java 读取wave

1. wave文件使用三个参数来表示声音：采样位数、采样频率和声道数。
2. 声道有单声道和立体声之分，,
3. 采样频率一般有： 11025Hz（11kHz）、22050Hz（22kHz）和44100Hz（44kHz）三种。
4. WAVE文件所占容量=（采样频率×采样位数×声道）×时间/8（1字节=8bit）

public static int toInt(byte[] b) {
    return ((b[3] << 24) + (b[2] << 16) + (b[1] << 8) + (b[0] << 0));
}

public static short toShort(byte[] b) {
    return (short)((b[1] << 8) + (b[0] << 0));
}

public static byte[] read(RandomAccessFile rdf, int pos, int length) throws IOException {
    rdf.seek(pos);
    byte result[] = new byte[length];
    for (int i = 0; i < length; i++) {
        result[i] = rdf.readByte();
    }
    return result;
}

public static void main(String[] args) throws IOException {

    File f = new File("c:\\bong.wav");
    RandomAccessFile rdf = null;
    rdf = new RandomAccessFile(f,"r");

    System.out.println("audio size: " + toInt(read(rdf, 4, 4))); // 声音尺寸

    System.out.println("audio format: " + toShort(read(rdf, 20, 2))); // 音频格式 1 = PCM

    System.out.println("num channels: " + toShort(read(rdf, 22, 2))); // 1 单声道 2 双声道

    System.out.println("sample rate: " + toInt(read(rdf, 24, 4)));  // 采样率、音频采样级别 8000 = 8KHz

    System.out.println("byte rate: " + toInt(read(rdf, 28, 4)));  // 每秒波形的数据量

    System.out.println("block align: " + toShort(read(rdf, 32, 2)));  // 采样帧的大小

    System.out.println("bits per sample: " + toShort(read(rdf, 34, 2)));  // 采样位数

    rdf.close();

}