2 * Copyright (c) 2013 Paul B Mahol
3 * Copyright (c) 2006-2008 Rob Sykes <robs@users.sourceforge.net>
5 * This file is part of FFmpeg.
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.
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.
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
23 * 2-pole filters designed by Robert Bristow-Johnson <rbj@audioimagination.com>
24 * see http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
26 * 1-pole filters based on code (c) 2000 Chris Bagwell <cbagwell@sprynet.com>
27 * Algorithms: Recursive single pole low/high pass filter
28 * Reference: The Scientist and Engineer's Guide to Digital Signal Processing
30 * low-pass: output[N] = input[N] * A + output[N-1] * B
31 * X = exp(-2.0 * pi * Fc)
34 * Fc = cutoff freq / sample rate
36 * Mimics an RC low-pass filter:
38 * ---/\/\/\/\----------->
46 * high-pass: output[N] = A0 * input[N] + A1 * input[N-1] + B1 * output[N-1]
47 * X = exp(-2.0 * pi * Fc)
51 * Fc = cutoff freq / sample rate
53 * Mimics an RC high-pass filter:
65 #include "libavutil/opt.h"
66 #include "libavutil/avassert.h"
92 typedef struct ChanCache {
100 enum FilterType filter_type;
101 enum WidthType width_type;
114 void (*filter)(const void *ibuf, void *obuf, int len,
115 double *i1, double *i2, double *o1, double *o2,
116 double b0, double b1, double b2, double a1, double a2);
119 static av_cold int init(AVFilterContext *ctx, const char *args)
121 BiquadsContext *p = ctx->priv;
124 av_opt_set_defaults(p);
126 if ((ret = av_set_options_string(p, args, "=", ":")) < 0)
129 if (p->filter_type != biquad) {
130 if (p->frequency <= 0 || p->width <= 0) {
131 av_log(ctx, AV_LOG_ERROR, "Invalid frequency %f and/or width %f <= 0\n",
132 p->frequency, p->width);
133 return AVERROR(EINVAL);
140 static int query_formats(AVFilterContext *ctx)
142 AVFilterFormats *formats;
143 AVFilterChannelLayouts *layouts;
144 static const enum AVSampleFormat sample_fmts[] = {
152 layouts = ff_all_channel_layouts();
154 return AVERROR(ENOMEM);
155 ff_set_common_channel_layouts(ctx, layouts);
157 formats = ff_make_format_list(sample_fmts);
159 return AVERROR(ENOMEM);
160 ff_set_common_formats(ctx, formats);
162 formats = ff_all_samplerates();
164 return AVERROR(ENOMEM);
165 ff_set_common_samplerates(ctx, formats);
170 #define BIQUAD_FILTER(name, type, min, max) \
171 static void biquad_## name (const void *input, void *output, int len, \
172 double *in1, double *in2, \
173 double *out1, double *out2, \
174 double b0, double b1, double b2, \
175 double a1, double a2) \
177 const type *ibuf = input; \
178 type *obuf = output; \
185 for (i = 0; i < len; i++) { \
186 double o0 = ibuf[i] * b0 + i1 * b1 + i2 * b2 - o1 * a1 - o2 * a2; \
192 av_log(NULL, AV_LOG_WARNING, "clipping\n"); \
194 } else if (o0 > max) { \
195 av_log(NULL, AV_LOG_WARNING, "clipping\n"); \
207 BIQUAD_FILTER(s16, int16_t, INT16_MIN, INT16_MAX)
208 BIQUAD_FILTER(s32, int32_t, INT32_MIN, INT32_MAX)
209 BIQUAD_FILTER(flt, float, -1., 1.)
210 BIQUAD_FILTER(dbl, double, -1., 1.)
212 static int config_output(AVFilterLink *outlink)
214 AVFilterContext *ctx = outlink->src;
215 BiquadsContext *p = ctx->priv;
216 AVFilterLink *inlink = ctx->inputs[0];
217 double A = exp(p->gain / 40 * log(10.));
218 double w0 = 2 * M_PI * p->frequency / inlink->sample_rate;
222 av_log(ctx, AV_LOG_ERROR,
223 "Invalid frequency %f. Frequency must be less than half the sample-rate %d.\n",
224 p->frequency, inlink->sample_rate);
225 return AVERROR(EINVAL);
228 switch (p->width_type) {
233 alpha = sin(w0) / (2 * p->frequency / p->width);
236 alpha = sin(w0) * sinh(log(2.) / 2 * p->width * w0 / sin(w0));
239 alpha = sin(w0) / (2 * p->width);
242 alpha = sin(w0) / 2 * sqrt((A + 1 / A) * (1 / p->width - 1) + 2);
248 switch (p->filter_type) {
252 p->a0 = 1 + alpha / A;
253 p->a1 = -2 * cos(w0);
254 p->a2 = 1 - alpha / A;
255 p->b0 = 1 + alpha * A;
256 p->b1 = -2 * cos(w0);
257 p->b2 = 1 - alpha * A;
260 p->a0 = (A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha;
261 p->a1 = -2 * ((A - 1) + (A + 1) * cos(w0));
262 p->a2 = (A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha;
263 p->b0 = A * ((A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha);
264 p->b1 = 2 * A * ((A - 1) - (A + 1) * cos(w0));
265 p->b2 = A * ((A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha);
268 p->a0 = (A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha;
269 p->a1 = 2 * ((A - 1) - (A + 1) * cos(w0));
270 p->a2 = (A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha;
271 p->b0 = A * ((A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha);
272 p->b1 =-2 * A * ((A - 1) + (A + 1) * cos(w0));
273 p->b2 = A * ((A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha);
278 p->a1 = -2 * cos(w0);
282 p->b2 = -sin(w0) / 2;
285 p->a1 = -2 * cos(w0);
294 p->a1 = -2 * cos(w0);
297 p->b1 = -2 * cos(w0);
310 p->a1 = -2 * cos(w0);
312 p->b0 = (1 - cos(w0)) / 2;
314 p->b2 = (1 - cos(w0)) / 2;
322 p->b0 = (1 - p->a1) / 2;
327 p->a1 = -2 * cos(w0);
329 p->b0 = (1 + cos(w0)) / 2;
330 p->b1 = -(1 + cos(w0));
331 p->b2 = (1 + cos(w0)) / 2;
336 p->a1 = -2 * cos(w0);
339 p->b1 = -2 * cos(w0);
352 p->cache = av_realloc_f(p->cache, sizeof(ChanCache), inlink->channels);
354 return AVERROR(ENOMEM);
356 switch (inlink->format) {
357 case AV_SAMPLE_FMT_S16P: p->filter = biquad_s16; break;
358 case AV_SAMPLE_FMT_S32P: p->filter = biquad_s32; break;
359 case AV_SAMPLE_FMT_FLTP: p->filter = biquad_flt; break;
360 case AV_SAMPLE_FMT_DBLP: p->filter = biquad_dbl; break;
361 default: av_assert0(0);
367 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
369 BiquadsContext *p = inlink->dst->priv;
370 AVFilterLink *outlink = inlink->dst->outputs[0];
371 AVFilterBufferRef *out_buf;
372 int nb_samples = buf->audio->nb_samples;
375 if (buf->perms & AV_PERM_WRITE) {
378 out_buf = ff_get_audio_buffer(inlink, AV_PERM_WRITE, nb_samples);
380 return AVERROR(ENOMEM);
381 out_buf->pts = buf->pts;
384 for (ch = 0; ch < buf->audio->channels; ch++)
385 p->filter(buf->extended_data[ch],
386 out_buf->extended_data[ch], nb_samples,
387 &p->cache[ch].i1, &p->cache[ch].i2,
388 &p->cache[ch].o1, &p->cache[ch].o2,
389 p->b0, p->b1, p->b2, p->a1, p->a2);
392 avfilter_unref_buffer(buf);
394 return ff_filter_frame(outlink, out_buf);
397 static av_cold void uninit(AVFilterContext *ctx)
399 BiquadsContext *p = ctx->priv;
405 static const AVFilterPad inputs[] = {
408 .type = AVMEDIA_TYPE_AUDIO,
409 .filter_frame = filter_frame,
414 static const AVFilterPad outputs[] = {
417 .type = AVMEDIA_TYPE_AUDIO,
418 .config_props = config_output,
423 #define OFFSET(x) offsetof(BiquadsContext, x)
424 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
426 #define DEFINE_BIQUAD_FILTER(name_, description_) \
427 AVFILTER_DEFINE_CLASS(name_); \
428 static av_cold int name_##_init(AVFilterContext *ctx, const char *args) \
430 BiquadsContext *p = ctx->priv; \
431 p->class = &name_##_class; \
432 p->filter_type = name_; \
433 return init(ctx, args); \
436 AVFilter avfilter_af_##name_ = { \
438 .description = NULL_IF_CONFIG_SMALL(description_), \
439 .priv_size = sizeof(BiquadsContext), \
440 .init = name_##_init, \
442 .query_formats = query_formats, \
444 .outputs = outputs, \
445 .priv_class = &name_##_class, \
448 #if CONFIG_EQUALIZER_FILTER
449 static const AVOption equalizer_options[] = {
450 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 999999, FLAGS},
451 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 999999, FLAGS},
452 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
453 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
454 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
455 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
456 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
457 {"width", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 999, FLAGS},
458 {"w", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 999, FLAGS},
459 {"gain", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
460 {"g", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
464 DEFINE_BIQUAD_FILTER(equalizer, "Apply two-pole peaking equalization (EQ) filter.");
465 #endif /* CONFIG_EQUALIZER_FILTER */
466 #if CONFIG_BASS_FILTER
467 static const AVOption bass_options[] = {
468 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 0, 999999, FLAGS},
469 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 0, 999999, FLAGS},
470 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
471 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
472 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
473 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
474 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
475 {"width", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS},
476 {"w", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS},
477 {"gain", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
478 {"g", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
482 DEFINE_BIQUAD_FILTER(bass, "Boost or cut lower frequencies.");
483 #endif /* CONFIG_BASS_FILTER */
484 #if CONFIG_TREBLE_FILTER
485 static const AVOption treble_options[] = {
486 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
487 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
488 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
489 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
490 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
491 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
492 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
493 {"width", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS},
494 {"w", "set shelf transition steep", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 99999, FLAGS},
495 {"gain", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
496 {"g", "set gain", OFFSET(gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -900, 900, FLAGS},
500 DEFINE_BIQUAD_FILTER(treble, "Boost or cut upper frequencies.");
501 #endif /* CONFIG_TREBLE_FILTER */
502 #if CONFIG_BANDPASS_FILTER
503 static const AVOption bandpass_options[] = {
504 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
505 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
506 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
507 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
508 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
509 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
510 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
511 {"width", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 999, FLAGS},
512 {"w", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 999, FLAGS},
513 {"csg", "use constant skirt gain", OFFSET(csg), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS},
517 DEFINE_BIQUAD_FILTER(bandpass, "Apply a two-pole Butterworth band-pass filter.");
518 #endif /* CONFIG_BANDPASS_FILTER */
519 #if CONFIG_BANDREJECT_FILTER
520 static const AVOption bandreject_options[] = {
521 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
522 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
523 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
524 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
525 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
526 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
527 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
528 {"width", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 999, FLAGS},
529 {"w", "set band-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 999, FLAGS},
533 DEFINE_BIQUAD_FILTER(bandreject, "Apply a two-pole Butterworth band-reject filter.");
534 #endif /* CONFIG_BANDREJECT_FILTER */
535 #if CONFIG_LOWPASS_FILTER
536 static const AVOption lowpass_options[] = {
537 {"frequency", "set frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=500}, 0, 999999, FLAGS},
538 {"f", "set frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=500}, 0, 999999, FLAGS},
539 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
540 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
541 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
542 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
543 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
544 {"width", "set width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.707}, 0, 99999, FLAGS},
545 {"w", "set width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.707}, 0, 99999, FLAGS},
546 {"poles", "set number of poles", OFFSET(poles), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, FLAGS},
547 {"p", "set number of poles", OFFSET(poles), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, FLAGS},
551 DEFINE_BIQUAD_FILTER(lowpass, "Apply a low-pass filter with 3dB point frequency.");
552 #endif /* CONFIG_LOWPASS_FILTER */
553 #if CONFIG_HIGHPASS_FILTER
554 static const AVOption highpass_options[] = {
555 {"frequency", "set frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
556 {"f", "set frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
557 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=QFACTOR}, HZ, SLOPE, FLAGS, "width_type"},
558 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
559 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
560 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
561 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
562 {"width", "set width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.707}, 0, 99999, FLAGS},
563 {"w", "set width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=0.707}, 0, 99999, FLAGS},
564 {"poles", "set number of poles", OFFSET(poles), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, FLAGS},
565 {"p", "set number of poles", OFFSET(poles), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, FLAGS},
569 DEFINE_BIQUAD_FILTER(highpass, "Apply a high-pass filter with 3dB point frequency.");
570 #endif /* CONFIG_HIGHPASS_FILTER */
571 #if CONFIG_ALLPASS_FILTER
572 static const AVOption allpass_options[] = {
573 {"frequency", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
574 {"f", "set central frequency", OFFSET(frequency), AV_OPT_TYPE_DOUBLE, {.dbl=3000}, 0, 999999, FLAGS},
575 {"width_type", "set filter-width type", OFFSET(width_type), AV_OPT_TYPE_INT, {.i64=HZ}, HZ, SLOPE, FLAGS, "width_type"},
576 {"h", "Hz", 0, AV_OPT_TYPE_CONST, {.i64=HZ}, 0, 0, FLAGS, "width_type"},
577 {"q", "Q-Factor", 0, AV_OPT_TYPE_CONST, {.i64=QFACTOR}, 0, 0, FLAGS, "width_type"},
578 {"o", "octave", 0, AV_OPT_TYPE_CONST, {.i64=OCTAVE}, 0, 0, FLAGS, "width_type"},
579 {"s", "slope", 0, AV_OPT_TYPE_CONST, {.i64=SLOPE}, 0, 0, FLAGS, "width_type"},
580 {"width", "set filter-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=707.1}, 0, 99999, FLAGS},
581 {"w", "set filter-width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=707.1}, 0, 99999, FLAGS},
585 DEFINE_BIQUAD_FILTER(allpass, "Apply a two-pole all-pass filter.");
586 #endif /* CONFIG_ALLPASS_FILTER */
587 #if CONFIG_BIQUAD_FILTER
588 static const AVOption biquad_options[] = {
589 {"a0", NULL, OFFSET(a0), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
590 {"a1", NULL, OFFSET(a1), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
591 {"a2", NULL, OFFSET(a2), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
592 {"b0", NULL, OFFSET(b0), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
593 {"b1", NULL, OFFSET(b1), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
594 {"b2", NULL, OFFSET(b2), AV_OPT_TYPE_DOUBLE, {.dbl=1}, INT16_MAX, INT16_MAX, FLAGS},
598 DEFINE_BIQUAD_FILTER(biquad, "Apply a biquad IIR filter with the given coefficients.");
599 #endif /* CONFIG_BIQUAD_FILTER */