Audio.pde

   1 /**
   2  * This is a reusable equalizer class that lets you get averaged
   3  * bands with dB scaling and smoothing.
   4  */
   5 public static class GraphicEQ {
   6
   7   private final LX lx;
   8
   9   public final BasicParameter level = new BasicParameter("LVL", 0.5);
  10   public final BasicParameter range = new BasicParameter("RNGE", 0.5);
  11   public final BasicParameter slope = new BasicParameter("SLOP", 0.5);
  12   public final BasicParameter attack = new BasicParameter("ATK", 0.5);
  13   public final BasicParameter release = new BasicParameter("REL", 0.5);
  14
  15   private final FFT fft;
  16   private final int numBands;
  17
  18   private final LinearEnvelope[] bandVals;
  19
  20   public final static int DEFAULT_NUM_BANDS = 16;
  21
  22   public GraphicEQ(LX lx) {
  23     this(lx, DEFAULT_NUM_BANDS);
  24   }
  25
  26   /**
  27    * Note that the number of bands is a suggestion. Due to the FFT implementation
  28    * the actual number may be slightly different.
  29    */
  30   public GraphicEQ(LX lx, int num) {
  31     this.lx = lx;
  32     fft = new FFT(lx.audioInput().bufferSize(), lx.audioInput().sampleRate());
  33     fft.window(FFT.HAMMING);
  34     fft.logAverages(50, num/8);
  35     numBands = this.fft.avgSize();
  36     bandVals = new LinearEnvelope[numBands];
  37     for (int i = 0; i < bandVals.length; ++i) {
  38       (bandVals[i] = new LinearEnvelope(0, 0, 500)).trigger();
  39     }
  40   }
  41
  42   static final float logTen = log(10);
  43   public static float log10(float val) {
  44     return log(val) / logTen;
  45   }
  46
  47   public float getLevel(int band) {
  48     return bandVals[band].getValuef();
  49   }
  50
  51   public float getAverageLevel(int minBand, int numBands) {
  52     float avg = 0;
  53     for (int i = minBand; i < minBand + numBands; ++i) {
  54       avg += bandVals[i].getValuef();
  55     }
  56     avg /= numBands;
  57     return avg;
  58   }
  59
  60   public void run(double deltaMs) {
  61     fft.forward(lx.audioInput().mix);
  62     float zeroDBReference = pow(10, 100*(1-level.getValuef())/20.);
  63     float decibelRange = 12 + range.getValuef() * 60;
  64     float decibelSlope = slope.getValuef() * 60.f / numBands;
  65     for (int i = 0; i < numBands; ++i) {
  66       float raw = fft.getAvg(i);
  67       float decibels = 20*log10(raw / zeroDBReference);
  68       float positiveDecibels = decibels + decibelRange;
  69       positiveDecibels += i*decibelSlope;
  70       float value = constrain(positiveDecibels / decibelRange, 0, 1);
  71
  72       if (value > bandVals[i].getValuef()) {
  73         bandVals[i].setRangeFromHereTo(value, attack.getValuef() * 20).trigger();
  74       }
  75     }
  76     for (LinearEnvelope band : bandVals) {
  77       band.run(deltaMs);
  78       if (!band.isRunning() && band.getValuef() > 0) {
  79         band.setRangeFromHereTo(0, release.getValuef() * 1600).trigger();
  80       }
  81     }
  82   }
  83 }
  84
  85