[25] = (byte) ((longSampleRate >> 8) & 0xff);
    header[26] = (byte) ((longSampleRate >> 16) & 0xff);
    header[27] = (byte) ((longSampleRate >> 24) & 0xff);
    header[28] = (byte) (byteRate & 0xff);
    header[29] = (byte) ((byteRate >> 8) & 0xff);
    header[30] = (byte) ((byteRate >> 16) & 0xff);
    header[31] = (byte) ((byteRate >> 24) & 0xff);
    header[32] = (byte) (2 * 16 / 8);  // block align
    header[33] = 0;
    header[34] = (byte) bitPerSample;
    header[35] = 0;
    header[36] = 'd';  // data chunk
    header[37] = 'a';
    header[38] = 't';
    header[39] = 'a';
    header[40] = (byte) (totalAudioLen & 0xff);
    header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
    header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
    header[43] = (byte) ((totalAudioLen >> 24) & 0xff);

    outputStream.write(header, 0, 44);
}

在这个示例代码中，我们定义了一个`pcmToWav()`方法，用于将PCM数据流保存为WAV文件。该方法接收三个参数：PCM文件路径、WAV文件路径、采样率、声道数和位宽。在方法中，我们使用FileInputStream读取PCM文件中的数据，并使用FileOutputStream将WAV文件写入磁盘。同时，我们调用了`writeWaveFileHeader()`方法，向WAV文件中添加WAV文件头和元数据。在添加WAV文件头和元数据时，我们需要根据采样率、声道数和位宽计算出相应的文件头和元数据，并将其写入WAV文件中。

通过调用`pcmToWav()`方法，我们可以将PCM数据流保存为WAV文件，并在保存的过程中添加相应的文件头和元数据。