FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavfilter/af_asupercut.c
Date: 2026-09-24 20:08:24
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1 /*
2 * Copyright (c) 2005 Boðaç Topaktaþ
3 * Copyright (c) 2020 Paul B Mahol
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 #include "libavutil/channel_layout.h"
23 #include "libavutil/ffmath.h"
24 #include "libavutil/opt.h"
25 #include "avfilter.h"
26 #include "audio.h"
27 #include "filters.h"
28
29 typedef struct BiquadCoeffs {
30 double a1, a2;
31 double b0, b1, b2;
32 } BiquadCoeffs;
33
34 typedef struct ASuperCutContext {
35 const AVClass *class;
36
37 double cutoff;
38 double level;
39 double qfactor;
40 int order;
41
42 int filter_count;
43 int bypass;
44
45 BiquadCoeffs coeffs[10];
46
47 AVFrame *w;
48
49 int (*filter_channels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
50 } ASuperCutContext;
51
52 static const enum AVSampleFormat sample_fmts[] = {
53 AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE
54 };
55
56 ✗ static void calc_q_factors(int n, double *q)
57 {
58 ✗ for (int i = 0; i < n / 2; i++)
59 ✗ q[i] = 1. / (-2. * cos(M_PI * (2. * (i + 1) + n - 1.) / (2. * n)));
60 ✗ }
61
62 ✗ static int get_coeffs(AVFilterContext *ctx)
63 {
64 ✗ ASuperCutContext *s = ctx->priv;
65 ✗ AVFilterLink *inlink = ctx->inputs[0];
66 ✗ double w0 = s->cutoff / inlink->sample_rate;
67 ✗ double K = tan(M_PI * w0);
68 double q[10];
69
70 ✗ s->bypass = w0 >= 0.5;
71 ✗ if (s->bypass)
72 ✗ return 0;
73
74 ✗ if (!strcmp(ctx->filter->name, "asubcut")) {
75 ✗ s->filter_count = s->order / 2 + (s->order & 1);
76
77 ✗ calc_q_factors(s->order, q);
78
79 ✗ if (s->order & 1) {
80 ✗ BiquadCoeffs *coeffs = &s->coeffs[0];
81 ✗ double omega = 2. * tan(M_PI * w0);
82
83 ✗ coeffs->b0 = 2. / (2. + omega);
84 ✗ coeffs->b1 = -coeffs->b0;
85 ✗ coeffs->b2 = 0.;
86 ✗ coeffs->a1 = -(omega - 2.) / (2. + omega);
87 ✗ coeffs->a2 = 0.;
88 }
89
90 ✗ for (int b = (s->order & 1); b < s->filter_count; b++) {
91 ✗ BiquadCoeffs *coeffs = &s->coeffs[b];
92 ✗ const int idx = b - (s->order & 1);
93 ✗ double norm = 1.0 / (1.0 + K / q[idx] + K * K);
94
95 ✗ coeffs->b0 = norm;
96 ✗ coeffs->b1 = -2.0 * coeffs->b0;
97 ✗ coeffs->b2 = coeffs->b0;
98 ✗ coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
99 ✗ coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
100 }
101 ✗ } else if (!strcmp(ctx->filter->name, "asupercut")) {
102 ✗ s->filter_count = s->order / 2 + (s->order & 1);
103
104 ✗ calc_q_factors(s->order, q);
105
106 ✗ if (s->order & 1) {
107 ✗ BiquadCoeffs *coeffs = &s->coeffs[0];
108 ✗ double omega = 2. * tan(M_PI * w0);
109
110 ✗ coeffs->b0 = omega / (2. + omega);
111 ✗ coeffs->b1 = coeffs->b0;
112 ✗ coeffs->b2 = 0.;
113 ✗ coeffs->a1 = -(omega - 2.) / (2. + omega);
114 ✗ coeffs->a2 = 0.;
115 }
116
117 ✗ for (int b = (s->order & 1); b < s->filter_count; b++) {
118 ✗ BiquadCoeffs *coeffs = &s->coeffs[b];
119 ✗ const int idx = b - (s->order & 1);
120 ✗ double norm = 1.0 / (1.0 + K / q[idx] + K * K);
121
122 ✗ coeffs->b0 = K * K * norm;
123 ✗ coeffs->b1 = 2.0 * coeffs->b0;
124 ✗ coeffs->b2 = coeffs->b0;
125 ✗ coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
126 ✗ coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
127 }
128 ✗ } else if (!strcmp(ctx->filter->name, "asuperpass")) {
129 double alpha, beta, gamma, theta;
130 ✗ double theta_0 = 2. * M_PI * (s->cutoff / inlink->sample_rate);
131 double d_E;
132
133 ✗ s->filter_count = s->order / 2;
134 ✗ d_E = (2. * tan(theta_0 / (2. * s->qfactor))) / sin(theta_0);
135
136 ✗ for (int b = 0; b < s->filter_count; b += 2) {
137 ✗ double D = 2. * sin(((b + 1) * M_PI) / (2. * s->filter_count));
138 ✗ double A = (1. + pow((d_E / 2.), 2)) / (D * d_E / 2.);
139 ✗ double d = sqrt((d_E * D) / (A + sqrt(A * A - 1.)));
140 ✗ double B = D * (d_E / 2.) / d;
141 ✗ double W = B + sqrt(B * B - 1.);
142
143 ✗ for (int j = 0; j < 2; j++) {
144 ✗ BiquadCoeffs *coeffs = &s->coeffs[b + j];
145
146 ✗ if (j == 1)
147 ✗ theta = 2. * atan(tan(theta_0 / 2.) / W);
148 else
149 ✗ theta = 2. * atan(W * tan(theta_0 / 2.));
150
151 ✗ beta = 0.5 * ((1. - (d / 2.) * sin(theta)) / (1. + (d / 2.) * sin(theta)));
152 ✗ gamma = (0.5 + beta) * cos(theta);
153 ✗ alpha = 0.5 * (0.5 - beta) * sqrt(1. + pow((W - (1. / W)) / d, 2.));
154
155 ✗ coeffs->a1 = 2. * gamma;
156 ✗ coeffs->a2 = -2. * beta;
157 ✗ coeffs->b0 = 2. * alpha;
158 ✗ coeffs->b1 = 0.;
159 ✗ coeffs->b2 = -2. * alpha;
160 }
161 }
162 ✗ } else if (!strcmp(ctx->filter->name, "asuperstop")) {
163 double alpha, beta, gamma, theta;
164 ✗ double theta_0 = 2. * M_PI * (s->cutoff / inlink->sample_rate);
165 double d_E;
166
167 ✗ s->filter_count = s->order / 2;
168 ✗ d_E = (2. * tan(theta_0 / (2. * s->qfactor))) / sin(theta_0);
169
170 ✗ for (int b = 0; b < s->filter_count; b += 2) {
171 ✗ double D = 2. * sin(((b + 1) * M_PI) / (2. * s->filter_count));
172 ✗ double A = (1. + pow((d_E / 2.), 2)) / (D * d_E / 2.);
173 ✗ double d = sqrt((d_E * D) / (A + sqrt(A * A - 1.)));
174 ✗ double B = D * (d_E / 2.) / d;
175 ✗ double W = B + sqrt(B * B - 1.);
176
177 ✗ for (int j = 0; j < 2; j++) {
178 ✗ BiquadCoeffs *coeffs = &s->coeffs[b + j];
179
180 ✗ if (j == 1)
181 ✗ theta = 2. * atan(tan(theta_0 / 2.) / W);
182 else
183 ✗ theta = 2. * atan(W * tan(theta_0 / 2.));
184
185 ✗ beta = 0.5 * ((1. - (d / 2.) * sin(theta)) / (1. + (d / 2.) * sin(theta)));
186 ✗ gamma = (0.5 + beta) * cos(theta);
187 ✗ alpha = 0.5 * (0.5 + beta) * ((1. - cos(theta)) / (1. - cos(theta_0)));
188
189 ✗ coeffs->a1 = 2. * gamma;
190 ✗ coeffs->a2 = -2. * beta;
191 ✗ coeffs->b0 = 2. * alpha;
192 ✗ coeffs->b1 = -4. * alpha * cos(theta_0);
193 ✗ coeffs->b2 = 2. * alpha;
194 }
195 }
196 }
197
198 ✗ return 0;
199 }
200
201 typedef struct ThreadData {
202 AVFrame *in, *out;
203 } ThreadData;
204
205 #define FILTER(name, type) \
206 static int filter_channels_## name(AVFilterContext *ctx, void *arg, \
207 int jobnr, int nb_jobs) \
208 { \
209 ASuperCutContext *s = ctx->priv; \
210 ThreadData *td = arg; \
211 AVFrame *out = td->out; \
212 AVFrame *in = td->in; \
213 const int start = ff_slice_pos(in->ch_layout.nb_channels, jobnr, nb_jobs); \
214 const int end = ff_slice_pos(in->ch_layout.nb_channels, jobnr + 1, nb_jobs); \
215 const double level = s->level; \
216 \
217 for (int ch = start; ch < end; ch++) { \
218 const type *src = (const type *)in->extended_data[ch]; \
219 type *dst = (type *)out->extended_data[ch]; \
220 \
221 for (int b = 0; b < s->filter_count; b++) { \
222 BiquadCoeffs *coeffs = &s->coeffs[b]; \
223 const type a1 = coeffs->a1; \
224 const type a2 = coeffs->a2; \
225 const type b0 = coeffs->b0; \
226 const type b1 = coeffs->b1; \
227 const type b2 = coeffs->b2; \
228 type *w = ((type *)s->w->extended_data[ch]) + b * 2; \
229 \
230 for (int n = 0; n < in->nb_samples; n++) { \
231 type sin = b ? dst[n] : src[n] * level; \
232 type sout = sin * b0 + w[0]; \
233 \
234 w[0] = b1 * sin + w[1] + a1 * sout; \
235 w[1] = b2 * sin + a2 * sout; \
236 \
237 dst[n] = sout; \
238 } \
239 } \
240 } \
241 \
242 return 0; \
243 }
244
245 ✗ FILTER(fltp, float)
246 ✗ FILTER(dblp, double)
247
248 ✗ static int config_input(AVFilterLink *inlink)
249 {
250 ✗ AVFilterContext *ctx = inlink->dst;
251 ✗ ASuperCutContext *s = ctx->priv;
252
253 ✗ switch (inlink->format) {
254 ✗ case AV_SAMPLE_FMT_FLTP: s->filter_channels = filter_channels_fltp; break;
255 ✗ case AV_SAMPLE_FMT_DBLP: s->filter_channels = filter_channels_dblp; break;
256 }
257
258 ✗ s->w = ff_get_audio_buffer(inlink, 2 * 10);
259 ✗ if (!s->w)
260 ✗ return AVERROR(ENOMEM);
261
262 ✗ return get_coeffs(ctx);
263 }
264
265 ✗ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
266 {
267 ✗ AVFilterContext *ctx = inlink->dst;
268 ✗ ASuperCutContext *s = ctx->priv;
269 ✗ AVFilterLink *outlink = ctx->outputs[0];
270 ThreadData td;
271 AVFrame *out;
272
273 ✗ if (s->bypass)
274 ✗ return ff_filter_frame(outlink, in);
275
276 ✗ if (av_frame_is_writable(in)) {
277 ✗ out = in;
278 } else {
279 ✗ out = ff_get_audio_buffer(outlink, in->nb_samples);
280 ✗ if (!out) {
281 ✗ av_frame_free(&in);
282 ✗ return AVERROR(ENOMEM);
283 }
284 ✗ av_frame_copy_props(out, in);
285 }
286
287 ✗ td.in = in; td.out = out;
288 ✗ ff_filter_execute(ctx, s->filter_channels, &td, NULL,
289 ✗ FFMIN(inlink->ch_layout.nb_channels, ff_filter_get_nb_threads(ctx)));
290
291 ✗ if (out != in)
292 ✗ av_frame_free(&in);
293 ✗ return ff_filter_frame(outlink, out);
294 }
295
296 ✗ static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
297 char *res, int res_len, int flags)
298 {
299 int ret;
300
301 ✗ ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
302 ✗ if (ret < 0)
303 ✗ return ret;
304
305 ✗ return get_coeffs(ctx);
306 }
307
308 ✗ static av_cold void uninit(AVFilterContext *ctx)
309 {
310 ✗ ASuperCutContext *s = ctx->priv;
311
312 ✗ av_frame_free(&s->w);
313 ✗ }
314
315 #define OFFSET(x) offsetof(ASuperCutContext, x)
316 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
317
318 static const AVOption asupercut_options[] = {
319 { "cutoff", "set cutoff frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=20000}, 20000, 192000, FLAGS },
320 { "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=10}, 3, 20, FLAGS },
321 { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 1., FLAGS },
322 { NULL }
323 };
324
325 AVFILTER_DEFINE_CLASS(asupercut);
326
327 static const AVFilterPad inputs[] = {
328 {
329 .name = "default",
330 .type = AVMEDIA_TYPE_AUDIO,
331 .filter_frame = filter_frame,
332 .config_props = config_input,
333 },
334 };
335
336 const FFFilter ff_af_asupercut = {
337 .p.name = "asupercut",
338 .p.description = NULL_IF_CONFIG_SMALL("Cut super frequencies."),
339 .p.priv_class = &asupercut_class,
340 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
341 AVFILTER_FLAG_SLICE_THREADS,
342 .priv_size = sizeof(ASuperCutContext),
343 .uninit = uninit,
344 FILTER_INPUTS(inputs),
345 FILTER_OUTPUTS(ff_audio_default_filterpad),
346 FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
347 .process_command = process_command,
348 };
349
350 static const AVOption asubcut_options[] = {
351 { "cutoff", "set cutoff frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 2, 200, FLAGS },
352 { "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=10}, 3, 20, FLAGS },
353 { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 1., FLAGS },
354 { NULL }
355 };
356
357 AVFILTER_DEFINE_CLASS(asubcut);
358
359 const FFFilter ff_af_asubcut = {
360 .p.name = "asubcut",
361 .p.description = NULL_IF_CONFIG_SMALL("Cut subwoofer frequencies."),
362 .p.priv_class = &asubcut_class,
363 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
364 AVFILTER_FLAG_SLICE_THREADS,
365 .priv_size = sizeof(ASuperCutContext),
366 .uninit = uninit,
367 FILTER_INPUTS(inputs),
368 FILTER_OUTPUTS(ff_audio_default_filterpad),
369 FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
370 .process_command = process_command,
371 };
372
373 static const AVOption asuperpass_asuperstop_options[] = {
374 { "centerf","set center frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=1000}, 2, 999999, FLAGS },
375 { "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=4}, 4, 20, FLAGS },
376 { "qfactor","set Q-factor", OFFSET(qfactor),AV_OPT_TYPE_DOUBLE, {.dbl=1.},0.01, 100., FLAGS },
377 { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 2., FLAGS },
378 { NULL }
379 };
380
381 AVFILTER_DEFINE_CLASS_EXT(asuperpass_asuperstop, "asuperpass/asuperstop",
382 asuperpass_asuperstop_options);
383
384 const FFFilter ff_af_asuperpass = {
385 .p.name = "asuperpass",
386 .p.description = NULL_IF_CONFIG_SMALL("Apply high order Butterworth band-pass filter."),
387 .p.priv_class = &asuperpass_asuperstop_class,
388 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
389 AVFILTER_FLAG_SLICE_THREADS,
390 .priv_size = sizeof(ASuperCutContext),
391 .uninit = uninit,
392 FILTER_INPUTS(inputs),
393 FILTER_OUTPUTS(ff_audio_default_filterpad),
394 FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
395 .process_command = process_command,
396 };
397
398 const FFFilter ff_af_asuperstop = {
399 .p.name = "asuperstop",
400 .p.description = NULL_IF_CONFIG_SMALL("Apply high order Butterworth band-stop filter."),
401 .p.priv_class = &asuperpass_asuperstop_class,
402 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
403 AVFILTER_FLAG_SLICE_THREADS,
404 .priv_size = sizeof(ASuperCutContext),
405 .uninit = uninit,
406 FILTER_INPUTS(inputs),
407 FILTER_OUTPUTS(ff_audio_default_filterpad),
408 FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
409 .process_command = process_command,
410 };
411