LEDControl/src/main/java/de/zuim/ledcontrol/effects/AudioEffect.java

package de.zuim.ledcontrol.effects;

import com.tagtraum.jipes.math.FFTFactory;
import com.tagtraum.jipes.math.Transform;
import de.zuim.ledcontrol.LEDEffect;

import javax.sound.sampled.*;
import java.util.ArrayList;
import java.util.List;

public abstract class AudioEffect implements LEDEffect {

	private final List<AudioData> cachedAudioData = new ArrayList<>();
	private final static int BUFFERSIZE = 4096;
	private Thread audioThread = null;

	@Override
	public void load() {
		Runnable audioRunnable = () -> {

			Mixer.Info[] mixers = AudioSystem.getMixerInfo();
			List<Line.Info> availableTargetLines = new ArrayList<>();
			Mixer mixer = null;
			for (Mixer.Info mixerInfo : mixers) {

				Mixer m = AudioSystem.getMixer(mixerInfo);

				Line.Info[] lines = m.getTargetLineInfo();
				System.out.println(mixerInfo);

				for (Line.Info li : lines) {
					try {
						if (li instanceof DataLine.Info && mixerInfo.toString().contains("mix")) {
							m.open();
							mixer = m;
							System.out.println("(" + availableTargetLines.size() + ") Found target line: " + li + "  " + mixerInfo + "(" + li.getClass() + ")");
							availableTargetLines.add(li);
							m.close();
						}
					} catch (LineUnavailableException e) {
						System.out.println("Line unavailable.");
					}
				}
			}

			DataLine.Info targetLineInfo = (DataLine.Info) availableTargetLines.get(0);

			System.out.println("SUPPORTED TARGET FORMATS: ");
			AudioFormat[] formats = (targetLineInfo).getFormats();
			for (int i = 0; i < formats.length; i++) {
				System.out.println("(" + i + ")" + formats[i]);
			}
			AudioFormat format = formats[formats.length > 10 ? 64 : 2];


			System.out.println("SELECTED: " + format);


			final DataLine.Info info = new DataLine.Info(TargetDataLine.class, format);
			final AudioInputStream audioStream;

			//verbesserung: https://stackoverflow.com/a/51240462
			try {
				//TargetDataLine targetLine = (TargetDataLine) AudioSystem.getLine(info);
				TargetDataLine targetLine = (TargetDataLine) mixer.getLine(info);
				targetLine.open();
				targetLine.start();
				audioStream = new AudioInputStream(targetLine);

				final byte[] buf = new byte[BUFFERSIZE];

				final int numberOfSamples = buf.length / format.getFrameSize();
				final Transform fft = FFTFactory.getInstance().create(numberOfSamples);
				while (audioThread != null) {
					int read = audioStream.read(buf);

					float[] fBuf = decode(buf, format);

					final float[][] transformed = fft.transform(fBuf);
					final float[] realPart = transformed[0];
					final float[] imaginaryPart = transformed[1];
					double[] magnitudes = toMagnitudes(realPart, imaginaryPart);
					cachedAudioData.add(new AudioData(magnitudes, targetLine.getLevel()));

                    /*System.out.println("M"+ Arrays.toString(magnitudes));
                    float max = 0, avg = 0, min = 11111111;
                    for (float m : fBuf) {
                        avg += m;
                        if (m > max)
                            max = (int) m;
                        if (m < min)
                            min = (int) m;
                    }
                    System.out.println("M"+ max+"  "+min+"   "+avg/fBuf.length+ "  "+read+"  "+fBuf.length);*/

				}

				audioStream.close();
				targetLine.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		};

		audioThread = new Thread(audioRunnable);
		audioThread.start();
	}

	@Override
	public void unload() {
		if (audioThread != null && audioThread.isAlive())
			audioThread = null;
	}

	public List<AudioData> getData() {
		return cachedAudioData;
	}

	public int getMagnitudeLength() {
		return cachedAudioData.isEmpty() ? 0 : cachedAudioData.get(0).magnitudes.length;
	}

	private static float[] decode(final byte[] buf, final AudioFormat format) {
		final float[] fbuf = new float[buf.length / format.getFrameSize()];
		for (int pos = 0; pos < buf.length; pos += format.getFrameSize()) {
			final int sample = format.isBigEndian()
					? byteToIntBigEndian(buf, pos, format.getFrameSize())
					: byteToIntLittleEndian(buf, pos, format.getFrameSize());
			// normalize to [0,1]
			fbuf[pos / format.getFrameSize()] = sample / (Short.MAX_VALUE + 1.0f);
		}
		return fbuf;
	}

	private static double[] toMagnitudes(final float[] realPart, final float[] imaginaryPart) {
		final double[] powers = new double[realPart.length / 2];
		for (int i = 0; i < powers.length; i++) {
			powers[i] = Math.sqrt(realPart[i] * realPart[i] + imaginaryPart[i] * imaginaryPart[i]);
		}
		return powers;
	}

	private static int byteToIntLittleEndian(final byte[] buf, final int offset, final int bytesPerSample) {
		int sample = 0;
		for (int byteIndex = 0; byteIndex < bytesPerSample; byteIndex++) {
			final int aByte = buf[offset + byteIndex] & 0xff;
			sample += aByte << 8 * (byteIndex);
		}
		return sample;
	}

	private static int byteToIntBigEndian(final byte[] buf, final int offset, final int bytesPerSample) {
		int sample = 0;
		for (int byteIndex = 0; byteIndex < bytesPerSample; byteIndex++) {
			final int aByte = buf[offset + byteIndex] & 0xff;
			sample += aByte << (8 * (bytesPerSample - byteIndex - 1));
		}
		return sample;
	}

	static class AudioData {
		public double[] magnitudes;
		public float level;

		public AudioData(double[] magnitudes, float level) {
			this.magnitudes = magnitudes;
			this.level = level;
		}
	}
}