java - JAVA音频数据流0s

Question

我一直在写一个简短的程序，将音频从线路输入/麦克风重定向到扬声器。我只是在学习大部分，但是我的工作似乎已经成为我想要的工作模型。但是，当我打印TargetDataLine缓冲区时，它会打印所有0，就好像它已连接并正在流式传输一样，但是听不到我的输入。至此，我已经研究了大多数sampled软件包的内容以及论坛，教程和其他人的代码中在线提供的内容，由于令人失望的缺乏已发布的音频代码，我认为我的学习资源几乎耗尽了。因此，如果任何人有任何建议或资源，将不胜感激。我认为您不需要其他任何代码，但是如果需要，请问一下。此代码使用Eclipse version: 4.3.0.v20130605在我的计算机上编译时没有错误或警告。

这是该类的方法索引，可为您节省200条代码中的大部分。

class Stream extends Thread {
    vars
    ...
    Stream()
    setProcessingBuffer()
    setRenderingBuffer()
    bytesToString()
    play()
    pause()
    run() (Override)
}

码:

package moshi;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Line;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.Mixer;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.TargetDataLine;

/**
 * @author KN
 * @version 1.0 Build 1 October 26, 2013
 * 
 *          This concurrent process sets up and controls the streaming of audio
 *          data via input and output buffers.
 * 
 * @see {@link Thread}, {@link AudioSystem}, {@link TargetDataLine},
 *      {@link SourceDataLine}
 */

public class Stream extends Thread {

    /** The {@link AudioFormat} used in encoding/decoding streaming audio data */
    public final static AudioFormat audioFormat = new AudioFormat(48000, 16, 2, true, true);

    /**
     * {@link String} describing the name of the audio device to be used.
     * <p>
     * Example: "Line In", "Microphone"
     */
    private static String INPUT = "Mic";
    /**
     * {@link String} describing the name of the audio device to be used.
     * <p>
     * Example: "Speakers", "Line Out"
     */
    private static String OUTPUT = "Speakers";

    /**
     * {@link #PROCESSING_BUFFER} is a buffer used for receiving audio data
     * 
     * @see TargetDataLine
     */
    private static TargetDataLine PROCESSING_BUFFER;
    /**
     * {@link #RENDERING_BUFFER} is a buffer used for writing audio data
     * 
     * @see SourceDataLine
     */
    private static SourceDataLine RENDERING_BUFFER;
    /** {@link Integer} specifying the buffer sizes in bytes */
    private static int BUFFER_SIZE = 2048;
    /** {@link Byte[]} for holding raw audio data */
    private static byte[] READ_BUFFER = new byte[Stream.BUFFER_SIZE];

    /**
     * Initiates the audio hardware read/write buffers into
     * {@link TargetDataLine}s and {@link SourceDataLine}s respectively.
     * 
     * @see {@link TargetDataLine}, {@link SourceDataLine}
     */
    public Stream() {
        setProcessingBuffer();
        setRenderingBuffer();
    }

    /**
     * Queries input Lines and stores the {@link TargetDataLine} at
     * {@link #PROCESSING_BUFFER}
     * 
     * @see {@link AudioSystem}, {@link Line}, {@link TargetDataLine},
     *      {@link Mixer}
     */
    private void setProcessingBuffer() {
        final Mixer.Info[] mixerInfos = AudioSystem.getMixerInfo();
        for (final Mixer.Info info : mixerInfos) {
            final Mixer mixer = AudioSystem.getMixer(info);
            final Line.Info[] targetLineInfos = mixer.getTargetLineInfo();
            for (final Line.Info targetLineInfo : targetLineInfos) {
                if (targetLineInfo.getLineClass() == javax.sound.sampled.TargetDataLine.class
                    && info.getName().startsWith(Stream.INPUT)) {
                    try {
                        Stream.PROCESSING_BUFFER = (TargetDataLine) mixer.getLine(targetLineInfo);
                        System.out.println(targetLineInfo.getLineClass() + ": " + info.getName() + " ["
                            + Stream.PROCESSING_BUFFER + "] ");
                    } catch (LineUnavailableException e) {
                        e.printStackTrace();
                    }
                } else {
                }
            }
        }
    }

    /**
     * Queries output Lines and stores the {@link SourceDataLine} at
     * {@link #RENDERING_BUFFER}
     * 
     * @see {@link AudioSystem}, {@link Line}, {@link SourceDataLine},
     *      {@link Mixer}
     */
    private void setRenderingBuffer() {
        final Mixer.Info[] mixerInfos = AudioSystem.getMixerInfo();
        for (Mixer.Info info : mixerInfos) {
            final Mixer mixer = AudioSystem.getMixer(info);
            final Line.Info[] sourceLineInfos = mixer.getSourceLineInfo();
            for (final Line.Info sourceLineInfo : sourceLineInfos) {
                if (sourceLineInfo.getLineClass() == javax.sound.sampled.SourceDataLine.class
                    && info.getName().startsWith(Stream.OUTPUT)) {
                    try {
                        Stream.RENDERING_BUFFER = (SourceDataLine) mixer.getLine(sourceLineInfo);
                        System.out.println(sourceLineInfo.getLineClass() + ": " + info.getName() + " ["
                            + Stream.RENDERING_BUFFER + "]");
                    } catch (LineUnavailableException e) {
                        e.printStackTrace();
                    }
                } else {
                }
            }
        }
    }

    /**
     * Takes in an array of bytes and returns a String object representation of
     * the data
     * 
     * @param array
     *            The byte array to be converted
     * @return The string object representation of a byte array
     */
    private static String bytesToString(byte[] array) {
        String toString = "";
        for (byte currentByte : array) {
            toString += currentByte;
        }
        return toString;
    }

    /**
     * Opens buffers {@link #PROCESSING_BUFFER} and {@link #RENDERING_BUFFER}
     * for reading/writing
     */
    public static void play() {
        try {
            if (!Stream.PROCESSING_BUFFER.isOpen()) {
                Stream.PROCESSING_BUFFER.open(Stream.audioFormat, Stream.BUFFER_SIZE);
            }
            if (!Stream.RENDERING_BUFFER.isOpen()) {
                Stream.RENDERING_BUFFER.open(Stream.audioFormat, Stream.BUFFER_SIZE);
                Stream.RENDERING_BUFFER.start();
            }

            while (Stream.RENDERING_BUFFER.isOpen()) {
                Stream.PROCESSING_BUFFER.read(Stream.READ_BUFFER, 0, Stream.BUFFER_SIZE);
                System.out.println(Stream.bytesToString(Stream.READ_BUFFER));
                Stream.RENDERING_BUFFER.write(Stream.READ_BUFFER, 0, Stream.BUFFER_SIZE);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Stops buffers {@link #PROCESSING_BUFFER} and {@link #RENDERING_BUFFER}
     * from reading/writing
     */
    public static void pause() {
        if (Stream.PROCESSING_BUFFER.isOpen()) {
            Stream.PROCESSING_BUFFER.close();
        }
        if (Stream.RENDERING_BUFFER.isOpen()) {
            Stream.RENDERING_BUFFER.stop();
            Stream.RENDERING_BUFFER.close();
        }
    }

    /** {@inheritDoc} */
    @Override
    public void run() {
    }
}

输出:

interface javax.sound.sampled.TargetDataLine: Microphone (Realtek High Defini [com.sun.media.sound.DirectAudioDevice$DirectTDL@2f57d162] 
interface javax.sound.sampled.SourceDataLine: Speakers (Realtek High Definition Audio) [com.sun.media.sound.DirectAudioDevice$DirectSDL@79b7d13e]
0000000000000000000000000000000000000000000000000000000000000...... And a lot more of that

Answer 1

让我们看一下:

Stream.PROCESSING_BUFFER.read(Stream.READ_BUFFER, 0, Stream.BUFFER_SIZE);

如果一切正常，它将读取数据，直到缓冲区已满，但是在您的情况下，一切都不好，实际上，它没有读取任何内容，您可以通过检查read返回的值来判断:

int numRead = Stream.PROCESSING_BUFFER.read(Stream.READ_BUFFER, 0, Stream.BUFFER_SIZE);

numRead为0，并且Stream.READ_BUFFER中未放入任何内容。

为了确保您输出已读取的数据，您需要使用:

Stream.RENDERING_BUFFER.write(Stream.READ_BUFFER, 0, numRead);

您什么都不读的原因是因为您尚未启动TargetDataLine，您需要:

if (!Stream.PROCESSING_BUFFER.isOpen()) {
    Stream.PROCESSING_BUFFER.open(Stream.audioFormat, Stream.BUFFER_SIZE);
    Stream.PROCESSING_BUFFER.start();
}