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I have a callback that gets incoming audio data as FloatBuffer containing 1024 floats that gets called several times per second. But I need an AudioInputStream since my system only works with them.

Converting the floats into 16bit PCM isgned audio data is not a problem, but I cannot create an InputStream out of it. The AudioInputStream constructor only accepts data with known length, but I have a constant stream. The AudioSystem.getAudioInputStream throws an "java.io.IOException: mark/reset not supported" if I feed it with a PipedInputStream containing the audio data.

Any ideas?

Here's my current code:

Jack jack = Jack.getInstance();
JackClient client = jack.openClient("Test", EnumSet.noneOf(JackOptions.class), EnumSet.noneOf(JackStatus.class));
JackPort in = client.registerPort("in", JackPortType.AUDIO, EnumSet.of(JackPortFlags.JackPortIsInput));

PipedInputStream pin = new PipedInputStream(1024 * 1024 * 1024);
PipedOutputStream pout = new PipedOutputStream(pin);
client.setProcessCallback(new JackProcessCallback() {
public boolean process(JackClient client, int nframes) {
    FloatBuffer inData = in.getFloatBuffer();
    byte[] buffer = new byte[inData.capacity() * 2];
    for (int i = 0; i < inData.capacity(); i++) {
        int sample = Math.round(inData.get(i) * 32767);
        buffer[i * 2] = (byte) sample;
        buffer[i * 2 + 1] = (byte) (sample >> 8);
    }
    try {
        pout.write(buffer, 0, buffer.length);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return true;
}
});
client.activate();
client.transportStart();

Thread.sleep(10000);
client.transportStop();
client.close();

AudioInputStream audio = AudioSystem.getAudioInputStream(new BufferedInputStream(pin, 1024 * 1024 * 1024));
AudioSystem.write(audio, Type.WAVE, new File("test.wav"));

It uses the JnaJack library, but it doesn't really matter where the data comes from. The conversion to bytes is fine by the way: writing that data directly to a SourceDataLine will work correctly. But I need the data as AudioInputStream.

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1 回答 1

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AudioSystem.getAudioInputStream 需要符合支持的AudioFileFormat的流，这意味着它必须符合已知类型。从文档中：

流必须指向有效的音频文件数据。

并且还来自该文档：

此方法的实现可能需要多个解析器检查流以确定它们是否支持它。这些解析器必须能够标记流，读取足够的数据以确定它们是否支持流，并将流的读取指针重置为其原始位置。如果输入流不支持这些操作，则此方法可能会失败并显示IOException.

您可以使用三参数构造函数创建自己的 AudioInputStream。如果长度未知，可以指定为AudioSystem.NOT_SPECIFIED。令人沮丧的是，构造函数文档和类文档都没有提到这一点，但其他构造函数的文档却提到了这一点。

于 2018-04-10T21:38:06.203 回答