capturing internal audio java

问题

i will record the sound from my programs. I use Ubuntu 14.04 and PulseAudio. Now i try to record from pulseaudio but currently i'm only recording from my microphone. How can i record the sound from pulseaudio instead of my microphone?

public static void captureAudio() {
    try {
        final AudioFormat format = getFormat();
        DataLine.Info info = new DataLine.Info(TargetDataLine.class, format);
        final TargetDataLine line = (TargetDataLine) AudioSystem.getLine(info);
        line.open(format);
        line.start();
        Runnable runnable = new Runnable() {
            int bufferSize = (int)format.getSampleRate() * format.getFrameSize();
            byte buffer[] = new byte[bufferSize];

            public void run() {
                out = new ByteArrayOutputStream();
                running = true;
                try {
                    while (running) {
                        int count = line.read(buffer, 0, buffer.length);
                        if (count > 0) {
                            out.write(buffer, 0, count);
                        }
                    }
                    out.close();
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        };
        Thread captureThread = new Thread(runnable);
        captureThread.start();
    } catch (LineUnavailableException ex) {
        ex.printStackTrace();
    }
}

I tried some things to change this in my code:

Mixer mixer = AudioSystem.getMixer(null);

And then:

final TargetDataLine line = (TargetDataLine) mixer.getLine(info);

Hope anyone have a solution.

Greetings Daniel

回答1:

This problem cannot be solved from within Java alone. Java sees only the devices which are already there, as the following Java program demonstrates:

import javax.sound.sampled.*;

public class ListDevices {
    public static void main(final String... args) throws Exception {
        for (final Mixer.Info info : AudioSystem.getMixerInfo())
            System.out.format("%s: %s %s %s %s%n", info, info.getName(), info.getVendor(), info.getVersion(), info.getDescription());
    }
}

What you need to do is create a loopback device for your audio system. The following post shows how to do that: https://askubuntu.com/questions/257992/how-can-i-use-pulseaudio-virtual-audio-streams-to-play-music-over-skype The purpose was different, but it should be adaptable for your situation, as your situation seems simpler to me than the situation described in that post.

It should be possible to run those pactl commands from Java using Process.

来源：https://stackoverflow.com/questions/27473522/capturing-internal-audio-java

标签

java

audio

capture