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写我的程序，但效果不是很好，我不知道我错在哪里。在此之前，我使用 byte [] 来存储来自 wav 的数据（它工作得很好但很吵）所以我切换到了 short []，但结果非常糟糕。

这是我的代码：

public class Mix extends Activity {


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    try {
        mixSound();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

private void mixSound() throws IOException {

    in1 = getResources().openRawResource(R.raw.media_b); //16-bit little-endian, 1411kbps, 44100Hz, 2 channels 
    in2 = getResources().openRawResource(R.raw.media_c); //16-bit little-endian, 1411kbps, 44100Hz, 2 channels 

    List<Short> music1  =  createMusicArray(in1);
    List<Short> music2  =  createMusicArray(in2);

    completeStreams(music1, music2);

    short[] arrayMusic1 = buildShortArray(music1);;
    short[] arrayMusic2 = buildShortArray(music2);

    output = new short[arrayMusic1.length];

    for (int i = 0; i < output.length; i++) {


    }

    saveToFile();
}




/**
 * createMusicArray reads the stream and returns a list of short objects (the samples)
 */
public List<Short> createMusicArray (InputStream ins) throws IOException {
    List<Short> musicList = new ArrayList<Short>();

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] byteArray           = new byte[50*1024];
    int i = Integer.MAX_VALUE;
    while ((i = ins.read(byteArray, 0, byteArray.length)) > 0) {
        baos.write(byteArray, 0, i);
    }

    for (int j = 0; j < byteArray.length; j++) {
        short objShort = (short)(byteArray[j]); 
        musicList.add(objShort);
    }

    return musicList;

}

/**
 * completeStreams normalizes the streams by adding  a series of '0' shorts at the end of smaller files. At the end the 2 files have all the same length.
 */
public void completeStreams(List<Short> mListShort_1, List<Short> mListShort_2) {
    //TODO: check length
    int size_a = mListShort_1.size();
    int size_b = mListShort_2.size();

    if (size_a > size_b){
        // adding series of '0'
        for (int i = size_b+1; i <= size_a; i++) {
            mListShort_2.set(i, (short) 0);
        }
    } else if (size_a < size_b) {
        for (int i = size_a+1; i <= size_b; i++) {
            mListShort_1.set(i, (short) 0);
        }
    } else {
        //do nothing
    }
}




private byte[] shortArrayToByteArray(short[] shortArr) {
    /**
    int index;
    int iterations = shortArr.length;
    ByteBuffer byteBuffer = ByteBuffer.allocate(shortArr.length * 2);

    for(index = 0; index != iterations; ++index){
      byteBuffer.putShort(shortArr[index]);    
    }

    return byteBuffer.array();
    */

    int short_index, byte_index;
    int iterations = shortArr.length;

    byte [] buffer = new byte[shortArr.length * 2];

    short_index = byte_index = 0;

    for(/*NOP*/; short_index != iterations; /*NOP*/) {
        buffer[byte_index]      =   (byte) (shortArr[short_index] & 0x00FF); 
        buffer[byte_index + 1]  =   (byte) ((shortArr[short_index] & 0xFF00) >> 8);

        ++short_index; byte_index += 2;
    }

    return buffer;
}

private byte[] intToByteArray(int i) {
    byte[] b = new byte[4];
    b[0]     = (byte) (i & 0x00FF);
    b[1]     = (byte) ((i >> 8)  & 0x000000FF);
    b[2]     = (byte) ((i >> 16) & 0x000000FF);
    b[3]     = (byte) ((i >> 24) & 0x000000FF);
    return b;
}

private byte[] shortToByteArray(short data) {
    byte[] b = new byte[2];
    b[0] = (byte) (data & 0xff);
    b[1] = (byte) ((data >> 8) & 0xff);
    return b;
}

public static long byteArrayToLong(byte[] b) {
    int  start = 0;
    int      i = 0;
    int    len = 4;
    int    cnt = 0;
    byte[] tmp = new byte[len];
    for (i = start; i < (start + len); i++) {
        tmp[cnt] = b[i];
        cnt++;
    }
    long accum = 0;
    i = 0;
    for (int shiftBy = 0; shiftBy < 32; shiftBy += 8) {
        accum |= ((long) (tmp[i] & 0xff)) << shiftBy;
        i++;
    }
    return accum;
}

}

你能帮助我吗。非常感谢你！

4

1 回答 1

1

您的主要问题在于此功能：

/**
 * createMusicArray reads the stream and returns a list of short objects (the samples)
 */
public List<Short> createMusicArray (InputStream ins) throws IOException {
    List<Short> musicList = new ArrayList<Short>();

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] byteArray           = new byte[50*1024];
    int i = Integer.MAX_VALUE;
    while ((i = ins.read(byteArray, 0, byteArray.length)) > 0) {
        baos.write(byteArray, 0, i);
    }

    for (int j = 0; j < byteArray.length; j++) {
        short objShort = (short)(byteArray[j]); 
        musicList.add(objShort);
    }

    return musicList;
}

似乎您正在获取原始字节并简单地将它们转换为短裤，但每个短裤都需要文件中两个字节的数据。（查看您如何在 shortArrayToByteArray 函数中正确处理此问题）。从文件中读取原始短裤的最简单方法是使用 DataInputStream。不幸的是，您还需要担心字节顺序，因此您需要从guava获取 LittleEndianDataInputStream ，或者如果您不想导入整个 guava 库，您可以编写自己的类来做同样的事情，就像这样。试试这个（未经测试，所以你可能需要调整它）：

/**
 * createMusicArray reads the stream and returns a list of short objects (the samples)
 */
public List<Short> createMusicArray (InputStream ins) throws IOException {
    LittleEndianDataInputStream dis = new LittleEndianDataInputStream(ins);

    while (true) {
        try {
            short d = dis.readShort();
            musicList.add(d);
        } catch( EOFException e ) {
            break;
        }
    }

    return musicList;
}

作为旁注，将所有数据存储在列表中然后将其传输到数组是非常低效的（并且令人困惑）。您应该考虑只使用 ArrayList，或者更好的是获取媒体数据的大小并首先使用它来构建正确大小的数组。但是，这些都不能确保您仍然可以执行操作，因为您正在尝试将整个文件放入内存中。相反，尝试读取每个文件的较小块，并将它们混合，然后读取下一个块。

但在你完成这项工作之前，我不会担心所有这些。

于 2013-05-31T14:59:16.750 回答