如何用Java sound缓冲和播放OGG文件中的声音数据

Question

我试图使用Java声音（与MP3SPI和VorbisSPI一起）从WAV、MP3和OGG文件中读取音频数据，并将其存储到字节数组中，以便以后从那里播放。为了做到这一点，我使用如下代码：

public Sound loadSound(File file){ 
   AudioInputStream baseStream = AudioSystem.getAudioInputStream(file);
   AudioFormat baseFormat = baseStream.getFormat();
   AudioFormat decodedFormat = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
                    baseFormat.getSampleRate(),
                    16,
                    baseFormat.getChannels(),
                    baseFormat.getChannels() * 2,
                    baseFormat.getSampleRate(),
                    false);
    AudioInputStream decodedStream = AudioSystem.getAudioInputStream(decodedFormat, baseStream);
    // Buffer audio data from audio stream
    ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
    byte[] buffer = new byte[4096];
                int nBytesRead = 0;
                while (nBytesRead != -1) {
                    nBytesRead = decodedStream.read(buffer, 0, buffer.length);
                    // Write read bytes to out stream
                    byteOut.write(buffer);
                }
    // close streams and cleanup
    byte[] samples = byteOut.toByteArray();

    return new Sound(samples,decodedFormat);
}

Sound类基本上是一个(Byte[]样本，AudioFormat格式）耦合。完成后，我尝试读取和播放字节数组，如下所示：

public void play(Sound sound) {
    InputStream source = new ByteArrayInputStream(sound.getSamples());
    AudioFormat format = sound.getFormat();
    // use a short, 100ms (1/10th sec) buffer for real-time changes to the sound stream
    int bufferSize = format.getFrameSize()
            * Math.round(format.getSampleRate() / 10);
    byte[] buffer = new byte[bufferSize];

    // create a line to play to
    SourceDataLine line;
    try {
        DataLine.Info info
                = new DataLine.Info(SourceDataLine.class, format);
        line = (SourceDataLine) AudioSystem.getLine(info);
        line.open(format, bufferSize);
    } catch (LineUnavailableException ex) {
        ex.printStackTrace();
        return;
    }

    // start the line
    line.start();

    // copy data to the line
    try {
        int numBytesRead = 0;
        while (numBytesRead != -1) {
            numBytesRead
                    = source.read(buffer, 0, buffer.length);
            if (numBytesRead != -1) {
                line.write(buffer, 0, numBytesRead);
            }
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    } catch (ArrayIndexOutOfBoundsException ex2) {

    }

    // wait until all data is played, then close the line
    line.drain();
    line.close();

}

Answer 1

问题出在loadsound中，在下面的write调用中没有使用nbytesread返回值。返回请求的完整字节数不需要read函数。事实上，如果解码器可以打破它的自然边界，它可能会使解码器更容易实现。这可能就是ogg解码器正在做的事情。此外，如果不使用返回值，那么very read调用不太可能返回所请求的准确大小。

            byte[] buffer = new byte[4096];
            int nBytesRead = 0;
            while (nBytesRead != -1) {
                nBytesRead = decodedStream.read(buffer, 0, buffer.length);
                // Write read bytes to out stream
                byteOut.write(buffer, 0, nBytesRead);
                //                    ^^^^^^^^^^^^^
            }