* different IIR filters implementation
*/
-#include "iirfilter.h"
#include <math.h>
+#include "libavutil/attributes.h"
+#include "libavutil/common.h"
+#include "libavutil/log.h"
+
+#include "iirfilter.h"
+
/**
* IIR filter global parameters
*/
-typedef struct FFIIRFilterCoeffs{
+typedef struct FFIIRFilterCoeffs {
int order;
float gain;
int *cx;
float *cy;
-}FFIIRFilterCoeffs;
+} FFIIRFilterCoeffs;
/**
* IIR filter state
*/
-typedef struct FFIIRFilterState{
+typedef struct FFIIRFilterState {
float x[1];
-}FFIIRFilterState;
+} FFIIRFilterState;
/// maximum supported filter order
#define MAXORDER 30
-static int butterworth_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
- enum IIRFilterMode filt_mode,
- int order, float cutoff_ratio,
- float stopband)
+static av_cold int butterworth_init_coeffs(void *avc,
+ struct FFIIRFilterCoeffs *c,
+ enum IIRFilterMode filt_mode,
+ int order, float cutoff_ratio,
+ float stopband)
{
int i, j;
double wa;
if (filt_mode != FF_FILTER_MODE_LOWPASS) {
av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports "
- "low-pass filter mode\n");
+ "low-pass filter mode\n");
return -1;
}
if (order & 1) {
av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports "
- "even filter orders\n");
+ "even filter orders\n");
return -1;
}
wa = 2 * tan(M_PI * 0.5 * cutoff_ratio);
c->cx[0] = 1;
- for(i = 1; i < (order >> 1) + 1; i++)
+ for (i = 1; i < (order >> 1) + 1; i++)
c->cx[i] = c->cx[i - 1] * (order - i + 1LL) / i;
p[0][0] = 1.0;
p[0][1] = 0.0;
- for(i = 1; i <= order; i++)
+ for (i = 1; i <= order; i++)
p[i][0] = p[i][1] = 0.0;
- for(i = 0; i < order; i++){
+ for (i = 0; i < order; i++) {
double zp[2];
double th = (i + (order >> 1) + 0.5) * M_PI / order;
double a_re, a_im, c_re, c_im;
zp[0] = cos(th) * wa;
zp[1] = sin(th) * wa;
- a_re = zp[0] + 2.0;
- c_re = zp[0] - 2.0;
- a_im =
- c_im = zp[1];
+ a_re = zp[0] + 2.0;
+ c_re = zp[0] - 2.0;
+ a_im =
+ c_im = zp[1];
zp[0] = (a_re * c_re + a_im * c_im) / (c_re * c_re + c_im * c_im);
zp[1] = (a_im * c_re - a_re * c_im) / (c_re * c_re + c_im * c_im);
- for(j = order; j >= 1; j--)
- {
- a_re = p[j][0];
- a_im = p[j][1];
- p[j][0] = a_re*zp[0] - a_im*zp[1] + p[j-1][0];
- p[j][1] = a_re*zp[1] + a_im*zp[0] + p[j-1][1];
+ for (j = order; j >= 1; j--) {
+ a_re = p[j][0];
+ a_im = p[j][1];
+ p[j][0] = a_re * zp[0] - a_im * zp[1] + p[j - 1][0];
+ p[j][1] = a_re * zp[1] + a_im * zp[0] + p[j - 1][1];
}
- a_re = p[0][0]*zp[0] - p[0][1]*zp[1];
- p[0][1] = p[0][0]*zp[1] + p[0][1]*zp[0];
+ a_re = p[0][0] * zp[0] - p[0][1] * zp[1];
+ p[0][1] = p[0][0] * zp[1] + p[0][1] * zp[0];
p[0][0] = a_re;
}
c->gain = p[order][0];
- for(i = 0; i < order; i++){
+ for (i = 0; i < order; i++) {
c->gain += p[i][0];
c->cy[i] = (-p[i][0] * p[order][0] + -p[i][1] * p[order][1]) /
(p[order][0] * p[order][0] + p[order][1] * p[order][1]);
return 0;
}
-static int biquad_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
- enum IIRFilterMode filt_mode, int order,
- float cutoff_ratio, float stopband)
+static av_cold int biquad_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
+ enum IIRFilterMode filt_mode, int order,
+ float cutoff_ratio, float stopband)
{
double cos_w0, sin_w0;
double a0, x0, x1;
if (filt_mode != FF_FILTER_MODE_HIGHPASS &&
filt_mode != FF_FILTER_MODE_LOWPASS) {
av_log(avc, AV_LOG_ERROR, "Biquad filter currently only supports "
- "high-pass and low-pass filter modes\n");
+ "high-pass and low-pass filter modes\n");
return -1;
}
if (order != 2) {
return 0;
}
-av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(void *avc,
- enum IIRFilterType filt_type,
- enum IIRFilterMode filt_mode,
- int order, float cutoff_ratio,
- float stopband, float ripple)
+av_cold struct FFIIRFilterCoeffs *ff_iir_filter_init_coeffs(void *avc,
+ enum IIRFilterType filt_type,
+ enum IIRFilterMode filt_mode,
+ int order, float cutoff_ratio,
+ float stopband, float ripple)
{
FFIIRFilterCoeffs *c;
int ret = 0;
if (order <= 0 || order > MAXORDER || cutoff_ratio >= 1.0)
return NULL;
- FF_ALLOCZ_OR_GOTO(avc, c, sizeof(FFIIRFilterCoeffs),
- init_fail);
- FF_ALLOC_OR_GOTO (avc, c->cx, sizeof(c->cx[0]) * ((order >> 1) + 1),
- init_fail);
- FF_ALLOC_OR_GOTO (avc, c->cy, sizeof(c->cy[0]) * order,
+ FF_ALLOCZ_OR_GOTO(avc, c, sizeof(FFIIRFilterCoeffs),
init_fail);
+ FF_ALLOC_OR_GOTO(avc, c->cx, sizeof(c->cx[0]) * ((order >> 1) + 1),
+ init_fail);
+ FF_ALLOC_OR_GOTO(avc, c->cy, sizeof(c->cy[0]) * order,
+ init_fail);
c->order = order;
switch (filt_type) {
return NULL;
}
-av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
+av_cold struct FFIIRFilterState *ff_iir_filter_init_state(int order)
{
- FFIIRFilterState* s = av_mallocz(sizeof(FFIIRFilterState) + sizeof(s->x[0]) * (order - 1));
+ FFIIRFilterState *s = av_mallocz(sizeof(FFIIRFilterState) + sizeof(s->x[0]) * (order - 1));
return s;
}
#define CONV_FLT(dest, source) dest = source;
-#define FILTER_BW_O4_1(i0, i1, i2, i3, fmt) \
- in = *src0 * c->gain \
- + c->cy[0]*s->x[i0] + c->cy[1]*s->x[i1] \
- + c->cy[2]*s->x[i2] + c->cy[3]*s->x[i3]; \
- res = (s->x[i0] + in )*1 \
- + (s->x[i1] + s->x[i3])*4 \
- + s->x[i2] *6; \
- CONV_##fmt(*dst0, res) \
- s->x[i0] = in; \
- src0 += sstep; \
- dst0 += dstep;
+#define FILTER_BW_O4_1(i0, i1, i2, i3, fmt) \
+ in = *src0 * c->gain + \
+ c->cy[0] * s->x[i0] + \
+ c->cy[1] * s->x[i1] + \
+ c->cy[2] * s->x[i2] + \
+ c->cy[3] * s->x[i3]; \
+ res = (s->x[i0] + in) * 1 + \
+ (s->x[i1] + s->x[i3]) * 4 + \
+ s->x[i2] * 6; \
+ CONV_ ## fmt(*dst0, res) \
+ s->x[i0] = in; \
+ src0 += sstep; \
+ dst0 += dstep;
#define FILTER_BW_O4(type, fmt) { \
int i; \
int j; \
float in, res; \
in = *src0 * c->gain; \
- for(j = 0; j < c->order; j++) \
+ for (j = 0; j < c->order; j++) \
in += c->cy[j] * s->x[j]; \
res = s->x[0] + in + s->x[c->order >> 1] * c->cx[c->order >> 1]; \
- for(j = 1; j < c->order >> 1; j++) \
+ for (j = 1; j < c->order >> 1; j++) \
res += (s->x[j] + s->x[c->order - j]) * c->cx[j]; \
- for(j = 0; j < c->order - 1; j++) \
+ for (j = 0; j < c->order - 1; j++) \
s->x[j] = s->x[j + 1]; \
- CONV_##fmt(*dst0, res) \
+ CONV_ ## fmt(*dst0, res) \
s->x[c->order - 1] = in; \
- src0 += sstep; \
- dst0 += dstep; \
+ src0 += sstep; \
+ dst0 += dstep; \
} \
}
float in = *src0 * c->gain + \
s->x[0] * c->cy[0] + \
s->x[1] * c->cy[1]; \
- CONV_##fmt(*dst0, s->x[0] + in + s->x[1] * c->cx[1]) \
+ CONV_ ## fmt(*dst0, s->x[0] + in + s->x[1] * c->cx[1]) \
s->x[0] = s->x[1]; \
s->x[1] = in; \
- src0 += sstep; \
- dst0 += dstep; \
+ src0 += sstep; \
+ dst0 += dstep; \
} \
}
void ff_iir_filter(const struct FFIIRFilterCoeffs *c,
struct FFIIRFilterState *s, int size,
- const int16_t *src, int sstep, int16_t *dst, int dstep)
+ const int16_t *src, ptrdiff_t sstep,
+ int16_t *dst, ptrdiff_t dstep)
{
if (c->order == 2) {
FILTER_O2(int16_t, S16)
void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
struct FFIIRFilterState *s, int size,
- const float *src, int sstep, float *dst, int dstep)
+ const float *src, ptrdiff_t sstep,
+ float *dst, ptrdiff_t dstep)
{
if (c->order == 2) {
FILTER_O2(float, FLT)
av_cold void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
{
- if(coeffs){
+ if (coeffs) {
av_free(coeffs->cx);
av_free(coeffs->cy);
}
av_free(coeffs);
}
-
-#ifdef TEST
-#undef printf
-#include <stdio.h>
-
-#define FILT_ORDER 4
-#define SIZE 1024
-int main(void)
-{
- struct FFIIRFilterCoeffs *fcoeffs = NULL;
- struct FFIIRFilterState *fstate = NULL;
- float cutoff_coeff = 0.4;
- int16_t x[SIZE], y[SIZE];
- int i;
-
- fcoeffs = ff_iir_filter_init_coeffs(NULL, FF_FILTER_TYPE_BUTTERWORTH,
- FF_FILTER_MODE_LOWPASS, FILT_ORDER,
- cutoff_coeff, 0.0, 0.0);
- fstate = ff_iir_filter_init_state(FILT_ORDER);
-
- for (i = 0; i < SIZE; i++) {
- x[i] = lrint(0.75 * INT16_MAX * sin(0.5*M_PI*i*i/SIZE));
- }
-
- ff_iir_filter(fcoeffs, fstate, SIZE, x, 1, y, 1);
-
- for (i = 0; i < SIZE; i++)
- printf("%6d %6d\n", x[i], y[i]);
-
- ff_iir_filter_free_coeffs(fcoeffs);
- ff_iir_filter_free_state(fstate);
- return 0;
-}
-#endif /* TEST */
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