Android:使用Raw PCM创建Wave文件，Wave文件无法播放

Question

我已经为波形文件创建了 header ，但是创建的波形文件无法播放。

我用过这个https://ccrma.stanford.edu/courses/422/projects/WaveFormat/作为创建波形标题的引用。

    public void WriteWaveFileHeader() throws IOException {
    File f = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/aaa.wav");
    f.createNewFile();
    FileOutputStream fos = new FileOutputStream(f);
    long longSampleRate=44100;
    int channels= AudioFormat.CHANNEL_IN_MONO;
    long totalAudioLen=fos.getChannel().size();
    long byteRate=(16 * 44100)/8;
    long totalDataLen=totalAudioLen+36;
    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] = 16;  // bits per sample
    header[35] = 0;
    header[36] = 'd';
    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);

    fos.write(header, 0, 44);
    File l = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Notate/" + MainActivity.filepath);
    FileInputStream fis = new FileInputStream(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Notate/" + MainActivity.filepath);
    byte[] buffer = new byte[(int) l.length()];

    int intSize = android.media.AudioTrack.getMinBufferSize(44100, AudioFormat.CHANNEL_OUT_MONO,
            AudioFormat.ENCODING_PCM_16BIT);
    AudioTrack at = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_OUT_MONO,
            AudioFormat.ENCODING_PCM_16BIT, intSize, AudioTrack.MODE_STREAM);
    at.write(buffer,0,(int)l.length());
    fos.write(buffer);
    fos.flush();
    fos.close();


}

Answer 1

尝试以下代码:

private void rawToWave(final File rawFile, final File waveFile) throws IOException {

    byte[] rawData = new byte[(int) rawFile.length()];
    DataInputStream input = null;
    try {
        input = new DataInputStream(new FileInputStream(rawFile));
        input.read(rawData);
    } finally {
        if (input != null) {
            input.close();
        }
    }

    DataOutputStream output = null;
    try {
        output = new DataOutputStream(new FileOutputStream(waveFile));
        // WAVE header
        // see http://ccrma.stanford.edu/courses/422/projects/WaveFormat/
        output.writeChars("RIFF"); // chunk id
        output.writeInt(36 + rawData.length); // chunk size
        output.writeChars("WAVE"); // format
        output.writeChars("fmt "); // subchunk 1 id
        output.writeInt(16); // subchunk 1 size
        output.writeShort((short) 1); // audio format (1 = PCM)
        output.writeShort((short) 1); // number of channels
        output.writeInt(SAMPLE_RATE); // sample rate
        output.writeInt(SAMPLE_RATE * 2); // byte rate
        output.writeShort((short) 2); // block align
        output.writeShort((short) 16); // bits per sample
        output.writeChars(output, "data"); // subchunk 2 id
        output.writeInt(output, rawData.length); // subchunk 2 size
        // Audio data (conversion big endian -> little endian)
        short[] shorts = new short[rawData.length / 2];
        ByteBuffer.wrap(rawData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts);
        ByteBuffer bytes = ByteBuffer.allocate(shorts.length * 2);
        for (short s : shorts) {
            bytes.putShort(s);
        }
        output.write(bytes.array());
    } finally {
        if (output != null) {
            output.close();
        }
    }
}