src/add-ons/media/media-add-ons/equalizer/Equalizer.cpp

   1 /*
   2  * Copyright 2012, Gerasim Troeglazov (3dEyes**), 3dEyes@gmail.com.
   3  * All rights reserved.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7 #include <stdlib.h>
   8 #include <math.h>
   9 #include <string.h>
  10
  11 #include "Equalizer.h"
  12
  13 Equalizer::Equalizer()
  14 {
  15         fActivated = false;
  16         CleanUp();
  17 }
  18
  19 Equalizer::~Equalizer()
  20 {
  21 }
  22
  23 void
  24 Equalizer::SetFormat(int channels, float framerate)
  25 {
  26     fChannels = channels;
  27     fRate = framerate;
  28
  29     memset(fWDataVector[0][0], 0, sizeof(fWDataVector));
  30
  31     fActiveBands = BandCount();
  32     while(fFrequency[fActiveBands-1] * 2.0 > fRate) {
  33         fActiveBands--;
  34     }
  35
  36     for(int i = 0; i < fActiveBands; i++) {
  37         BandPassFilterCalcs(fAWeights[i], fBWeights[i],
  38                                                 fFrequency[i] / (float)fRate);
  39     }
  40 }
  41
  42 void
  43 Equalizer::SetPreAmp(double value)
  44 {
  45         fPreAmp = value;
  46         RecalcGains();
  47 }
  48
  49 double
  50 Equalizer::PreAmp(void)
  51 {
  52         return fPreAmp;
  53 }
  54
  55 void
  56 Equalizer::SetBand(int band, double value)
  57 {
  58         if (band < 0 || band >= BandCount())
  59                 return;
  60
  61         fBands[band] = value;
  62         RecalcGains();
  63 }
  64
  65 double
  66 Equalizer::Band(int band)
  67 {
  68         if (band < 0 || band >= BandCount())
  69                 return 0.0;
  70
  71         return fBands[band];
  72 }
  73
  74 int
  75 Equalizer::BandCount(void)
  76 {
  77         return EQ_BANDS;
  78 }
  79
  80 float
  81 Equalizer::BandFrequency(int band)
  82 {
  83         if (band < 0 || band >= BandCount())
  84                 return 0.0;
  85
  86         return fFrequency[band];
  87 }
  88
  89 void
  90 Equalizer::ProcessBuffer(float* buffer, int samples)
  91 {
  92    if (!fActivated || samples <= 0)
  93         return;
  94
  95    for(int i = 0; i < fChannels; i++) {
  96                 float *g = fGainVector[i];
  97         float *end = buffer + samples;
  98         for(float *fptr = buffer + i; fptr < end; fptr += fChannels) {
  99             float yt = *fptr;
 100             for (int k = 0; k < fActiveBands; k ++) {
 101                 float *Wq = fWDataVector[i][k];
 102                 float w = yt * fBWeights[k][0] +
 103                                 Wq[0] * fAWeights[k][0] +
 104                                 Wq[1] * fAWeights[k][1];
 105                 yt += (w + Wq[1] * fBWeights[k][1]) * g[k];
 106                 Wq[1] = Wq[0];
 107                 Wq[0] = w;
 108             }
 109             *fptr = yt;
 110         }
 111     }
 112 }
 113
 114 void
 115 Equalizer::CleanUp()
 116 {
 117         float freq[EQ_BANDS] = {31.25, 62.5, 125, 250, 500, 1000, 2000, 4000, 8000, 16000};
 118
 119         for(int i = 0; i < BandCount(); i++) {
 120                 fFrequency[i] = freq[i];
 121                 fBands[i] = 0.0;
 122         }
 123
 124         fPreAmp = 0.0;
 125         RecalcGains();
 126 }
 127
 128 void
 129 Equalizer::RecalcGains(void)
 130 {
 131     float adjust[EQ_BANDS];
 132
 133     for(int i = 0; i < BandCount(); i++)
 134         adjust[i] = fPreAmp + fBands[i];
 135
 136     for(int c = 0; c < MAX_CHANNELS; c++)
 137         for(int i = 0; i<BandCount(); i++)
 138            fGainVector[c][i] = pow(10, adjust[i] / 20) - 1;
 139
 140     fActivated = true;
 141 }
 142
 143 void
 144 Equalizer::BandPassFilterCalcs(float *a, float *b, float f)
 145 {
 146         float q = 1.2247449;
 147     float theta = 2.0 * M_PI * f;
 148     float c_value = (1 - tanf(theta * q / 2.0)) / (1 + tanf(theta * q / 2.0));
 149
 150     a[0] = (1 + c_value) * cosf(theta);
 151     a[1] = -c_value;
 152     b[0] = (1 - c_value) / 2.0;
 153     b[1] = -1.005;
 154 }