java 录音

Question

我有一个软件，可以记录 5 秒的声音间隔，然后将其发送进行处理。它以无限循环运行，如下所示：

while (true) {
    System.out.println("recording..");
    recorder.start();
    Thread.sleep(5000);
    recorder.stop();
    Thread.sleep(300);
    System.out.println("recording finished");

    data = toolkit.readInputStream(recorder.getInputStream());

    pkt = create(data);

    outport.send(pkt);
}

在上面的代码中，我必须在录制完成后添加一行 Thread.sleep(300); ，否则 recorder.getInputStream() 返回 null。为什么会发生这种情况？有没有办法改变它，这样就不需要延迟？

记录器代码：

    public class SoundRecorder implements Runnable{


        final int bufSize = 16384;

        AudioInputStream audioInputStream;
        String errStr;
        double duration, seconds;
        File file;

     public void start() {
                errStr = null;
                thread = new Thread(this);
                thread.setName("Capture");
                thread.start();
            }

            public void stop() {
                thread = null;
            }

 private void shutDown(String message) {
            if ((errStr = message) != null && thread != null) {
                thread = null;
                System.err.println(errStr);

            }
        }


      public void run() {

                duration = 0;
                audioInputStream = null;


                // define the required attributes for our line,
                // and make sure a compatible line is supported.

                AudioFormat format = getFormat();
                DataLine.Info info = new DataLine.Info(TargetDataLine.class,
                        format);

                if (!AudioSystem.isLineSupported(info)) {
                    shutDown("Line matching " + info + " not supported.");
                    return;
                }

                // get and open the target data line for capture.

                try {
                    line = (TargetDataLine) AudioSystem.getLine(info);
                    line.open(format, line.getBufferSize());
                } catch (LineUnavailableException ex) {
                    shutDown("Unable to open the line: " + ex);
                    return;
                } catch (SecurityException ex) {
                    shutDown(ex.toString());

                    return;
                } catch (Exception ex) {
                    shutDown(ex.toString());
                    return;
                }

                // play back the captured audio data
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                int frameSizeInBytes = format.getFrameSize();
                int bufferLengthInFrames = line.getBufferSize() / 8;
                int bufferLengthInBytes = bufferLengthInFrames * frameSizeInBytes;
                byte[] data = new byte[bufferLengthInBytes];
                int numBytesRead;

                line.start();

                while (thread != null) {
                    if ((numBytesRead = line.read(data, 0, bufferLengthInBytes)) == -1) {
                        break;
                    }
                    out.write(data, 0, numBytesRead);
                }

                // we reached the end of the stream.  stop and close the line.
                line.stop();
                line.close();
                line = null;

                // stop and close the output stream
                try {
                    out.flush();
                    out.close();
                } catch (IOException ex) {
                    ex.printStackTrace();
                }

                // load bytes into the audio input stream for playback

                byte audioBytes[] = out.toByteArray();
                ByteArrayInputStream bais = new ByteArrayInputStream(audioBytes);
                audioInputStream = new AudioInputStream(bais, format, audioBytes.length / frameSizeInBytes);

                long milliseconds = (long) ((audioInputStream.getFrameLength() * 1000) / format.getFrameRate());
                duration = milliseconds / 1000.0;



                try {
                    audioInputStream.reset();
                } catch (Exception ex) {
                    ex.printStackTrace();
                    return;
                }


            }

    public AudioInputStream getInputStream() {
            return audioInputStream;
        }

    public AudioFormat getFormat() {

            AudioFormat.Encoding encoding = AudioFormat.Encoding.PCM_SIGNED;
            float rate = 44100.0F;
            int sampleSize = 16;
            boolean bigEndian = true;
            int channels = 2;

            return new AudioFormat(encoding, rate, sampleSize,
                    channels, (sampleSize / 8) * channels, rate, bigEndian);

        }
    }

Answer 1

您告诉在后台运行的线程停止，并且编写的代码在退出时需要执行一些清理工作。因此，您必须等待线程完成才能使用某些功能。

您可以做的是将 stop 函数更改为如下所示：

public void stop() {
    Thread t = thread;
    thread = null;// this will cause your thread to exit
    t.join();//this will wait for the thread to exit before returning.
}