git.sesse.net Git - ffmpeg/blob - libavfilter/af_silenceremove.c

   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
  33 enum SilenceDetect {
  34     D_PEAK,
  35     D_RMS,
  36 };
  37
  38 enum ThresholdMode {
  39     T_ANY,
  40     T_ALL,
  41 };
  42
  43 enum SilenceMode {
  44     SILENCE_TRIM,
  45     SILENCE_TRIM_FLUSH,
  46     SILENCE_COPY,
  47     SILENCE_COPY_FLUSH,
  48     SILENCE_STOP
  49 };
  50
  51 typedef struct SilenceRemoveContext {
  52     const AVClass *class;
  53
  54     enum SilenceMode mode;
  55
  56     int start_periods;
  57     int64_t start_duration;
  58     int64_t start_duration_opt;
  59     double start_threshold;
  60     int64_t start_silence;
  61     int64_t start_silence_opt;
  62     int start_mode;
  63
  64     int stop_periods;
  65     int64_t stop_duration;
  66     int64_t stop_duration_opt;
  67     double stop_threshold;
  68     int64_t stop_silence;
  69     int64_t stop_silence_opt;
  70     int stop_mode;
  71
  72     double *start_holdoff;
  73     double *start_silence_hold;
  74     size_t start_holdoff_offset;
  75     size_t start_holdoff_end;
  76     size_t start_silence_offset;
  77     size_t start_silence_end;
  78     int    start_found_periods;
  79
  80     double *stop_holdoff;
  81     double *stop_silence_hold;
  82     size_t stop_holdoff_offset;
  83     size_t stop_holdoff_end;
  84     size_t stop_silence_offset;
  85     size_t stop_silence_end;
  86     int    stop_found_periods;
  87
  88     double window_ratio;
  89     double *window;
  90     double *window_current;
  91     double *window_end;
  92     int window_size;
  93     double sum;
  94
  95     int restart;
  96     int64_t next_pts;
  97
  98     int detection;
  99     void (*update)(struct SilenceRemoveContext *s, double sample);
 100     double(*compute)(struct SilenceRemoveContext *s, double sample);
 101 } SilenceRemoveContext;
 102
 103 #define OFFSET(x) offsetof(SilenceRemoveContext, x)
 104 #define AF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
 105
 106 static const AVOption silenceremove_options[] = {
 107     { "start_periods",   NULL,                                                 OFFSET(start_periods),       AV_OPT_TYPE_INT,      {.i64=0},     0,      9000, AF },
 108     { "start_duration",  "set start duration of non-silence part",             OFFSET(start_duration_opt),  AV_OPT_TYPE_DURATION, {.i64=0},     0, INT32_MAX, AF },
 109     { "start_threshold", "set threshold for start silence detection",          OFFSET(start_threshold),     AV_OPT_TYPE_DOUBLE,   {.dbl=0},     0,   DBL_MAX, AF },
 110     { "start_silence",   "set start duration of silence part to keep",         OFFSET(start_silence_opt),   AV_OPT_TYPE_DURATION, {.i64=0},     0, INT32_MAX, AF },
 111     { "start_mode",      "set which channel will trigger trimming from start", OFFSET(start_mode),          AV_OPT_TYPE_INT,      {.i64=T_ANY}, T_ANY, T_ALL, AF, "mode" },
 112     {   "any",           0,                                                    0,                           AV_OPT_TYPE_CONST,    {.i64=T_ANY}, 0,         0, AF, "mode" },
 113     {   "all",           0,                                                    0,                           AV_OPT_TYPE_CONST,    {.i64=T_ALL}, 0,         0, AF, "mode" },
 114     { "stop_periods",    NULL,                                                 OFFSET(stop_periods),        AV_OPT_TYPE_INT,      {.i64=0}, -9000,      9000, AF },
 115     { "stop_duration",   "set stop duration of non-silence part",              OFFSET(stop_duration_opt),   AV_OPT_TYPE_DURATION, {.i64=0},     0, INT32_MAX, AF },
 116     { "stop_threshold",  "set threshold for stop silence detection",           OFFSET(stop_threshold),      AV_OPT_TYPE_DOUBLE,   {.dbl=0},     0,   DBL_MAX, AF },
 117     { "stop_silence",    "set stop duration of silence part to keep",          OFFSET(stop_silence_opt),    AV_OPT_TYPE_DURATION, {.i64=0},     0, INT32_MAX, AF },
 118     { "stop_mode",       "set which channel will trigger trimming from end",   OFFSET(stop_mode),           AV_OPT_TYPE_INT,      {.i64=T_ANY}, T_ANY, T_ALL, AF, "mode" },
 119     { "detection",       "set how silence is detected",                        OFFSET(detection),           AV_OPT_TYPE_INT,      {.i64=D_RMS}, D_PEAK,D_RMS, AF, "detection" },
 120     {   "peak",          "use absolute values of samples",                     0,                           AV_OPT_TYPE_CONST,    {.i64=D_PEAK},0,         0, AF, "detection" },
 121     {   "rms",           "use squared values of samples",                      0,                           AV_OPT_TYPE_CONST,    {.i64=D_RMS}, 0,         0, AF, "detection" },
 122     { "window",          "set duration of window in seconds",                  OFFSET(window_ratio),        AV_OPT_TYPE_DOUBLE,   {.dbl=0.02},  0,        10, AF },
 123     { NULL }
 124 };
 125
 126 AVFILTER_DEFINE_CLASS(silenceremove);
 127
 128 static double compute_peak(SilenceRemoveContext *s, double sample)
 129 {
 130     double new_sum;
 131
 132     new_sum  = s->sum;
 133     new_sum -= *s->window_current;
 134     new_sum += fabs(sample);
 135
 136     return new_sum / s->window_size;
 137 }
 138
 139 static void update_peak(SilenceRemoveContext *s, double sample)
 140 {
 141     s->sum -= *s->window_current;
 142     *s->window_current = fabs(sample);
 143     s->sum += *s->window_current;
 144
 145     s->window_current++;
 146     if (s->window_current >= s->window_end)
 147         s->window_current = s->window;
 148 }
 149
 150 static double compute_rms(SilenceRemoveContext *s, double sample)
 151 {
 152     double new_sum;
 153
 154     new_sum  = s->sum;
 155     new_sum -= *s->window_current;
 156     new_sum += sample * sample;
 157
 158     return sqrt(new_sum / s->window_size);
 159 }
 160
 161 static void update_rms(SilenceRemoveContext *s, double sample)
 162 {
 163     s->sum -= *s->window_current;
 164     *s->window_current = sample * sample;
 165     s->sum += *s->window_current;
 166
 167     s->window_current++;
 168     if (s->window_current >= s->window_end)
 169         s->window_current = s->window;
 170 }
 171
 172 static av_cold int init(AVFilterContext *ctx)
 173 {
 174     SilenceRemoveContext *s = ctx->priv;
 175
 176     if (s->stop_periods < 0) {
 177         s->stop_periods = -s->stop_periods;
 178         s->restart = 1;
 179     }
 180
 181     switch (s->detection) {
 182     case D_PEAK:
 183         s->update = update_peak;
 184         s->compute = compute_peak;
 185         break;
 186     case D_RMS:
 187         s->update = update_rms;
 188         s->compute = compute_rms;
 189         break;
 190     }
 191
 192     return 0;
 193 }
 194
 195 static void clear_window(SilenceRemoveContext *s)
 196 {
 197     memset(s->window, 0, s->window_size * sizeof(*s->window));
 198
 199     s->window_current = s->window;
 200     s->window_end = s->window + s->window_size;
 201     s->sum = 0;
 202 }
 203
 204 static int config_input(AVFilterLink *inlink)
 205 {
 206     AVFilterContext *ctx = inlink->dst;
 207     SilenceRemoveContext *s = ctx->priv;
 208
 209     s->window_size = FFMAX((inlink->sample_rate * s->window_ratio), 1) * inlink->channels;
 210     s->window = av_malloc_array(s->window_size, sizeof(*s->window));
 211     if (!s->window)
 212         return AVERROR(ENOMEM);
 213
 214     clear_window(s);
 215
 216     s->start_duration = av_rescale(s->start_duration_opt, inlink->sample_rate,
 217                                    AV_TIME_BASE);
 218     s->start_silence  = av_rescale(s->start_silence_opt, inlink->sample_rate,
 219                                    AV_TIME_BASE);
 220     s->stop_duration  = av_rescale(s->stop_duration_opt, inlink->sample_rate,
 221                                    AV_TIME_BASE);
 222     s->stop_silence   = av_rescale(s->stop_silence_opt, inlink->sample_rate,
 223                                    AV_TIME_BASE);
 224
 225     s->start_holdoff = av_malloc_array(FFMAX(s->start_duration, 1),
 226                                        sizeof(*s->start_holdoff) *
 227                                        inlink->channels);
 228     if (!s->start_holdoff)
 229         return AVERROR(ENOMEM);
 230
 231     s->start_silence_hold = av_malloc_array(FFMAX(s->start_silence, 1),
 232                                             sizeof(*s->start_silence_hold) *
 233                                             inlink->channels);
 234     if (!s->start_silence_hold)
 235         return AVERROR(ENOMEM);
 236
 237     s->start_holdoff_offset = 0;
 238     s->start_holdoff_end    = 0;
 239     s->start_found_periods  = 0;
 240
 241     s->stop_holdoff = av_malloc_array(FFMAX(s->stop_duration, 1),
 242                                       sizeof(*s->stop_holdoff) *
 243                                       inlink->channels);
 244     if (!s->stop_holdoff)
 245         return AVERROR(ENOMEM);
 246
 247     s->stop_silence_hold = av_malloc_array(FFMAX(s->stop_silence, 1),
 248                                            sizeof(*s->stop_silence_hold) *
 249                                            inlink->channels);
 250     if (!s->stop_silence_hold)
 251         return AVERROR(ENOMEM);
 252
 253     s->stop_holdoff_offset = 0;
 254     s->stop_holdoff_end    = 0;
 255     s->stop_found_periods  = 0;
 256
 257     if (s->start_periods)
 258         s->mode = SILENCE_TRIM;
 259     else
 260         s->mode = SILENCE_COPY;
 261
 262     return 0;
 263 }
 264
 265 static void flush(SilenceRemoveContext *s,
 266                   AVFrame *out, AVFilterLink *outlink,
 267                   int *nb_samples_written, int *ret, int flush_silence)
 268 {
 269     AVFrame *silence;
 270
 271     if (*nb_samples_written) {
 272         out->nb_samples = *nb_samples_written / outlink->channels;
 273
 274         out->pts = s->next_pts;
 275         s->next_pts += av_rescale_q(out->nb_samples,
 276                                     (AVRational){1, outlink->sample_rate},
 277                                     outlink->time_base);
 278
 279         *ret = ff_filter_frame(outlink, out);
 280         if (*ret < 0)
 281             return;
 282         *nb_samples_written = 0;
 283     } else {
 284         av_frame_free(&out);
 285     }
 286
 287     if (s->stop_silence_end <= 0 || !flush_silence)
 288         return;
 289
 290     silence = ff_get_audio_buffer(outlink, s->stop_silence_end / outlink->channels);
 291     if (!silence) {
 292         *ret = AVERROR(ENOMEM);
 293         return;
 294     }
 295
 296     if (s->stop_silence_offset < s->stop_silence_end) {
 297         memcpy(silence->data[0],
 298                &s->stop_silence_hold[s->stop_silence_offset],
 299                (s->stop_silence_end - s->stop_silence_offset) * sizeof(double));
 300     }
 301
 302     if (s->stop_silence_offset > 0) {
 303         memcpy(silence->data[0] + (s->stop_silence_end - s->stop_silence_offset) * sizeof(double),
 304                &s->stop_silence_hold[0],
 305                s->stop_silence_offset * sizeof(double));
 306     }
 307
 308     s->stop_silence_offset = 0;
 309     s->stop_silence_end = 0;
 310
 311     silence->pts = s->next_pts;
 312     s->next_pts += av_rescale_q(silence->nb_samples,
 313                                 (AVRational){1, outlink->sample_rate},
 314                                 outlink->time_base);
 315
 316     *ret = ff_filter_frame(outlink, silence);
 317 }
 318
 319 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 320 {
 321     AVFilterContext *ctx = inlink->dst;
 322     AVFilterLink *outlink = ctx->outputs[0];
 323     SilenceRemoveContext *s = ctx->priv;
 324     int i, j, threshold, ret = 0;
 325     int nbs, nb_samples_read, nb_samples_written;
 326     double *obuf, *ibuf = (double *)in->data[0];
 327     AVFrame *out;
 328
 329     nb_samples_read = nb_samples_written = 0;
 330
 331     switch (s->mode) {
 332     case SILENCE_TRIM:
 333 silence_trim:
 334         nbs = in->nb_samples - nb_samples_read / outlink->channels;
 335         if (!nbs)
 336             break;
 337
 338         for (i = 0; i < nbs; i++) {
 339             if (s->start_mode == T_ANY) {
 340                 threshold = 0;
 341                 for (j = 0; j < outlink->channels; j++) {
 342                     threshold |= s->compute(s, ibuf[j]) > s->start_threshold;
 343                 }
 344             } else {
 345                 threshold = 1;
 346                 for (j = 0; j < outlink->channels; j++) {
 347                     threshold &= s->compute(s, ibuf[j]) > s->start_threshold;
 348                 }
 349             }
 350
 351             if (threshold) {
 352                 for (j = 0; j < outlink->channels; j++) {
 353                     s->update(s, *ibuf);
 354                     s->start_holdoff[s->start_holdoff_end++] = *ibuf++;
 355                 }
 356                 nb_samples_read += outlink->channels;
 357
 358                 if (s->start_holdoff_end >= s->start_duration * outlink->channels) {
 359                     if (++s->start_found_periods >= s->start_periods) {
 360                         s->mode = SILENCE_TRIM_FLUSH;
 361                         goto silence_trim_flush;
 362                     }
 363
 364                     s->start_holdoff_offset = 0;
 365                     s->start_holdoff_end = 0;
 366                     s->start_silence_offset = 0;
 367                     s->start_silence_end = 0;
 368                 }
 369             } else {
 370                 s->start_holdoff_end = 0;
 371
 372                 for (j = 0; j < outlink->channels; j++) {
 373                     s->update(s, ibuf[j]);
 374                     if (s->start_silence) {
 375                         s->start_silence_hold[s->start_silence_offset++] = ibuf[j];
 376                         s->start_silence_end = FFMIN(s->start_silence_end + 1, outlink->channels * s->start_silence);
 377                         if (s->start_silence_offset >= outlink->channels * s->start_silence) {
 378                             s->start_silence_offset = 0;
 379                         }
 380                     }
 381                 }
 382
 383                 ibuf += outlink->channels;
 384                 nb_samples_read += outlink->channels;
 385             }
 386         }
 387         break;
 388
 389     case SILENCE_TRIM_FLUSH:
 390 silence_trim_flush:
 391         nbs  = s->start_holdoff_end - s->start_holdoff_offset;
 392         nbs -= nbs % outlink->channels;
 393         if (!nbs)
 394             break;
 395
 396         out = ff_get_audio_buffer(outlink, nbs / outlink->channels + s->start_silence_end / outlink->channels);
 397         if (!out) {
 398             av_frame_free(&in);
 399             return AVERROR(ENOMEM);
 400         }
 401
 402         if (s->start_silence_end > 0) {
 403             if (s->start_silence_offset < s->start_silence_end) {
 404                 memcpy(out->data[0],
 405                        &s->start_silence_hold[s->start_silence_offset],
 406                        (s->start_silence_end - s->start_silence_offset) * sizeof(double));
 407             }
 408
 409             if (s->start_silence_offset > 0) {
 410                 memcpy(out->data[0] + (s->start_silence_end - s->start_silence_offset) * sizeof(double),
 411                        &s->start_silence_hold[0],
 412                        s->start_silence_offset * sizeof(double));
 413             }
 414         }
 415
 416         memcpy(out->data[0] + s->start_silence_end * sizeof(double),
 417                &s->start_holdoff[s->start_holdoff_offset],
 418                nbs * sizeof(double));
 419
 420         out->pts = s->next_pts;
 421         s->next_pts += av_rescale_q(out->nb_samples,
 422                                     (AVRational){1, outlink->sample_rate},
 423                                     outlink->time_base);
 424
 425         s->start_holdoff_offset += nbs;
 426
 427         ret = ff_filter_frame(outlink, out);
 428
 429         if (s->start_holdoff_offset == s->start_holdoff_end) {
 430             s->start_holdoff_offset = 0;
 431             s->start_holdoff_end = 0;
 432             s->start_silence_offset = 0;
 433             s->start_silence_end = 0;
 434             s->mode = SILENCE_COPY;
 435             goto silence_copy;
 436         }
 437         break;
 438
 439     case SILENCE_COPY:
 440 silence_copy:
 441         nbs = in->nb_samples - nb_samples_read / outlink->channels;
 442         if (!nbs)
 443             break;
 444
 445         out = ff_get_audio_buffer(outlink, nbs);
 446         if (!out) {
 447             av_frame_free(&in);
 448             return AVERROR(ENOMEM);
 449         }
 450         obuf = (double *)out->data[0];
 451
 452         if (s->stop_periods) {
 453             for (i = 0; i < nbs; i++) {
 454                 if (s->stop_mode == T_ANY) {
 455                     threshold = 0;
 456                     for (j = 0; j < outlink->channels; j++) {
 457                         threshold |= s->compute(s, ibuf[j]) > s->stop_threshold;
 458                     }
 459                 } else {
 460                     threshold = 1;
 461                     for (j = 0; j < outlink->channels; j++) {
 462                         threshold &= s->compute(s, ibuf[j]) > s->stop_threshold;
 463                     }
 464                 }
 465
 466                 if (threshold && s->stop_holdoff_end && !s->stop_silence) {
 467                     s->mode = SILENCE_COPY_FLUSH;
 468                     flush(s, out, outlink, &nb_samples_written, &ret, 0);
 469                     goto silence_copy_flush;
 470                 } else if (threshold) {
 471                     for (j = 0; j < outlink->channels; j++) {
 472                         s->update(s, *ibuf);
 473                         *obuf++ = *ibuf++;
 474                     }
 475                     nb_samples_read    += outlink->channels;
 476                     nb_samples_written += outlink->channels;
 477                 } else if (!threshold) {
 478                     for (j = 0; j < outlink->channels; j++) {
 479                         s->update(s, *ibuf);
 480                         if (s->stop_silence) {
 481                             s->stop_silence_hold[s->stop_silence_offset++] = *ibuf;
 482                             s->stop_silence_end = FFMIN(s->stop_silence_end + 1, outlink->channels * s->stop_silence);
 483                             if (s->stop_silence_offset >= outlink->channels * s->stop_silence) {
 484                                 s->stop_silence_offset = 0;
 485                             }
 486                         }
 487
 488                         s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++;
 489                     }
 490                     nb_samples_read += outlink->channels;
 491
 492                     if (s->stop_holdoff_end >= s->stop_duration * outlink->channels) {
 493                         if (++s->stop_found_periods >= s->stop_periods) {
 494                             s->stop_holdoff_offset = 0;
 495                             s->stop_holdoff_end = 0;
 496
 497                             if (!s->restart) {
 498                                 s->mode = SILENCE_STOP;
 499                                 flush(s, out, outlink, &nb_samples_written, &ret, 1);
 500                                 goto silence_stop;
 501                             } else {
 502                                 s->stop_found_periods = 0;
 503                                 s->start_found_periods = 0;
 504                                 s->start_holdoff_offset = 0;
 505                                 s->start_holdoff_end = 0;
 506                                 s->start_silence_offset = 0;
 507                                 s->start_silence_end = 0;
 508                                 clear_window(s);
 509                                 s->mode = SILENCE_TRIM;
 510                                 flush(s, out, outlink, &nb_samples_written, &ret, 1);
 511                                 goto silence_trim;
 512                             }
 513                         }
 514                         s->mode = SILENCE_COPY_FLUSH;
 515                         flush(s, out, outlink, &nb_samples_written, &ret, 0);
 516                         goto silence_copy_flush;
 517                     }
 518                 }
 519             }
 520             flush(s, out, outlink, &nb_samples_written, &ret, 0);
 521         } else {
 522             memcpy(obuf, ibuf, sizeof(double) * nbs * outlink->channels);
 523
 524             out->pts = s->next_pts;
 525             s->next_pts += av_rescale_q(out->nb_samples,
 526                                         (AVRational){1, outlink->sample_rate},
 527                                         outlink->time_base);
 528
 529             ret = ff_filter_frame(outlink, out);
 530         }
 531         break;
 532
 533     case SILENCE_COPY_FLUSH:
 534 silence_copy_flush:
 535         nbs  = s->stop_holdoff_end - s->stop_holdoff_offset;
 536         nbs -= nbs % outlink->channels;
 537         if (!nbs)
 538             break;
 539
 540         out = ff_get_audio_buffer(outlink, nbs / outlink->channels);
 541         if (!out) {
 542             av_frame_free(&in);
 543             return AVERROR(ENOMEM);
 544         }
 545
 546         memcpy(out->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
 547                nbs * sizeof(double));
 548         s->stop_holdoff_offset += nbs;
 549
 550         out->pts = s->next_pts;
 551         s->next_pts += av_rescale_q(out->nb_samples,
 552                                     (AVRational){1, outlink->sample_rate},
 553                                     outlink->time_base);
 554
 555         ret = ff_filter_frame(outlink, out);
 556
 557         if (s->stop_holdoff_offset == s->stop_holdoff_end) {
 558             s->stop_holdoff_offset = 0;
 559             s->stop_holdoff_end = 0;
 560             s->stop_silence_offset = 0;
 561             s->stop_silence_end = 0;
 562             s->mode = SILENCE_COPY;
 563             goto silence_copy;
 564         }
 565         break;
 566     case SILENCE_STOP:
 567 silence_stop:
 568         break;
 569     }
 570
 571     av_frame_free(&in);
 572
 573     return ret;
 574 }
 575
 576 static int request_frame(AVFilterLink *outlink)
 577 {
 578     AVFilterContext *ctx = outlink->src;
 579     SilenceRemoveContext *s = ctx->priv;
 580     int ret;
 581
 582     ret = ff_request_frame(ctx->inputs[0]);
 583     if (ret == AVERROR_EOF && (s->mode == SILENCE_COPY_FLUSH ||
 584                                s->mode == SILENCE_COPY)) {
 585         int nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
 586         if (nbs) {
 587             AVFrame *frame;
 588
 589             frame = ff_get_audio_buffer(outlink, nbs / outlink->channels);
 590             if (!frame)
 591                 return AVERROR(ENOMEM);
 592
 593             memcpy(frame->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
 594                    nbs * sizeof(double));
 595
 596             frame->pts = s->next_pts;
 597             s->next_pts += av_rescale_q(frame->nb_samples,
 598                                         (AVRational){1, outlink->sample_rate},
 599                                         outlink->time_base);
 600
 601             ret = ff_filter_frame(outlink, frame);
 602         }
 603         s->mode = SILENCE_STOP;
 604     }
 605     return ret;
 606 }
 607
 608 static int query_formats(AVFilterContext *ctx)
 609 {
 610     AVFilterFormats *formats = NULL;
 611     AVFilterChannelLayouts *layouts = NULL;
 612     static const enum AVSampleFormat sample_fmts[] = {
 613         AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_NONE
 614     };
 615     int ret;
 616
 617     layouts = ff_all_channel_counts();
 618     if (!layouts)
 619         return AVERROR(ENOMEM);
 620     ret = ff_set_common_channel_layouts(ctx, layouts);
 621     if (ret < 0)
 622         return ret;
 623
 624     formats = ff_make_format_list(sample_fmts);
 625     if (!formats)
 626         return AVERROR(ENOMEM);
 627     ret = ff_set_common_formats(ctx, formats);
 628     if (ret < 0)
 629         return ret;
 630
 631     formats = ff_all_samplerates();
 632     if (!formats)
 633         return AVERROR(ENOMEM);
 634     return ff_set_common_samplerates(ctx, formats);
 635 }
 636
 637 static av_cold void uninit(AVFilterContext *ctx)
 638 {
 639     SilenceRemoveContext *s = ctx->priv;
 640
 641     av_freep(&s->start_holdoff);
 642     av_freep(&s->start_silence_hold);
 643     av_freep(&s->stop_holdoff);
 644     av_freep(&s->stop_silence_hold);
 645     av_freep(&s->window);
 646 }
 647
 648 static const AVFilterPad silenceremove_inputs[] = {
 649     {
 650         .name         = "default",
 651         .type         = AVMEDIA_TYPE_AUDIO,
 652         .config_props = config_input,
 653         .filter_frame = filter_frame,
 654     },
 655     { NULL }
 656 };
 657
 658 static const AVFilterPad silenceremove_outputs[] = {
 659     {
 660         .name          = "default",
 661         .type          = AVMEDIA_TYPE_AUDIO,
 662         .request_frame = request_frame,
 663     },
 664     { NULL }
 665 };
 666
 667 AVFilter ff_af_silenceremove = {
 668     .name          = "silenceremove",
 669     .description   = NULL_IF_CONFIG_SMALL("Remove silence."),
 670     .priv_size     = sizeof(SilenceRemoveContext),
 671     .priv_class    = &silenceremove_class,
 672     .init          = init,
 673     .uninit        = uninit,
 674     .query_formats = query_formats,
 675     .inputs        = silenceremove_inputs,
 676     .outputs       = silenceremove_outputs,
 677 };