| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * IIR filter | ||
| 3 | * Copyright (c) 2008 Konstantin Shishkov | ||
| 4 | * | ||
| 5 | * This file is part of FFmpeg. | ||
| 6 | * | ||
| 7 | * FFmpeg is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with FFmpeg; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | */ | ||
| 21 | |||
| 22 | /** | ||
| 23 | * @file | ||
| 24 | * different IIR filters implementation | ||
| 25 | */ | ||
| 26 | |||
| 27 | #include <math.h> | ||
| 28 | |||
| 29 | #include "libavutil/attributes.h" | ||
| 30 | #include "libavutil/common.h" | ||
| 31 | |||
| 32 | #include "iirfilter.h" | ||
| 33 | |||
| 34 | /** | ||
| 35 | * IIR filter global parameters | ||
| 36 | */ | ||
| 37 | typedef struct FFIIRFilterCoeffs { | ||
| 38 | int order; | ||
| 39 | float gain; | ||
| 40 | int *cx; | ||
| 41 | float *cy; | ||
| 42 | } FFIIRFilterCoeffs; | ||
| 43 | |||
| 44 | /** | ||
| 45 | * IIR filter state | ||
| 46 | */ | ||
| 47 | typedef struct FFIIRFilterState { | ||
| 48 | float x[1]; | ||
| 49 | } FFIIRFilterState; | ||
| 50 | |||
| 51 | /// maximum supported filter order | ||
| 52 | #define MAXORDER 30 | ||
| 53 | |||
| 54 | 1 | static av_cold int butterworth_init_coeffs(void *avc, | |
| 55 | struct FFIIRFilterCoeffs *c, | ||
| 56 | enum IIRFilterMode filt_mode, | ||
| 57 | int order, float cutoff_ratio, | ||
| 58 | float stopband) | ||
| 59 | { | ||
| 60 | int i, j; | ||
| 61 | double wa; | ||
| 62 | double p[MAXORDER + 1][2]; | ||
| 63 | |||
| 64 |
1/2✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
|
1 | if (filt_mode != FF_FILTER_MODE_LOWPASS) { |
| 65 | ✗ | av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports " | |
| 66 | "low-pass filter mode\n"); | ||
| 67 | ✗ | return -1; | |
| 68 | } | ||
| 69 |
1/2✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
|
1 | if (order & 1) { |
| 70 | ✗ | av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports " | |
| 71 | "even filter orders\n"); | ||
| 72 | ✗ | return -1; | |
| 73 | } | ||
| 74 | |||
| 75 | 1 | wa = 2 * tan(M_PI * 0.5 * cutoff_ratio); | |
| 76 | |||
| 77 | 1 | c->cx[0] = 1; | |
| 78 |
2/2✓ Branch 0 taken 2 times.
✓ Branch 1 taken 1 times.
|
3 | for (i = 1; i < (order >> 1) + 1; i++) |
| 79 | 2 | c->cx[i] = c->cx[i - 1] * (order - i + 1LL) / i; | |
| 80 | |||
| 81 | 1 | p[0][0] = 1.0; | |
| 82 | 1 | p[0][1] = 0.0; | |
| 83 |
2/2✓ Branch 0 taken 4 times.
✓ Branch 1 taken 1 times.
|
5 | for (i = 1; i <= order; i++) |
| 84 | 4 | p[i][0] = p[i][1] = 0.0; | |
| 85 |
2/2✓ Branch 0 taken 4 times.
✓ Branch 1 taken 1 times.
|
5 | for (i = 0; i < order; i++) { |
| 86 | double zp[2]; | ||
| 87 | 4 | double th = (i + (order >> 1) + 0.5) * M_PI / order; | |
| 88 | double a_re, a_im, c_re, c_im; | ||
| 89 | 4 | zp[0] = cos(th) * wa; | |
| 90 | 4 | zp[1] = sin(th) * wa; | |
| 91 | 4 | a_re = zp[0] + 2.0; | |
| 92 | 4 | c_re = zp[0] - 2.0; | |
| 93 | 4 | a_im = | |
| 94 | 4 | c_im = zp[1]; | |
| 95 | 4 | zp[0] = (a_re * c_re + a_im * c_im) / (c_re * c_re + c_im * c_im); | |
| 96 | 4 | zp[1] = (a_im * c_re - a_re * c_im) / (c_re * c_re + c_im * c_im); | |
| 97 | |||
| 98 |
2/2✓ Branch 0 taken 16 times.
✓ Branch 1 taken 4 times.
|
20 | for (j = order; j >= 1; j--) { |
| 99 | 16 | a_re = p[j][0]; | |
| 100 | 16 | a_im = p[j][1]; | |
| 101 | 16 | p[j][0] = a_re * zp[0] - a_im * zp[1] + p[j - 1][0]; | |
| 102 | 16 | p[j][1] = a_re * zp[1] + a_im * zp[0] + p[j - 1][1]; | |
| 103 | } | ||
| 104 | 4 | a_re = p[0][0] * zp[0] - p[0][1] * zp[1]; | |
| 105 | 4 | p[0][1] = p[0][0] * zp[1] + p[0][1] * zp[0]; | |
| 106 | 4 | p[0][0] = a_re; | |
| 107 | } | ||
| 108 | 1 | c->gain = p[order][0]; | |
| 109 |
2/2✓ Branch 0 taken 4 times.
✓ Branch 1 taken 1 times.
|
5 | for (i = 0; i < order; i++) { |
| 110 | 4 | c->gain += p[i][0]; | |
| 111 | 4 | c->cy[i] = (-p[i][0] * p[order][0] + -p[i][1] * p[order][1]) / | |
| 112 | 4 | (p[order][0] * p[order][0] + p[order][1] * p[order][1]); | |
| 113 | } | ||
| 114 | 1 | c->gain /= 1 << order; | |
| 115 | |||
| 116 | 1 | return 0; | |
| 117 | } | ||
| 118 | |||
| 119 | ✗ | static av_cold int biquad_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c, | |
| 120 | enum IIRFilterMode filt_mode, int order, | ||
| 121 | float cutoff_ratio, float stopband) | ||
| 122 | { | ||
| 123 | double cos_w0, sin_w0; | ||
| 124 | double a0, x0, x1; | ||
| 125 | |||
| 126 | ✗ | if (filt_mode != FF_FILTER_MODE_HIGHPASS && | |
| 127 | filt_mode != FF_FILTER_MODE_LOWPASS) { | ||
| 128 | ✗ | av_log(avc, AV_LOG_ERROR, "Biquad filter currently only supports " | |
| 129 | "high-pass and low-pass filter modes\n"); | ||
| 130 | ✗ | return -1; | |
| 131 | } | ||
| 132 | ✗ | if (order != 2) { | |
| 133 | ✗ | av_log(avc, AV_LOG_ERROR, "Biquad filter must have order of 2\n"); | |
| 134 | ✗ | return -1; | |
| 135 | } | ||
| 136 | |||
| 137 | ✗ | cos_w0 = cos(M_PI * cutoff_ratio); | |
| 138 | ✗ | sin_w0 = sin(M_PI * cutoff_ratio); | |
| 139 | |||
| 140 | ✗ | a0 = 1.0 + (sin_w0 / 2.0); | |
| 141 | |||
| 142 | ✗ | if (filt_mode == FF_FILTER_MODE_HIGHPASS) { | |
| 143 | ✗ | c->gain = ((1.0 + cos_w0) / 2.0) / a0; | |
| 144 | ✗ | x0 = ((1.0 + cos_w0) / 2.0) / a0; | |
| 145 | ✗ | x1 = (-(1.0 + cos_w0)) / a0; | |
| 146 | } else { // FF_FILTER_MODE_LOWPASS | ||
| 147 | ✗ | c->gain = ((1.0 - cos_w0) / 2.0) / a0; | |
| 148 | ✗ | x0 = ((1.0 - cos_w0) / 2.0) / a0; | |
| 149 | ✗ | x1 = (1.0 - cos_w0) / a0; | |
| 150 | } | ||
| 151 | ✗ | c->cy[0] = (-1.0 + (sin_w0 / 2.0)) / a0; | |
| 152 | ✗ | c->cy[1] = (2.0 * cos_w0) / a0; | |
| 153 | |||
| 154 | // divide by gain to make the x coeffs integers. | ||
| 155 | // during filtering, the delay state will include the gain multiplication | ||
| 156 | ✗ | c->cx[0] = lrintf(x0 / c->gain); | |
| 157 | ✗ | c->cx[1] = lrintf(x1 / c->gain); | |
| 158 | |||
| 159 | ✗ | return 0; | |
| 160 | } | ||
| 161 | |||
| 162 | 1 | av_cold struct FFIIRFilterCoeffs *ff_iir_filter_init_coeffs(void *avc, | |
| 163 | enum IIRFilterType filt_type, | ||
| 164 | enum IIRFilterMode filt_mode, | ||
| 165 | int order, float cutoff_ratio, | ||
| 166 | float stopband, float ripple) | ||
| 167 | { | ||
| 168 | FFIIRFilterCoeffs *c; | ||
| 169 | 1 | int ret = 0; | |
| 170 | |||
| 171 |
3/6✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
✓ Branch 2 taken 1 times.
✗ Branch 3 not taken.
✗ Branch 4 not taken.
✓ Branch 5 taken 1 times.
|
1 | if (order <= 0 || order > MAXORDER || cutoff_ratio >= 1.0) |
| 172 | ✗ | return NULL; | |
| 173 | |||
| 174 |
1/2✓ Branch 1 taken 1 times.
✗ Branch 2 not taken.
|
1 | if (!(c = av_mallocz(sizeof(*c))) || |
| 175 |
1/2✓ Branch 1 taken 1 times.
✗ Branch 2 not taken.
|
1 | !(c->cx = av_malloc (sizeof(c->cx[0]) * ((order >> 1) + 1))) || |
| 176 |
1/2✗ Branch 1 not taken.
✓ Branch 2 taken 1 times.
|
1 | !(c->cy = av_malloc (sizeof(c->cy[0]) * order))) |
| 177 | ✗ | goto free; | |
| 178 | 1 | c->order = order; | |
| 179 | |||
| 180 |
1/3✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
|
1 | switch (filt_type) { |
| 181 | 1 | case FF_FILTER_TYPE_BUTTERWORTH: | |
| 182 | 1 | ret = butterworth_init_coeffs(avc, c, filt_mode, order, cutoff_ratio, | |
| 183 | stopband); | ||
| 184 | 1 | break; | |
| 185 | ✗ | case FF_FILTER_TYPE_BIQUAD: | |
| 186 | ✗ | ret = biquad_init_coeffs(avc, c, filt_mode, order, cutoff_ratio, | |
| 187 | stopband); | ||
| 188 | ✗ | break; | |
| 189 | ✗ | default: | |
| 190 | ✗ | av_log(avc, AV_LOG_ERROR, "filter type is not currently implemented\n"); | |
| 191 | ✗ | goto free; | |
| 192 | } | ||
| 193 | |||
| 194 |
1/2✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
|
1 | if (!ret) |
| 195 | 1 | return c; | |
| 196 | ✗ | free: | |
| 197 | ✗ | ff_iir_filter_free_coeffsp(&c); | |
| 198 | ✗ | return NULL; | |
| 199 | } | ||
| 200 | |||
| 201 | 1 | av_cold struct FFIIRFilterState *ff_iir_filter_init_state(int order) | |
| 202 | { | ||
| 203 | 1 | FFIIRFilterState *s = av_mallocz(sizeof(FFIIRFilterState) + sizeof(s->x[0]) * (order - 1)); | |
| 204 | 1 | return s; | |
| 205 | } | ||
| 206 | |||
| 207 | #define CONV_S16(dest, source) dest = av_clip_int16(lrintf(source)); | ||
| 208 | |||
| 209 | #define CONV_FLT(dest, source) dest = source; | ||
| 210 | |||
| 211 | #define FILTER_BW_O4_1(i0, i1, i2, i3, fmt) \ | ||
| 212 | in = *src0 * c->gain + \ | ||
| 213 | c->cy[0] * s->x[i0] + \ | ||
| 214 | c->cy[1] * s->x[i1] + \ | ||
| 215 | c->cy[2] * s->x[i2] + \ | ||
| 216 | c->cy[3] * s->x[i3]; \ | ||
| 217 | res = (s->x[i0] + in) * 1 + \ | ||
| 218 | (s->x[i1] + s->x[i3]) * 4 + \ | ||
| 219 | s->x[i2] * 6; \ | ||
| 220 | CONV_ ## fmt(*dst0, res) \ | ||
| 221 | s->x[i0] = in; \ | ||
| 222 | src0 += sstep; \ | ||
| 223 | dst0 += dstep; | ||
| 224 | |||
| 225 | #define FILTER_BW_O4(type, fmt) { \ | ||
| 226 | int i; \ | ||
| 227 | const type *src0 = src; \ | ||
| 228 | type *dst0 = dst; \ | ||
| 229 | for (i = 0; i < size; i += 4) { \ | ||
| 230 | float in, res; \ | ||
| 231 | FILTER_BW_O4_1(0, 1, 2, 3, fmt); \ | ||
| 232 | FILTER_BW_O4_1(1, 2, 3, 0, fmt); \ | ||
| 233 | FILTER_BW_O4_1(2, 3, 0, 1, fmt); \ | ||
| 234 | FILTER_BW_O4_1(3, 0, 1, 2, fmt); \ | ||
| 235 | } \ | ||
| 236 | } | ||
| 237 | |||
| 238 | #define FILTER_DIRECT_FORM_II(type, fmt) { \ | ||
| 239 | int i; \ | ||
| 240 | const type *src0 = src; \ | ||
| 241 | type *dst0 = dst; \ | ||
| 242 | for (i = 0; i < size; i++) { \ | ||
| 243 | int j; \ | ||
| 244 | float in, res; \ | ||
| 245 | in = *src0 * c->gain; \ | ||
| 246 | for (j = 0; j < c->order; j++) \ | ||
| 247 | in += c->cy[j] * s->x[j]; \ | ||
| 248 | res = s->x[0] + in + s->x[c->order >> 1] * c->cx[c->order >> 1]; \ | ||
| 249 | for (j = 1; j < c->order >> 1; j++) \ | ||
| 250 | res += (s->x[j] + s->x[c->order - j]) * c->cx[j]; \ | ||
| 251 | for (j = 0; j < c->order - 1; j++) \ | ||
| 252 | s->x[j] = s->x[j + 1]; \ | ||
| 253 | CONV_ ## fmt(*dst0, res) \ | ||
| 254 | s->x[c->order - 1] = in; \ | ||
| 255 | src0 += sstep; \ | ||
| 256 | dst0 += dstep; \ | ||
| 257 | } \ | ||
| 258 | } | ||
| 259 | |||
| 260 | #define FILTER_O2(type, fmt) { \ | ||
| 261 | int i; \ | ||
| 262 | const type *src0 = src; \ | ||
| 263 | type *dst0 = dst; \ | ||
| 264 | for (i = 0; i < size; i++) { \ | ||
| 265 | float in = *src0 * c->gain + \ | ||
| 266 | s->x[0] * c->cy[0] + \ | ||
| 267 | s->x[1] * c->cy[1]; \ | ||
| 268 | CONV_ ## fmt(*dst0, s->x[0] + in + s->x[1] * c->cx[1]) \ | ||
| 269 | s->x[0] = s->x[1]; \ | ||
| 270 | s->x[1] = in; \ | ||
| 271 | src0 += sstep; \ | ||
| 272 | dst0 += dstep; \ | ||
| 273 | } \ | ||
| 274 | } | ||
| 275 | |||
| 276 | 1 | void ff_iir_filter(const struct FFIIRFilterCoeffs *c, | |
| 277 | struct FFIIRFilterState *s, int size, | ||
| 278 | const int16_t *src, ptrdiff_t sstep, | ||
| 279 | int16_t *dst, ptrdiff_t dstep) | ||
| 280 | { | ||
| 281 |
1/2✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
|
1 | if (c->order == 2) { |
| 282 | ✗ | FILTER_O2(int16_t, S16) | |
| 283 |
1/2✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
|
1 | } else if (c->order == 4) { |
| 284 |
2/2✓ Branch 0 taken 256 times.
✓ Branch 1 taken 1 times.
|
257 | FILTER_BW_O4(int16_t, S16) |
| 285 | } else { | ||
| 286 | ✗ | FILTER_DIRECT_FORM_II(int16_t, S16) | |
| 287 | } | ||
| 288 | 1 | } | |
| 289 | |||
| 290 | /** | ||
| 291 | * Perform IIR filtering on floating-point input samples. | ||
| 292 | * | ||
| 293 | * @param coeffs pointer to filter coefficients | ||
| 294 | * @param state pointer to filter state | ||
| 295 | * @param size input length | ||
| 296 | * @param src source samples | ||
| 297 | * @param sstep source stride | ||
| 298 | * @param dst filtered samples (destination may be the same as input) | ||
| 299 | * @param dstep destination stride | ||
| 300 | */ | ||
| 301 | ✗ | static void iir_filter_flt(const struct FFIIRFilterCoeffs *c, | |
| 302 | struct FFIIRFilterState *s, int size, | ||
| 303 | const float *src, ptrdiff_t sstep, | ||
| 304 | float *dst, ptrdiff_t dstep) | ||
| 305 | { | ||
| 306 | ✗ | if (c->order == 2) { | |
| 307 | ✗ | FILTER_O2(float, FLT) | |
| 308 | ✗ | } else if (c->order == 4) { | |
| 309 | ✗ | FILTER_BW_O4(float, FLT) | |
| 310 | } else { | ||
| 311 | ✗ | FILTER_DIRECT_FORM_II(float, FLT) | |
| 312 | } | ||
| 313 | } | ||
| 314 | |||
| 315 | 1 | av_cold void ff_iir_filter_free_statep(struct FFIIRFilterState **state) | |
| 316 | { | ||
| 317 | 1 | av_freep(state); | |
| 318 | 1 | } | |
| 319 | |||
| 320 | 12 | av_cold void ff_iir_filter_free_coeffsp(struct FFIIRFilterCoeffs **coeffsp) | |
| 321 | { | ||
| 322 | 12 | struct FFIIRFilterCoeffs *coeffs = *coeffsp; | |
| 323 |
2/2✓ Branch 0 taken 1 times.
✓ Branch 1 taken 11 times.
|
12 | if (coeffs) { |
| 324 | 1 | av_freep(&coeffs->cx); | |
| 325 | 1 | av_freep(&coeffs->cy); | |
| 326 | } | ||
| 327 | 12 | av_freep(coeffsp); | |
| 328 | 12 | } | |
| 329 | |||
| 330 | 11 | void ff_iir_filter_init(FFIIRFilterContext *f) { | |
| 331 | 11 | f->filter_flt = iir_filter_flt; | |
| 332 | |||
| 333 | #if HAVE_MIPSFPU | ||
| 334 | ff_iir_filter_init_mips(f); | ||
| 335 | #endif | ||
| 336 | 11 | } | |
| 337 |