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Diffstat (limited to 'servers/audio/effects/eq.cpp')
| -rw-r--r-- | servers/audio/effects/eq.cpp | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/servers/audio/effects/eq.cpp b/servers/audio/effects/eq.cpp new file mode 100644 index 0000000000..a6499a66b4 --- /dev/null +++ b/servers/audio/effects/eq.cpp @@ -0,0 +1,219 @@ +// +// C++ Interface: eq +// +// Description: +// +// +// Author: reduzio@gmail.com (C) 2006 +// +// Copyright: See COPYING file that comes with this distribution +// +// +#include "eq.h" +#include <math.h> +#include "error_macros.h" +#include "math_funcs.h" + +#define POW2(v) ((v)*(v)) + +/* Helper */ + static int solve_quadratic(double a,double b,double c,double *r1, double *r2) { +//solves quadractic and returns number of roots + + double base=2*a; + if (base == 0.0f) + return 0; + + double squared=b*b-4*a*c; + if (squared<0.0) + return 0; + + squared=sqrt(squared); + + *r1=(-b+squared)/base; + *r2=(-b-squared)/base; + + if (*r1==*r2) + return 1; + else + return 2; + } + +EQ::BandProcess::BandProcess() { + + c1=c2=c3=history.a1=history.a2=history.a3=0; + history.b1=history.b2=history.b3=0; +} + +void EQ::recalculate_band_coefficients() { + +#define BAND_LOG( m_f ) ( log((m_f)) / log(2) ) + + for (int i=0;i<band.size();i++) { + + double octave_size; + + double frq=band[i].freq; + + if (i==0) { + + octave_size=BAND_LOG(band[1].freq)-BAND_LOG(frq); + } else if (i==(band.size()-1)) { + + octave_size=BAND_LOG(frq)-BAND_LOG(band[i-1].freq); + } else { + + double next=BAND_LOG(band[i+1].freq)-BAND_LOG(frq); + double prev=BAND_LOG(frq)-BAND_LOG(band[i-1].freq); + octave_size=(next+prev)/2.0; + } + + + + double frq_l=round(frq/pow(2.0,octave_size/2.0)); + + + + double side_gain2=POW2(Math_SQRT12); + double th=2.0*Math_PI*frq/mix_rate; + double th_l=2.0*Math_PI*frq_l/mix_rate; + + double c2a=side_gain2 * POW2(cos(th)) + - 2.0 * side_gain2 * cos(th_l) * cos(th) + + side_gain2 + - POW2(sin(th_l)); + + double c2b=2.0 * side_gain2 * POW2(cos(th_l)) + + side_gain2 * POW2(cos(th)) + - 2.0 * side_gain2 * cos(th_l) * cos(th) + - side_gain2 + + POW2(sin(th_l)); + + double c2c=0.25 * side_gain2 * POW2(cos(th)) + - 0.5 * side_gain2 * cos(th_l) * cos(th) + + 0.25 * side_gain2 + - 0.25 * POW2(sin(th_l)); + + //printf("band %i, precoefs = %f,%f,%f\n",i,c2a,c2b,c2c); + + double r1,r2; //roots + int roots=solve_quadratic(c2a,c2b,c2c,&r1,&r2); + + ERR_CONTINUE( roots==0 ); + + band[i].c1=2.0 * ((0.5-r1)/2.0); + band[i].c2=2.0 * r1; + band[i].c3=2.0 * (0.5+r1) * cos(th); + //printf("band %i, coefs = %f,%f,%f\n",i,(float)bands[i].c1,(float)bands[i].c2,(float)bands[i].c3); + + } +} + +void EQ::set_preset_band_mode(Preset p_preset) { + + + band.clear(); + +#define PUSH_BANDS(m_bands) \ + for (int i=0;i<m_bands;i++) { \ + Band b; \ + b.freq=bands[i];\ + band.push_back(b);\ + } + + switch (p_preset) { + + case PRESET_6_BANDS: { + + static const double bands[] = { 32 , 100 , 320 , 1e3, 3200, 10e3 }; + PUSH_BANDS(6); + + } break; + + case PRESET_8_BANDS: { + + static const double bands[] = { 32,72,192,512,1200,3000,7500,16e3 }; + + PUSH_BANDS(8); + } break; + + case PRESET_10_BANDS: { + static const double bands[] = { 31.25, 62.5, 125 , 250 , 500 , 1e3, 2e3, 4e3, 8e3, 16e3 }; + + PUSH_BANDS(10); + + } break; + + case PRESET_21_BANDS: { + + static const double bands[] = { 22 , 32 , 44 , 63 , 90 , 125 , 175 , 250 , 350 , 500 , 700 , 1e3, 1400 , 2e3, 2800 , 4e3, 5600 , 8e3, 11e3, 16e3, 22e3 }; + PUSH_BANDS(21); + + } break; + + case PRESET_31_BANDS: { + + static const double bands[] = { 20, 25, 31.5, 40 , 50 , 63 , 80 , 100 , 125 , 160 , 200 , 250 , 315 , 400 , 500 , 630 , 800 , 1e3 , 1250 , 1600 , 2e3, 2500 , 3150 , 4e3, 5e3, 6300 , 8e3, 10e3, 12500 , 16e3, 20e3 }; + PUSH_BANDS(31); + } break; + + }; + + recalculate_band_coefficients(); +} + +int EQ::get_band_count() const { + + return band.size(); +} +float EQ::get_band_frequency(int p_band) { + + ERR_FAIL_INDEX_V(p_band,band.size(),0); + return band[p_band].freq; +} +void EQ::set_bands(const Vector<float>& p_bands) { + + band.resize(p_bands.size()); + for (int i=0;i<p_bands.size();i++) { + + band[i].freq=p_bands[i]; + } + + recalculate_band_coefficients(); + +} + +void EQ::set_mix_rate(float p_mix_rate) { + + mix_rate=p_mix_rate; + recalculate_band_coefficients(); +} + +EQ::BandProcess EQ::get_band_processor(int p_band) const { + + + EQ::BandProcess band_proc; + + ERR_FAIL_INDEX_V(p_band,band.size(),band_proc); + + band_proc.c1=band[p_band].c1; + band_proc.c2=band[p_band].c2; + band_proc.c3=band[p_band].c3; + + return band_proc; + + +} + + +EQ::EQ() +{ + mix_rate=44100; +} + + +EQ::~EQ() +{ +} + + |