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path: root/libavfilter/af_silenceremove.c (plain)
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1/*
2 * Copyright (c) 2001 Heikki Leinonen
3 * Copyright (c) 2001 Chris Bagwell
4 * Copyright (c) 2003 Donnie Smith
5 * Copyright (c) 2014 Paul B Mahol
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include <float.h> /* DBL_MAX */
25
26#include "libavutil/opt.h"
27#include "libavutil/timestamp.h"
28#include "audio.h"
29#include "formats.h"
30#include "avfilter.h"
31#include "internal.h"
32
33enum SilenceMode {
34 SILENCE_TRIM,
35 SILENCE_TRIM_FLUSH,
36 SILENCE_COPY,
37 SILENCE_COPY_FLUSH,
38 SILENCE_STOP
39};
40
41typedef struct SilenceRemoveContext {
42 const AVClass *class;
43
44 enum SilenceMode mode;
45
46 int start_periods;
47 int64_t start_duration;
48 double start_threshold;
49
50 int stop_periods;
51 int64_t stop_duration;
52 double stop_threshold;
53
54 double *start_holdoff;
55 size_t start_holdoff_offset;
56 size_t start_holdoff_end;
57 int start_found_periods;
58
59 double *stop_holdoff;
60 size_t stop_holdoff_offset;
61 size_t stop_holdoff_end;
62 int stop_found_periods;
63
64 double window_ratio;
65 double *window;
66 double *window_current;
67 double *window_end;
68 int window_size;
69 double sum;
70
71 int leave_silence;
72 int restart;
73 int64_t next_pts;
74
75 int detection;
76 void (*update)(struct SilenceRemoveContext *s, double sample);
77 double(*compute)(struct SilenceRemoveContext *s, double sample);
78} SilenceRemoveContext;
79
80#define OFFSET(x) offsetof(SilenceRemoveContext, x)
81#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
82static const AVOption silenceremove_options[] = {
83 { "start_periods", NULL, OFFSET(start_periods), AV_OPT_TYPE_INT, {.i64=0}, 0, 9000, FLAGS },
84 { "start_duration", NULL, OFFSET(start_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS },
85 { "start_threshold", NULL, OFFSET(start_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS },
86 { "stop_periods", NULL, OFFSET(stop_periods), AV_OPT_TYPE_INT, {.i64=0}, -9000, 9000, FLAGS },
87 { "stop_duration", NULL, OFFSET(stop_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS },
88 { "stop_threshold", NULL, OFFSET(stop_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS },
89 { "leave_silence", NULL, OFFSET(leave_silence), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
90 { "detection", NULL, OFFSET(detection), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "detection" },
91 { "peak", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "detection" },
92 { "rms", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "detection" },
93 { "window", NULL, OFFSET(window_ratio), AV_OPT_TYPE_DOUBLE, {.dbl=0.02}, 0, 10, FLAGS },
94 { NULL }
95};
96
97AVFILTER_DEFINE_CLASS(silenceremove);
98
99static double compute_peak(SilenceRemoveContext *s, double sample)
100{
101 double new_sum;
102
103 new_sum = s->sum;
104 new_sum -= *s->window_current;
105 new_sum += fabs(sample);
106
107 return new_sum / s->window_size;
108}
109
110static void update_peak(SilenceRemoveContext *s, double sample)
111{
112 s->sum -= *s->window_current;
113 *s->window_current = fabs(sample);
114 s->sum += *s->window_current;
115
116 s->window_current++;
117 if (s->window_current >= s->window_end)
118 s->window_current = s->window;
119}
120
121static double compute_rms(SilenceRemoveContext *s, double sample)
122{
123 double new_sum;
124
125 new_sum = s->sum;
126 new_sum -= *s->window_current;
127 new_sum += sample * sample;
128
129 return sqrt(new_sum / s->window_size);
130}
131
132static void update_rms(SilenceRemoveContext *s, double sample)
133{
134 s->sum -= *s->window_current;
135 *s->window_current = sample * sample;
136 s->sum += *s->window_current;
137
138 s->window_current++;
139 if (s->window_current >= s->window_end)
140 s->window_current = s->window;
141}
142
143static av_cold int init(AVFilterContext *ctx)
144{
145 SilenceRemoveContext *s = ctx->priv;
146
147 if (s->stop_periods < 0) {
148 s->stop_periods = -s->stop_periods;
149 s->restart = 1;
150 }
151
152 switch (s->detection) {
153 case 0:
154 s->update = update_peak;
155 s->compute = compute_peak;
156 break;
157 case 1:
158 s->update = update_rms;
159 s->compute = compute_rms;
160 break;
161 };
162
163 return 0;
164}
165
166static void clear_window(SilenceRemoveContext *s)
167{
168 memset(s->window, 0, s->window_size * sizeof(*s->window));
169
170 s->window_current = s->window;
171 s->window_end = s->window + s->window_size;
172 s->sum = 0;
173}
174
175static int config_input(AVFilterLink *inlink)
176{
177 AVFilterContext *ctx = inlink->dst;
178 SilenceRemoveContext *s = ctx->priv;
179
180 s->window_size = FFMAX((inlink->sample_rate * s->window_ratio), 1) * inlink->channels;
181 s->window = av_malloc_array(s->window_size, sizeof(*s->window));
182 if (!s->window)
183 return AVERROR(ENOMEM);
184
185 clear_window(s);
186
187 s->start_duration = av_rescale(s->start_duration, inlink->sample_rate,
188 AV_TIME_BASE);
189 s->stop_duration = av_rescale(s->stop_duration, inlink->sample_rate,
190 AV_TIME_BASE);
191
192 s->start_holdoff = av_malloc_array(FFMAX(s->start_duration, 1),
193 sizeof(*s->start_holdoff) *
194 inlink->channels);
195 if (!s->start_holdoff)
196 return AVERROR(ENOMEM);
197
198 s->start_holdoff_offset = 0;
199 s->start_holdoff_end = 0;
200 s->start_found_periods = 0;
201
202 s->stop_holdoff = av_malloc_array(FFMAX(s->stop_duration, 1),
203 sizeof(*s->stop_holdoff) *
204 inlink->channels);
205 if (!s->stop_holdoff)
206 return AVERROR(ENOMEM);
207
208 s->stop_holdoff_offset = 0;
209 s->stop_holdoff_end = 0;
210 s->stop_found_periods = 0;
211
212 if (s->start_periods)
213 s->mode = SILENCE_TRIM;
214 else
215 s->mode = SILENCE_COPY;
216
217 return 0;
218}
219
220static void flush(AVFrame *out, AVFilterLink *outlink,
221 int *nb_samples_written, int *ret)
222{
223 if (*nb_samples_written) {
224 out->nb_samples = *nb_samples_written / outlink->channels;
225 *ret = ff_filter_frame(outlink, out);
226 *nb_samples_written = 0;
227 } else {
228 av_frame_free(&out);
229 }
230}
231
232static int filter_frame(AVFilterLink *inlink, AVFrame *in)
233{
234 AVFilterContext *ctx = inlink->dst;
235 AVFilterLink *outlink = ctx->outputs[0];
236 SilenceRemoveContext *s = ctx->priv;
237 int i, j, threshold, ret = 0;
238 int nbs, nb_samples_read, nb_samples_written;
239 double *obuf, *ibuf = (double *)in->data[0];
240 AVFrame *out;
241
242 nb_samples_read = nb_samples_written = 0;
243
244 switch (s->mode) {
245 case SILENCE_TRIM:
246silence_trim:
247 nbs = in->nb_samples - nb_samples_read / inlink->channels;
248 if (!nbs)
249 break;
250
251 for (i = 0; i < nbs; i++) {
252 threshold = 0;
253 for (j = 0; j < inlink->channels; j++) {
254 threshold |= s->compute(s, ibuf[j]) > s->start_threshold;
255 }
256
257 if (threshold) {
258 for (j = 0; j < inlink->channels; j++) {
259 s->update(s, *ibuf);
260 s->start_holdoff[s->start_holdoff_end++] = *ibuf++;
261 }
262 nb_samples_read += inlink->channels;
263
264 if (s->start_holdoff_end >= s->start_duration * inlink->channels) {
265 if (++s->start_found_periods >= s->start_periods) {
266 s->mode = SILENCE_TRIM_FLUSH;
267 goto silence_trim_flush;
268 }
269
270 s->start_holdoff_offset = 0;
271 s->start_holdoff_end = 0;
272 }
273 } else {
274 s->start_holdoff_end = 0;
275
276 for (j = 0; j < inlink->channels; j++)
277 s->update(s, ibuf[j]);
278
279 ibuf += inlink->channels;
280 nb_samples_read += inlink->channels;
281 }
282 }
283 break;
284
285 case SILENCE_TRIM_FLUSH:
286silence_trim_flush:
287 nbs = s->start_holdoff_end - s->start_holdoff_offset;
288 nbs -= nbs % inlink->channels;
289 if (!nbs)
290 break;
291
292 out = ff_get_audio_buffer(inlink, nbs / inlink->channels);
293 if (!out) {
294 av_frame_free(&in);
295 return AVERROR(ENOMEM);
296 }
297
298 memcpy(out->data[0], &s->start_holdoff[s->start_holdoff_offset],
299 nbs * sizeof(double));
300 s->start_holdoff_offset += nbs;
301
302 ret = ff_filter_frame(outlink, out);
303
304 if (s->start_holdoff_offset == s->start_holdoff_end) {
305 s->start_holdoff_offset = 0;
306 s->start_holdoff_end = 0;
307 s->mode = SILENCE_COPY;
308 goto silence_copy;
309 }
310 break;
311
312 case SILENCE_COPY:
313silence_copy:
314 nbs = in->nb_samples - nb_samples_read / inlink->channels;
315 if (!nbs)
316 break;
317
318 out = ff_get_audio_buffer(inlink, nbs);
319 if (!out) {
320 av_frame_free(&in);
321 return AVERROR(ENOMEM);
322 }
323 obuf = (double *)out->data[0];
324
325 if (s->stop_periods) {
326 for (i = 0; i < nbs; i++) {
327 threshold = 1;
328 for (j = 0; j < inlink->channels; j++)
329 threshold &= s->compute(s, ibuf[j]) > s->stop_threshold;
330
331 if (threshold && s->stop_holdoff_end && !s->leave_silence) {
332 s->mode = SILENCE_COPY_FLUSH;
333 flush(out, outlink, &nb_samples_written, &ret);
334 goto silence_copy_flush;
335 } else if (threshold) {
336 for (j = 0; j < inlink->channels; j++) {
337 s->update(s, *ibuf);
338 *obuf++ = *ibuf++;
339 }
340 nb_samples_read += inlink->channels;
341 nb_samples_written += inlink->channels;
342 } else if (!threshold) {
343 for (j = 0; j < inlink->channels; j++) {
344 s->update(s, *ibuf);
345 if (s->leave_silence) {
346 *obuf++ = *ibuf;
347 nb_samples_written++;
348 }
349
350 s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++;
351 }
352 nb_samples_read += inlink->channels;
353
354 if (s->stop_holdoff_end >= s->stop_duration * inlink->channels) {
355 if (++s->stop_found_periods >= s->stop_periods) {
356 s->stop_holdoff_offset = 0;
357 s->stop_holdoff_end = 0;
358
359 if (!s->restart) {
360 s->mode = SILENCE_STOP;
361 flush(out, outlink, &nb_samples_written, &ret);
362 goto silence_stop;
363 } else {
364 s->stop_found_periods = 0;
365 s->start_found_periods = 0;
366 s->start_holdoff_offset = 0;
367 s->start_holdoff_end = 0;
368 clear_window(s);
369 s->mode = SILENCE_TRIM;
370 flush(out, outlink, &nb_samples_written, &ret);
371 goto silence_trim;
372 }
373 }
374 s->mode = SILENCE_COPY_FLUSH;
375 flush(out, outlink, &nb_samples_written, &ret);
376 goto silence_copy_flush;
377 }
378 }
379 }
380 flush(out, outlink, &nb_samples_written, &ret);
381 } else {
382 memcpy(obuf, ibuf, sizeof(double) * nbs * inlink->channels);
383 ret = ff_filter_frame(outlink, out);
384 }
385 break;
386
387 case SILENCE_COPY_FLUSH:
388silence_copy_flush:
389 nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
390 nbs -= nbs % inlink->channels;
391 if (!nbs)
392 break;
393
394 out = ff_get_audio_buffer(inlink, nbs / inlink->channels);
395 if (!out) {
396 av_frame_free(&in);
397 return AVERROR(ENOMEM);
398 }
399
400 memcpy(out->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
401 nbs * sizeof(double));
402 s->stop_holdoff_offset += nbs;
403
404 ret = ff_filter_frame(outlink, out);
405
406 if (s->stop_holdoff_offset == s->stop_holdoff_end) {
407 s->stop_holdoff_offset = 0;
408 s->stop_holdoff_end = 0;
409 s->mode = SILENCE_COPY;
410 goto silence_copy;
411 }
412 break;
413 case SILENCE_STOP:
414silence_stop:
415 break;
416 }
417
418 av_frame_free(&in);
419
420 return ret;
421}
422
423static int request_frame(AVFilterLink *outlink)
424{
425 AVFilterContext *ctx = outlink->src;
426 SilenceRemoveContext *s = ctx->priv;
427 int ret;
428
429 ret = ff_request_frame(ctx->inputs[0]);
430 if (ret == AVERROR_EOF && (s->mode == SILENCE_COPY_FLUSH ||
431 s->mode == SILENCE_COPY)) {
432 int nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
433 if (nbs) {
434 AVFrame *frame;
435
436 frame = ff_get_audio_buffer(outlink, nbs / outlink->channels);
437 if (!frame)
438 return AVERROR(ENOMEM);
439
440 memcpy(frame->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
441 nbs * sizeof(double));
442 ret = ff_filter_frame(ctx->inputs[0], frame);
443 }
444 s->mode = SILENCE_STOP;
445 }
446 return ret;
447}
448
449static int query_formats(AVFilterContext *ctx)
450{
451 AVFilterFormats *formats = NULL;
452 AVFilterChannelLayouts *layouts = NULL;
453 static const enum AVSampleFormat sample_fmts[] = {
454 AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_NONE
455 };
456 int ret;
457
458 layouts = ff_all_channel_counts();
459 if (!layouts)
460 return AVERROR(ENOMEM);
461 ret = ff_set_common_channel_layouts(ctx, layouts);
462 if (ret < 0)
463 return ret;
464
465 formats = ff_make_format_list(sample_fmts);
466 if (!formats)
467 return AVERROR(ENOMEM);
468 ret = ff_set_common_formats(ctx, formats);
469 if (ret < 0)
470 return ret;
471
472 formats = ff_all_samplerates();
473 if (!formats)
474 return AVERROR(ENOMEM);
475 return ff_set_common_samplerates(ctx, formats);
476}
477
478static av_cold void uninit(AVFilterContext *ctx)
479{
480 SilenceRemoveContext *s = ctx->priv;
481
482 av_freep(&s->start_holdoff);
483 av_freep(&s->stop_holdoff);
484 av_freep(&s->window);
485}
486
487static const AVFilterPad silenceremove_inputs[] = {
488 {
489 .name = "default",
490 .type = AVMEDIA_TYPE_AUDIO,
491 .config_props = config_input,
492 .filter_frame = filter_frame,
493 },
494 { NULL }
495};
496
497static const AVFilterPad silenceremove_outputs[] = {
498 {
499 .name = "default",
500 .type = AVMEDIA_TYPE_AUDIO,
501 .request_frame = request_frame,
502 },
503 { NULL }
504};
505
506AVFilter ff_af_silenceremove = {
507 .name = "silenceremove",
508 .description = NULL_IF_CONFIG_SMALL("Remove silence."),
509 .priv_size = sizeof(SilenceRemoveContext),
510 .priv_class = &silenceremove_class,
511 .init = init,
512 .uninit = uninit,
513 .query_formats = query_formats,
514 .inputs = silenceremove_inputs,
515 .outputs = silenceremove_outputs,
516};
517
generated by cgit at 2024-05-17 02:01:38 (GMT)