From 3538e6636edc1ba0b75e7409db618dbb7fe79d3e Mon Sep 17 00:00:00 2001 From: David Henningsson Date: Tue, 24 Mar 2015 10:29:14 +0100 Subject: [PATCH] lfe-filter: Cleanup and refactor - Remove imported dead code - Fix compiler warnings - Fix non-GCC compiler compilation (use more portable macros) - Change lr4 struct to include a biquad struct Thanks to Alexander Patrakov for suggesting many of these changes. Signed-off-by: David Henningsson --- src/pulsecore/filter/biquad.c | 289 +++------------------------------------ src/pulsecore/filter/biquad.h | 14 +- src/pulsecore/filter/crossover.c | 194 ++------------------------ src/pulsecore/filter/crossover.h | 51 +------ 4 files changed, 33 insertions(+), 515 deletions(-) diff --git a/src/pulsecore/filter/biquad.c b/src/pulsecore/filter/biquad.c index b28256d..7c21a29 100644 --- a/src/pulsecore/filter/biquad.c +++ b/src/pulsecore/filter/biquad.c @@ -8,20 +8,15 @@ * found in the LICENSE.WEBKIT file. */ -#include -#include "biquad.h" -#ifndef max -#define max(a, b) ({ __typeof__(a) _a = (a); \ - __typeof__(b) _b = (b); \ - _a > _b ? _a : _b; }) +#ifdef HAVE_CONFIG_H +#include #endif -#ifndef min -#define min(a, b) ({ __typeof__(a) _a = (a); \ - __typeof__(b) _b = (b); \ - _a < _b ? _a : _b; }) -#endif +#include + +#include +#include "biquad.h" #ifndef M_PI #define M_PI 3.14159265358979323846 @@ -38,19 +33,18 @@ static void set_coefficient(struct biquad *bq, double b0, double b1, double b2, bq->a2 = a2 * a0_inv; } -static void biquad_lowpass(struct biquad *bq, double cutoff, double resonance) +static void biquad_lowpass(struct biquad *bq, double cutoff) { /* Limit cutoff to 0 to 1. */ - cutoff = max(0.0, min(cutoff, 1.0)); + cutoff = PA_MIN(cutoff, 1.0); + cutoff = PA_MAX(0.0, cutoff); - if (cutoff == 1) { + if (cutoff >= 1.0) { /* When cutoff is 1, the z-transform is 1. */ set_coefficient(bq, 1, 0, 0, 1, 0, 0); } else if (cutoff > 0) { /* Compute biquad coefficients for lowpass filter */ - resonance = max(0.0, resonance); /* can't go negative */ - double g = pow(10.0, 0.05 * resonance); - double d = sqrt((4 - sqrt(16 - 16 / (g * g))) / 2); + double d = sqrt(2); double theta = M_PI * cutoff; double sn = 0.5 * d * sin(theta); @@ -73,19 +67,18 @@ static void biquad_lowpass(struct biquad *bq, double cutoff, double resonance) } } -static void biquad_highpass(struct biquad *bq, double cutoff, double resonance) +static void biquad_highpass(struct biquad *bq, double cutoff) { /* Limit cutoff to 0 to 1. */ - cutoff = max(0.0, min(cutoff, 1.0)); + cutoff = PA_MIN(cutoff, 1.0); + cutoff = PA_MAX(0.0, cutoff); - if (cutoff == 1) { + if (cutoff >= 1.0) { /* The z-transform is 0. */ set_coefficient(bq, 0, 0, 0, 1, 0, 0); } else if (cutoff > 0) { /* Compute biquad coefficients for highpass filter */ - resonance = max(0.0, resonance); /* can't go negative */ - double g = pow(10.0, 0.05 * resonance); - double d = sqrt((4 - sqrt(16 - 16 / (g * g))) / 2); + double d = sqrt(2); double theta = M_PI * cutoff; double sn = 0.5 * d * sin(theta); @@ -110,259 +103,15 @@ static void biquad_highpass(struct biquad *bq, double cutoff, double resonance) } } -static void biquad_bandpass(struct biquad *bq, double frequency, double Q) -{ - /* No negative frequencies allowed. */ - frequency = max(0.0, frequency); - - /* Don't let Q go negative, which causes an unstable filter. */ - Q = max(0.0, Q); - - if (frequency > 0 && frequency < 1) { - double w0 = M_PI * frequency; - if (Q > 0) { - double alpha = sin(w0) / (2 * Q); - double k = cos(w0); - - double b0 = alpha; - double b1 = 0; - double b2 = -alpha; - double a0 = 1 + alpha; - double a1 = -2 * k; - double a2 = 1 - alpha; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When Q = 0, the above formulas have problems. If we - * look at the z-transform, we can see that the limit - * as Q->0 is 1, so set the filter that way. - */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } - } else { - /* When the cutoff is zero, the z-transform approaches 0, if Q - * > 0. When both Q and cutoff are zero, the z-transform is - * pretty much undefined. What should we do in this case? - * For now, just make the filter 0. When the cutoff is 1, the - * z-transform also approaches 0. - */ - set_coefficient(bq, 0, 0, 0, 1, 0, 0); - } -} - -static void biquad_lowshelf(struct biquad *bq, double frequency, double db_gain) -{ - /* Clip frequencies to between 0 and 1, inclusive. */ - frequency = max(0.0, min(frequency, 1.0)); - - double A = pow(10.0, db_gain / 40); - - if (frequency == 1) { - /* The z-transform is a constant gain. */ - set_coefficient(bq, A * A, 0, 0, 1, 0, 0); - } else if (frequency > 0) { - double w0 = M_PI * frequency; - double S = 1; /* filter slope (1 is max value) */ - double alpha = 0.5 * sin(w0) * - sqrt((A + 1 / A) * (1 / S - 1) + 2); - double k = cos(w0); - double k2 = 2 * sqrt(A) * alpha; - double a_plus_one = A + 1; - double a_minus_one = A - 1; - - double b0 = A * (a_plus_one - a_minus_one * k + k2); - double b1 = 2 * A * (a_minus_one - a_plus_one * k); - double b2 = A * (a_plus_one - a_minus_one * k - k2); - double a0 = a_plus_one + a_minus_one * k + k2; - double a1 = -2 * (a_minus_one + a_plus_one * k); - double a2 = a_plus_one + a_minus_one * k - k2; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When frequency is 0, the z-transform is 1. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } -} - -static void biquad_highshelf(struct biquad *bq, double frequency, - double db_gain) +void biquad_set(struct biquad *bq, enum biquad_type type, double freq) { - /* Clip frequencies to between 0 and 1, inclusive. */ - frequency = max(0.0, min(frequency, 1.0)); - - double A = pow(10.0, db_gain / 40); - - if (frequency == 1) { - /* The z-transform is 1. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } else if (frequency > 0) { - double w0 = M_PI * frequency; - double S = 1; /* filter slope (1 is max value) */ - double alpha = 0.5 * sin(w0) * - sqrt((A + 1 / A) * (1 / S - 1) + 2); - double k = cos(w0); - double k2 = 2 * sqrt(A) * alpha; - double a_plus_one = A + 1; - double a_minus_one = A - 1; - - double b0 = A * (a_plus_one + a_minus_one * k + k2); - double b1 = -2 * A * (a_minus_one + a_plus_one * k); - double b2 = A * (a_plus_one + a_minus_one * k - k2); - double a0 = a_plus_one - a_minus_one * k + k2; - double a1 = 2 * (a_minus_one - a_plus_one * k); - double a2 = a_plus_one - a_minus_one * k - k2; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When frequency = 0, the filter is just a gain, A^2. */ - set_coefficient(bq, A * A, 0, 0, 1, 0, 0); - } -} - -static void biquad_peaking(struct biquad *bq, double frequency, double Q, - double db_gain) -{ - /* Clip frequencies to between 0 and 1, inclusive. */ - frequency = max(0.0, min(frequency, 1.0)); - - /* Don't let Q go negative, which causes an unstable filter. */ - Q = max(0.0, Q); - - double A = pow(10.0, db_gain / 40); - - if (frequency > 0 && frequency < 1) { - if (Q > 0) { - double w0 = M_PI * frequency; - double alpha = sin(w0) / (2 * Q); - double k = cos(w0); - - double b0 = 1 + alpha * A; - double b1 = -2 * k; - double b2 = 1 - alpha * A; - double a0 = 1 + alpha / A; - double a1 = -2 * k; - double a2 = 1 - alpha / A; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When Q = 0, the above formulas have problems. If we - * look at the z-transform, we can see that the limit - * as Q->0 is A^2, so set the filter that way. - */ - set_coefficient(bq, A * A, 0, 0, 1, 0, 0); - } - } else { - /* When frequency is 0 or 1, the z-transform is 1. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } -} - -static void biquad_notch(struct biquad *bq, double frequency, double Q) -{ - /* Clip frequencies to between 0 and 1, inclusive. */ - frequency = max(0.0, min(frequency, 1.0)); - - /* Don't let Q go negative, which causes an unstable filter. */ - Q = max(0.0, Q); - - if (frequency > 0 && frequency < 1) { - if (Q > 0) { - double w0 = M_PI * frequency; - double alpha = sin(w0) / (2 * Q); - double k = cos(w0); - - double b0 = 1; - double b1 = -2 * k; - double b2 = 1; - double a0 = 1 + alpha; - double a1 = -2 * k; - double a2 = 1 - alpha; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When Q = 0, the above formulas have problems. If we - * look at the z-transform, we can see that the limit - * as Q->0 is 0, so set the filter that way. - */ - set_coefficient(bq, 0, 0, 0, 1, 0, 0); - } - } else { - /* When frequency is 0 or 1, the z-transform is 1. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } -} - -static void biquad_allpass(struct biquad *bq, double frequency, double Q) -{ - /* Clip frequencies to between 0 and 1, inclusive. */ - frequency = max(0.0, min(frequency, 1.0)); - - /* Don't let Q go negative, which causes an unstable filter. */ - Q = max(0.0, Q); - - if (frequency > 0 && frequency < 1) { - if (Q > 0) { - double w0 = M_PI * frequency; - double alpha = sin(w0) / (2 * Q); - double k = cos(w0); - - double b0 = 1 - alpha; - double b1 = -2 * k; - double b2 = 1 + alpha; - double a0 = 1 + alpha; - double a1 = -2 * k; - double a2 = 1 - alpha; - - set_coefficient(bq, b0, b1, b2, a0, a1, a2); - } else { - /* When Q = 0, the above formulas have problems. If we - * look at the z-transform, we can see that the limit - * as Q->0 is -1, so set the filter that way. - */ - set_coefficient(bq, -1, 0, 0, 1, 0, 0); - } - } else { - /* When frequency is 0 or 1, the z-transform is 1. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - } -} - -void biquad_set(struct biquad *bq, enum biquad_type type, double freq, double Q, - double gain) -{ - /* Default is an identity filter. Also clear history values. */ - set_coefficient(bq, 1, 0, 0, 1, 0, 0); - bq->x1 = 0; - bq->x2 = 0; - bq->y1 = 0; - bq->y2 = 0; switch (type) { case BQ_LOWPASS: - biquad_lowpass(bq, freq, Q); + biquad_lowpass(bq, freq); break; case BQ_HIGHPASS: - biquad_highpass(bq, freq, Q); - break; - case BQ_BANDPASS: - biquad_bandpass(bq, freq, Q); - break; - case BQ_LOWSHELF: - biquad_lowshelf(bq, freq, gain); - break; - case BQ_HIGHSHELF: - biquad_highshelf(bq, freq, gain); - break; - case BQ_PEAKING: - biquad_peaking(bq, freq, Q, gain); - break; - case BQ_NOTCH: - biquad_notch(bq, freq, Q); - break; - case BQ_ALLPASS: - biquad_allpass(bq, freq, Q); - break; - case BQ_NONE: + biquad_highpass(bq, freq); break; } } diff --git a/src/pulsecore/filter/biquad.h b/src/pulsecore/filter/biquad.h index c584aa9..bb8f2fb 100644 --- a/src/pulsecore/filter/biquad.h +++ b/src/pulsecore/filter/biquad.h @@ -21,21 +21,12 @@ extern "C" { struct biquad { float b0, b1, b2; float a1, a2; - float x1, x2; - float y1, y2; }; /* The type of the biquad filters */ enum biquad_type { - BQ_NONE, BQ_LOWPASS, BQ_HIGHPASS, - BQ_BANDPASS, - BQ_LOWSHELF, - BQ_HIGHSHELF, - BQ_PEAKING, - BQ_NOTCH, - BQ_ALLPASS }; /* Initialize a biquad filter parameters from its type and parameters. @@ -44,11 +35,8 @@ enum biquad_type { * type - The type of the biquad filter. * frequency - The value should be in the range [0, 1]. It is relative to * half of the sampling rate. - * Q - Quality factor. See Web Audio API for details. - * gain - The value is in dB. See Web Audio API for details. */ -void biquad_set(struct biquad *bq, enum biquad_type type, double freq, double Q, - double gain); +void biquad_set(struct biquad *bq, enum biquad_type type, double freq); #ifdef __cplusplus } /* extern "C" */ diff --git a/src/pulsecore/filter/crossover.c b/src/pulsecore/filter/crossover.c index 0a571c3..dab34af 100644 --- a/src/pulsecore/filter/crossover.c +++ b/src/pulsecore/filter/crossover.c @@ -9,18 +9,11 @@ #include -#include "biquad.h" #include "crossover.h" void lr4_set(struct lr4 *lr4, enum biquad_type type, float freq) { - struct biquad q; - biquad_set(&q, type, freq, 0, 0); - lr4->b0 = q.b0; - lr4->b1 = q.b1; - lr4->b2 = q.b2; - lr4->a1 = q.a1; - lr4->a2 = q.a2; + biquad_set(&lr4->bq, type, freq); lr4->x1 = 0; lr4->x2 = 0; lr4->y1 = 0; @@ -37,11 +30,11 @@ void lr4_process_float32(struct lr4 *lr4, int samples, int channels, float *src, float ly2 = lr4->y2; float lz1 = lr4->z1; float lz2 = lr4->z2; - float lb0 = lr4->b0; - float lb1 = lr4->b1; - float lb2 = lr4->b2; - float la1 = lr4->a1; - float la2 = lr4->a2; + float lb0 = lr4->bq.b0; + float lb1 = lr4->bq.b1; + float lb2 = lr4->bq.b2; + float la1 = lr4->bq.a1; + float la2 = lr4->bq.a2; int i; for (i = 0; i < samples * channels; i += channels) { @@ -74,11 +67,11 @@ void lr4_process_s16(struct lr4 *lr4, int samples, int channels, short *src, sho float ly2 = lr4->y2; float lz1 = lr4->z1; float lz2 = lr4->z2; - float lb0 = lr4->b0; - float lb1 = lr4->b1; - float lb2 = lr4->b2; - float la1 = lr4->a1; - float la2 = lr4->a2; + float lb0 = lr4->bq.b0; + float lb1 = lr4->bq.b1; + float lb2 = lr4->bq.b2; + float la1 = lr4->bq.a1; + float la2 = lr4->bq.a2; int i; for (i = 0; i < samples * channels; i += channels) { @@ -102,168 +95,3 @@ void lr4_process_s16(struct lr4 *lr4, int samples, int channels, short *src, sho lr4->z1 = lz1; lr4->z2 = lz2; } - - -/* Split input data using two LR4 filters, put the result into the input array - * and another array. - * - * data0 --+-- lp --> data0 - * | - * \-- hp --> data1 - */ -static void lr4_split(struct lr4 *lp, struct lr4 *hp, int count, float *data0, - float *data1) -{ - float lx1 = lp->x1; - float lx2 = lp->x2; - float ly1 = lp->y1; - float ly2 = lp->y2; - float lz1 = lp->z1; - float lz2 = lp->z2; - float lb0 = lp->b0; - float lb1 = lp->b1; - float lb2 = lp->b2; - float la1 = lp->a1; - float la2 = lp->a2; - - float hx1 = hp->x1; - float hx2 = hp->x2; - float hy1 = hp->y1; - float hy2 = hp->y2; - float hz1 = hp->z1; - float hz2 = hp->z2; - float hb0 = hp->b0; - float hb1 = hp->b1; - float hb2 = hp->b2; - float ha1 = hp->a1; - float ha2 = hp->a2; - - int i; - for (i = 0; i < count; i++) { - float x, y, z; - x = data0[i]; - y = lb0*x + lb1*lx1 + lb2*lx2 - la1*ly1 - la2*ly2; - z = lb0*y + lb1*ly1 + lb2*ly2 - la1*lz1 - la2*lz2; - lx2 = lx1; - lx1 = x; - ly2 = ly1; - ly1 = y; - lz2 = lz1; - lz1 = z; - data0[i] = z; - - y = hb0*x + hb1*hx1 + hb2*hx2 - ha1*hy1 - ha2*hy2; - z = hb0*y + hb1*hy1 + hb2*hy2 - ha1*hz1 - ha2*hz2; - hx2 = hx1; - hx1 = x; - hy2 = hy1; - hy1 = y; - hz2 = hz1; - hz1 = z; - data1[i] = z; - } - - lp->x1 = lx1; - lp->x2 = lx2; - lp->y1 = ly1; - lp->y2 = ly2; - lp->z1 = lz1; - lp->z2 = lz2; - - hp->x1 = hx1; - hp->x2 = hx2; - hp->y1 = hy1; - hp->y2 = hy2; - hp->z1 = hz1; - hp->z2 = hz2; -} - -/* Split input data using two LR4 filters and sum them back to the original - * data array. - * - * data --+-- lp --+--> data - * | | - * \-- hp --/ - */ -static void lr4_merge(struct lr4 *lp, struct lr4 *hp, int count, float *data) -{ - float lx1 = lp->x1; - float lx2 = lp->x2; - float ly1 = lp->y1; - float ly2 = lp->y2; - float lz1 = lp->z1; - float lz2 = lp->z2; - float lb0 = lp->b0; - float lb1 = lp->b1; - float lb2 = lp->b2; - float la1 = lp->a1; - float la2 = lp->a2; - - float hx1 = hp->x1; - float hx2 = hp->x2; - float hy1 = hp->y1; - float hy2 = hp->y2; - float hz1 = hp->z1; - float hz2 = hp->z2; - float hb0 = hp->b0; - float hb1 = hp->b1; - float hb2 = hp->b2; - float ha1 = hp->a1; - float ha2 = hp->a2; - - int i; - for (i = 0; i < count; i++) { - float x, y, z; - x = data[i]; - y = lb0*x + lb1*lx1 + lb2*lx2 - la1*ly1 - la2*ly2; - z = lb0*y + lb1*ly1 + lb2*ly2 - la1*lz1 - la2*lz2; - lx2 = lx1; - lx1 = x; - ly2 = ly1; - ly1 = y; - lz2 = lz1; - lz1 = z; - - y = hb0*x + hb1*hx1 + hb2*hx2 - ha1*hy1 - ha2*hy2; - z = hb0*y + hb1*hy1 + hb2*hy2 - ha1*hz1 - ha2*hz2; - hx2 = hx1; - hx1 = x; - hy2 = hy1; - hy1 = y; - hz2 = hz1; - hz1 = z; - data[i] = z + lz1; - } - - lp->x1 = lx1; - lp->x2 = lx2; - lp->y1 = ly1; - lp->y2 = ly2; - lp->z1 = lz1; - lp->z2 = lz2; - - hp->x1 = hx1; - hp->x2 = hx2; - hp->y1 = hy1; - hp->y2 = hy2; - hp->z1 = hz1; - hp->z2 = hz2; -} - -void crossover_init(struct crossover *xo, float freq1, float freq2) -{ - int i; - for (i = 0; i < 3; i++) { - float f = (i == 0) ? freq1 : freq2; - lr4_set(&xo->lp[i], BQ_LOWPASS, f); - lr4_set(&xo->hp[i], BQ_HIGHPASS, f); - } -} - -void crossover_process(struct crossover *xo, int count, float *data0, - float *data1, float *data2) -{ - lr4_split(&xo->lp[0], &xo->hp[0], count, data0, data1); - lr4_merge(&xo->lp[1], &xo->hp[1], count, data0); - lr4_split(&xo->lp[2], &xo->hp[2], count, data1, data2); -} diff --git a/src/pulsecore/filter/crossover.h b/src/pulsecore/filter/crossover.h index a88f5b6..c5c9765 100644 --- a/src/pulsecore/filter/crossover.h +++ b/src/pulsecore/filter/crossover.h @@ -6,10 +6,7 @@ #ifndef CROSSOVER_H_ #define CROSSOVER_H_ -#ifdef __cplusplus -extern "C" { -#endif - +#include "biquad.h" /* An LR4 filter is two biquads with the same parameters connected in series: * * x -- [BIQUAD] -- y -- [BIQUAD] -- z @@ -18,8 +15,7 @@ extern "C" { * The variable [xyz][12] keep the history values. */ struct lr4 { - float b0, b1, b2; - float a1, a2; + struct biquad bq; float x1, x2; float y1, y2; float z1, z2; @@ -30,47 +26,4 @@ void lr4_set(struct lr4 *lr4, enum biquad_type type, float freq); void lr4_process_float32(struct lr4 *lr4, int samples, int channels, float *src, float *dest); void lr4_process_s16(struct lr4 *lr4, int samples, int channels, short *src, short *dest); - -/* Three bands crossover filter: - * - * INPUT --+-- lp0 --+-- lp1 --+---> LOW (0) - * | | | - * | \-- hp1 --/ - * | - * \-- hp0 --+-- lp2 ------> MID (1) - * | - * \-- hp2 ------> HIGH (2) - * - * [f0] [f1] - * - * Each lp or hp is an LR4 filter, which consists of two second-order - * lowpass or highpass butterworth filters. - */ -struct crossover { - struct lr4 lp[3], hp[3]; -}; - -/* Initializes a crossover filter - * Args: - * xo - The crossover filter we want to initialize. - * freq1 - The normalized frequency splits low and mid band. - * freq2 - The normalized frequency splits mid and high band. - */ -void crossover_init(struct crossover *xo, float freq1, float freq2); - -/* Splits input samples to three bands. - * Args: - * xo - The crossover filter to use. - * count - The number of input samples. - * data0 - The input samples, also the place to store low band output. - * data1 - The place to store mid band output. - * data2 - The place to store high band output. - */ -void crossover_process(struct crossover *xo, int count, float *data0, - float *data1, float *data2); - -#ifdef __cplusplus -} /* extern "C" */ -#endif - #endif /* CROSSOVER_H_ */ -- 2.7.4