[pulseaudio-discuss] [PATCH 3/7] lfe-filter: Cleanup and refactor
David Henningsson
david.henningsson at canonical.com
Tue Feb 17 04:29:20 PST 2015
- 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 <david.henningsson at canonical.com>
---
src/pulsecore/filter/biquad.c | 278 +++------------------------------------
src/pulsecore/filter/biquad.h | 8 --
src/pulsecore/filter/crossover.c | 194 ++-------------------------
src/pulsecore/filter/crossover.h | 51 +------
4 files changed, 31 insertions(+), 500 deletions(-)
diff --git a/src/pulsecore/filter/biquad.c b/src/pulsecore/filter/biquad.c
index b28256d..a6121f4 100644
--- a/src/pulsecore/filter/biquad.c
+++ b/src/pulsecore/filter/biquad.c
@@ -8,20 +8,15 @@
* found in the LICENSE.WEBKIT file.
*/
-#include <math.h>
-#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 <config.h>
#endif
-#ifndef min
-#define min(a, b) ({ __typeof__(a) _a = (a); \
- __typeof__(b) _b = (b); \
- _a < _b ? _a : _b; })
-#endif
+#include <pulsecore/macro.h>
+
+#include <math.h>
+#include "biquad.h"
#ifndef M_PI
#define M_PI 3.14159265358979323846
@@ -41,15 +36,16 @@ static void set_coefficient(struct biquad *bq, double b0, double b1, double b2,
static void biquad_lowpass(struct biquad *bq, double cutoff, double resonance)
{
/* 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 r = PA_MAX(0.0, resonance); /* can't go negative */
+ double g = pow(10.0, 0.05 * r);
double d = sqrt((4 - sqrt(16 - 16 / (g * g))) / 2);
double theta = M_PI * cutoff;
@@ -76,15 +72,16 @@ static void biquad_lowpass(struct biquad *bq, double cutoff, double resonance)
static void biquad_highpass(struct biquad *bq, double cutoff, double resonance)
{
/* 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 r = PA_MAX(0.0, resonance); /* can't go negative */
+ double g = pow(10.0, 0.05 * r);
double d = sqrt((4 - sqrt(16 - 16 / (g * g))) / 2);
double theta = M_PI * cutoff;
@@ -110,232 +107,9 @@ 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)
-{
- /* 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:
@@ -344,25 +118,9 @@ void biquad_set(struct biquad *bq, enum biquad_type type, double freq, double Q,
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:
+ /* Identity filter. */
+ set_coefficient(bq, 1, 0, 0, 1, 0, 0);
break;
}
}
diff --git a/src/pulsecore/filter/biquad.h b/src/pulsecore/filter/biquad.h
index c584aa9..4a84b61 100644
--- a/src/pulsecore/filter/biquad.h
+++ b/src/pulsecore/filter/biquad.h
@@ -21,8 +21,6 @@ extern "C" {
struct biquad {
float b0, b1, b2;
float a1, a2;
- float x1, x2;
- float y1, y2;
};
/* The type of the biquad filters */
@@ -30,12 +28,6 @@ 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.
diff --git a/src/pulsecore/filter/crossover.c b/src/pulsecore/filter/crossover.c
index 6a817d4..c2a584b 100644
--- a/src/pulsecore/filter/crossover.c
+++ b/src/pulsecore/filter/crossover.c
@@ -9,18 +9,11 @@
#include <pulsecore/macro.h>
-#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, 0, 0);
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; 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; 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_ */
--
1.9.1
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