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

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 /**
  20  * @file
  21  * Crossover filter
  22  *
  23  * Split an audio stream into several bands.
  24  */
  25
  26 #include "libavutil/attributes.h"
  27 #include "libavutil/avstring.h"
  28 #include "libavutil/channel_layout.h"
  29 #include "libavutil/eval.h"
  30 #include "libavutil/float_dsp.h"
  31 #include "libavutil/internal.h"
  32 #include "libavutil/opt.h"
  33
  34 #include "audio.h"
  35 #include "avfilter.h"
  36 #include "formats.h"
  37 #include "internal.h"
  38
  39 #define MAX_SPLITS 16
  40 #define MAX_BANDS MAX_SPLITS + 1
  41
  42 typedef struct BiquadContext {
  43     double b0, b1, b2;
  44     double a1, a2;
  45     double z1, z2;
  46 } BiquadContext;
  47
  48 typedef struct CrossoverChannel {
  49     BiquadContext lp[MAX_BANDS][20];
  50     BiquadContext hp[MAX_BANDS][20];
  51     BiquadContext ap[MAX_BANDS][MAX_BANDS][20];
  52 } CrossoverChannel;
  53
  54 typedef struct AudioCrossoverContext {
  55     const AVClass *class;
  56
  57     char *splits_str;
  58     int order_opt;
  59     float level_in;
  60
  61     int order;
  62     int filter_count;
  63     int first_order;
  64     int ap_filter_count;
  65     int nb_splits;
  66     float *splits;
  67
  68     CrossoverChannel *xover;
  69
  70     AVFrame *input_frame;
  71     AVFrame *frames[MAX_BANDS];
  72
  73     int (*filter_channels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  74
  75     AVFloatDSPContext *fdsp;
  76 } AudioCrossoverContext;
  77
  78 #define OFFSET(x) offsetof(AudioCrossoverContext, x)
  79 #define AF AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
  80
  81 static const AVOption acrossover_options[] = {
  82     { "split", "set split frequencies", OFFSET(splits_str), AV_OPT_TYPE_STRING, {.str="500"}, 0, 0, AF },
  83     { "order", "set order",             OFFSET(order_opt),  AV_OPT_TYPE_INT,    {.i64=1},     0, 9, AF, "m" },
  84     { "2nd",   "2nd order",             0,                  AV_OPT_TYPE_CONST,  {.i64=0},     0, 0, AF, "m" },
  85     { "4th",   "4th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=1},     0, 0, AF, "m" },
  86     { "6th",   "6th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=2},     0, 0, AF, "m" },
  87     { "8th",   "8th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=3},     0, 0, AF, "m" },
  88     { "10th",  "10th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=4},     0, 0, AF, "m" },
  89     { "12th",  "12th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=5},     0, 0, AF, "m" },
  90     { "14th",  "14th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=6},     0, 0, AF, "m" },
  91     { "16th",  "16th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=7},     0, 0, AF, "m" },
  92     { "18th",  "18th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=8},     0, 0, AF, "m" },
  93     { "20th",  "20th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=9},     0, 0, AF, "m" },
  94     { "level", "set input gain",        OFFSET(level_in),   AV_OPT_TYPE_FLOAT,  {.dbl=1},     0, 1, AF },
  95     { NULL }
  96 };
  97
  98 AVFILTER_DEFINE_CLASS(acrossover);
  99
 100 static av_cold int init(AVFilterContext *ctx)
 101 {
 102     AudioCrossoverContext *s = ctx->priv;
 103     char *p, *arg, *saveptr = NULL;
 104     int i, ret = 0;
 105
 106     s->fdsp = avpriv_float_dsp_alloc(0);
 107     if (!s->fdsp)
 108         return AVERROR(ENOMEM);
 109
 110     s->splits = av_calloc(MAX_SPLITS, sizeof(*s->splits));
 111     if (!s->splits)
 112         return AVERROR(ENOMEM);
 113
 114     p = s->splits_str;
 115     for (i = 0; i < MAX_SPLITS; i++) {
 116         float freq;
 117
 118         if (!(arg = av_strtok(p, " |", &saveptr)))
 119             break;
 120
 121         p = NULL;
 122
 123         if (av_sscanf(arg, "%f", &freq) != 1) {
 124             av_log(ctx, AV_LOG_ERROR, "Invalid syntax for frequency[%d].\n", i);
 125             return AVERROR(EINVAL);
 126         }
 127         if (freq <= 0) {
 128             av_log(ctx, AV_LOG_ERROR, "Frequency %f must be positive number.\n", freq);
 129             return AVERROR(EINVAL);
 130         }
 131
 132         if (i > 0 && freq <= s->splits[i-1]) {
 133             av_log(ctx, AV_LOG_ERROR, "Frequency %f must be in increasing order.\n", freq);
 134             return AVERROR(EINVAL);
 135         }
 136
 137         s->splits[i] = freq;
 138     }
 139
 140     s->nb_splits = i;
 141
 142     for (i = 0; i <= s->nb_splits; i++) {
 143         AVFilterPad pad  = { 0 };
 144         char *name;
 145
 146         pad.type = AVMEDIA_TYPE_AUDIO;
 147         name = av_asprintf("out%d", ctx->nb_outputs);
 148         if (!name)
 149             return AVERROR(ENOMEM);
 150         pad.name = name;
 151
 152         if ((ret = ff_insert_outpad(ctx, i, &pad)) < 0) {
 153             av_freep(&pad.name);
 154             return ret;
 155         }
 156     }
 157
 158     return ret;
 159 }
 160
 161 static void set_lp(BiquadContext *b, double fc, double q, double sr)
 162 {
 163     double omega = M_PI * fc / sr;
 164     double cosine = cos(omega);
 165     double alpha = sin(omega) / (2. * q);
 166
 167     double b0 = (1. - cosine) / 2.;
 168     double b1 = 1. - cosine;
 169     double b2 = (1. - cosine) / 2.;
 170     double a0 = 1. + alpha;
 171     double a1 = -2. * cosine;
 172     double a2 = 1. - alpha;
 173
 174     b->b0 =  b0 / a0;
 175     b->b1 =  b1 / a0;
 176     b->b2 =  b2 / a0;
 177     b->a1 = -a1 / a0;
 178     b->a2 = -a2 / a0;
 179 }
 180
 181 static void set_hp(BiquadContext *b, double fc, double q, double sr)
 182 {
 183     double omega = M_PI * fc / sr;
 184     double cosine = cos(omega);
 185     double alpha = sin(omega) / (2. * q);
 186
 187     double b0 = (1. + cosine) / 2.;
 188     double b1 = -1. - cosine;
 189     double b2 = (1. + cosine) / 2.;
 190     double a0 = 1. + alpha;
 191     double a1 = -2. * cosine;
 192     double a2 = 1. - alpha;
 193
 194     b->b0 =  b0 / a0;
 195     b->b1 =  b1 / a0;
 196     b->b2 =  b2 / a0;
 197     b->a1 = -a1 / a0;
 198     b->a2 = -a2 / a0;
 199 }
 200
 201 static void set_ap(BiquadContext *b, double fc, double q, double sr)
 202 {
 203     double omega = M_PI * fc / sr;
 204     double cosine = cos(omega);
 205     double alpha = sin(omega) / (2. * q);
 206
 207     double a0 = 1. + alpha;
 208     double a1 = -2. * cosine;
 209     double a2 = 1. - alpha;
 210     double b0 = a2;
 211     double b1 = a1;
 212     double b2 = a0;
 213
 214     b->b0 =  b0 / a0;
 215     b->b1 =  b1 / a0;
 216     b->b2 =  b2 / a0;
 217     b->a1 = -a1 / a0;
 218     b->a2 = -a2 / a0;
 219 }
 220
 221 static void set_ap1(BiquadContext *b, double fc, double sr)
 222 {
 223     double omega = M_PI * fc / sr;
 224
 225     b->a1 = exp(-omega);
 226     b->a2 = 0.;
 227     b->b0 = -b->a1;
 228     b->b1 = 1.;
 229     b->b2 = 0.;
 230 }
 231
 232 static void calc_q_factors(int order, double *q)
 233 {
 234     double n = order / 2.;
 235
 236     for (int i = 0; i < n / 2; i++)
 237         q[i] = 1. / (-2. * cos(M_PI * (2. * (i + 1) + n - 1.) / (2. * n)));
 238 }
 239
 240 static int query_formats(AVFilterContext *ctx)
 241 {
 242     AVFilterFormats *formats;
 243     AVFilterChannelLayouts *layouts;
 244     static const enum AVSampleFormat sample_fmts[] = {
 245         AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_DBLP,
 246         AV_SAMPLE_FMT_NONE
 247     };
 248     int ret;
 249
 250     layouts = ff_all_channel_counts();
 251     if (!layouts)
 252         return AVERROR(ENOMEM);
 253     ret = ff_set_common_channel_layouts(ctx, layouts);
 254     if (ret < 0)
 255         return ret;
 256
 257     formats = ff_make_format_list(sample_fmts);
 258     if (!formats)
 259         return AVERROR(ENOMEM);
 260     ret = ff_set_common_formats(ctx, formats);
 261     if (ret < 0)
 262         return ret;
 263
 264     formats = ff_all_samplerates();
 265     if (!formats)
 266         return AVERROR(ENOMEM);
 267     return ff_set_common_samplerates(ctx, formats);
 268 }
 269
 270 #define BIQUAD_PROCESS(name, type)                             \
 271 static void biquad_process_## name(BiquadContext *b,           \
 272                                    type *dst, const type *src, \
 273                                    int nb_samples)             \
 274 {                                                              \
 275     const type b0 = b->b0;                                     \
 276     const type b1 = b->b1;                                     \
 277     const type b2 = b->b2;                                     \
 278     const type a1 = b->a1;                                     \
 279     const type a2 = b->a2;                                     \
 280     type z1 = b->z1;                                           \
 281     type z2 = b->z2;                                           \
 282                                                                \
 283     for (int n = 0; n < nb_samples; n++) {                     \
 284         const type in = src[n];                                \
 285         type out;                                              \
 286                                                                \
 287         out = in * b0 + z1;                                    \
 288         z1 = b1 * in + z2 + a1 * out;                          \
 289         z2 = b2 * in + a2 * out;                               \
 290         dst[n] = out;                                          \
 291     }                                                          \
 292                                                                \
 293     b->z1 = z1;                                                \
 294     b->z2 = z2;                                                \
 295 }
 296
 297 BIQUAD_PROCESS(fltp, float)
 298 BIQUAD_PROCESS(dblp, double)
 299
 300 #define XOVER_PROCESS(name, type, one, ff)                                                  \
 301 static int filter_channels_## name(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) \
 302 {                                                                                           \
 303     AudioCrossoverContext *s = ctx->priv;                                                   \
 304     AVFrame *in = s->input_frame;                                                           \
 305     AVFrame **frames = s->frames;                                                           \
 306     const int start = (in->channels * jobnr) / nb_jobs;                                     \
 307     const int end = (in->channels * (jobnr+1)) / nb_jobs;                                   \
 308     const int nb_samples = in->nb_samples;                                                  \
 309                                                                                             \
 310     for (int ch = start; ch < end; ch++) {                                                  \
 311         const type *src = (const type *)in->extended_data[ch];                              \
 312         CrossoverChannel *xover = &s->xover[ch];                                            \
 313                                                                                             \
 314         s->fdsp->vector_## ff ##mul_scalar((type *)frames[0]->extended_data[ch], src,       \
 315                                     s->level_in, nb_samples);                               \
 316         emms_c();                                                                           \
 317                                                                                             \
 318         for (int band = 0; band < ctx->nb_outputs; band++) {                                \
 319             for (int f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) {       \
 320                 const type *prv = (const type *)frames[band]->extended_data[ch];            \
 321                 type *dst = (type *)frames[band + 1]->extended_data[ch];                    \
 322                 const type *hsrc = f == 0 ? prv : dst;                                      \
 323                 BiquadContext *hp = &xover->hp[band][f];                                    \
 324                                                                                             \
 325                 biquad_process_## name(hp, dst, hsrc, nb_samples);                          \
 326             }                                                                               \
 327                                                                                             \
 328             for (int f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) {       \
 329                 type *dst = (type *)frames[band]->extended_data[ch];                        \
 330                 const type *lsrc = dst;                                                     \
 331                 BiquadContext *lp = &xover->lp[band][f];                                    \
 332                                                                                             \
 333                 biquad_process_## name(lp, dst, lsrc, nb_samples);                          \
 334             }                                                                               \
 335                                                                                             \
 336             for (int aband = band + 1; aband + 1 < ctx->nb_outputs; aband++) {              \
 337                 if (s->first_order) {                                                       \
 338                     const type *asrc = (const type *)frames[band]->extended_data[ch];       \
 339                     type *dst = (type *)frames[band]->extended_data[ch];                    \
 340                     BiquadContext *ap = &xover->ap[band][aband][0];                         \
 341                                                                                             \
 342                     biquad_process_## name(ap, dst, asrc, nb_samples);                      \
 343                 }                                                                           \
 344                                                                                             \
 345                 for (int f = s->first_order; f < s->ap_filter_count; f++) {                 \
 346                     const type *asrc = (const type *)frames[band]->extended_data[ch];       \
 347                     type *dst = (type *)frames[band]->extended_data[ch];                    \
 348                     BiquadContext *ap = &xover->ap[band][aband][f];                         \
 349                                                                                             \
 350                     biquad_process_## name(ap, dst, asrc, nb_samples);                      \
 351                 }                                                                           \
 352             }                                                                               \
 353         }                                                                                   \
 354                                                                                             \
 355         for (int band = 0; band < ctx->nb_outputs && s->first_order; band++) {              \
 356             if (band & 1) {                                                                 \
 357                 type *dst = (type *)frames[band]->extended_data[ch];                        \
 358                                                                                             \
 359                 for (int n = 0; n < nb_samples; n++)                                        \
 360                     dst[n] *= -one;                                                         \
 361             }                                                                               \
 362         }                                                                                   \
 363     }                                                                                       \
 364                                                                                             \
 365     return 0;                                                                               \
 366 }
 367
 368 XOVER_PROCESS(fltp, float, 1.f, f)
 369 XOVER_PROCESS(dblp, double, 1.0, d)
 370
 371 static int config_input(AVFilterLink *inlink)
 372 {
 373     AVFilterContext *ctx = inlink->dst;
 374     AudioCrossoverContext *s = ctx->priv;
 375     int sample_rate = inlink->sample_rate;
 376     double q[16];
 377
 378     s->xover = av_calloc(inlink->channels, sizeof(*s->xover));
 379     if (!s->xover)
 380         return AVERROR(ENOMEM);
 381
 382     s->order = (s->order_opt + 1) * 2;
 383     s->filter_count = s->order / 2;
 384     s->first_order = s->filter_count & 1;
 385     s->ap_filter_count = s->filter_count / 2 + s->first_order;
 386     calc_q_factors(s->order, q);
 387
 388     for (int ch = 0; ch < inlink->channels; ch++) {
 389         for (int band = 0; band <= s->nb_splits; band++) {
 390             if (s->first_order) {
 391                 set_lp(&s->xover[ch].lp[band][0], s->splits[band], 0.5, sample_rate);
 392                 set_hp(&s->xover[ch].hp[band][0], s->splits[band], 0.5, sample_rate);
 393             }
 394
 395             for (int n = s->first_order; n < s->filter_count; n++) {
 396                 const int idx = s->filter_count / 2 - ((n + s->first_order) / 2 - s->first_order) - 1;
 397
 398                 set_lp(&s->xover[ch].lp[band][n], s->splits[band], q[idx], sample_rate);
 399                 set_hp(&s->xover[ch].hp[band][n], s->splits[band], q[idx], sample_rate);
 400             }
 401
 402             for (int x = 0; x <= s->nb_splits && s->first_order; x++)
 403                 set_ap1(&s->xover[ch].ap[x][band][0], s->splits[band], sample_rate);
 404
 405             for (int n = s->first_order; n < s->ap_filter_count; n++) {
 406                 const int idx = (s->filter_count / 2 - ((n * 2 + s->first_order) / 2 - s->first_order) - 1);
 407
 408                 for (int x = 0; x <= s->nb_splits; x++)
 409                     set_ap(&s->xover[ch].ap[x][band][n], s->splits[band], q[idx], sample_rate);
 410             }
 411         }
 412     }
 413
 414     switch (inlink->format) {
 415     case AV_SAMPLE_FMT_FLTP: s->filter_channels = filter_channels_fltp; break;
 416     case AV_SAMPLE_FMT_DBLP: s->filter_channels = filter_channels_dblp; break;
 417     }
 418
 419     return 0;
 420 }
 421
 422 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 423 {
 424     AVFilterContext *ctx = inlink->dst;
 425     AudioCrossoverContext *s = ctx->priv;
 426     AVFrame **frames = s->frames;
 427     int i, ret = 0;
 428
 429     for (i = 0; i < ctx->nb_outputs; i++) {
 430         frames[i] = ff_get_audio_buffer(ctx->outputs[i], in->nb_samples);
 431
 432         if (!frames[i]) {
 433             ret = AVERROR(ENOMEM);
 434             break;
 435         }
 436
 437         frames[i]->pts = in->pts;
 438     }
 439
 440     if (ret < 0)
 441         goto fail;
 442
 443     s->input_frame = in;
 444     ctx->internal->execute(ctx, s->filter_channels, NULL, NULL, FFMIN(inlink->channels,
 445                                                                       ff_filter_get_nb_threads(ctx)));
 446
 447     for (i = 0; i < ctx->nb_outputs; i++) {
 448         ret = ff_filter_frame(ctx->outputs[i], frames[i]);
 449         frames[i] = NULL;
 450         if (ret < 0)
 451             break;
 452     }
 453
 454 fail:
 455     for (i = 0; i < ctx->nb_outputs; i++)
 456         av_frame_free(&frames[i]);
 457     av_frame_free(&in);
 458     s->input_frame = NULL;
 459
 460     return ret;
 461 }
 462
 463 static av_cold void uninit(AVFilterContext *ctx)
 464 {
 465     AudioCrossoverContext *s = ctx->priv;
 466     int i;
 467
 468     av_freep(&s->fdsp);
 469     av_freep(&s->splits);
 470     av_freep(&s->xover);
 471
 472     for (i = 0; i < ctx->nb_outputs; i++)
 473         av_freep(&ctx->output_pads[i].name);
 474 }
 475
 476 static const AVFilterPad inputs[] = {
 477     {
 478         .name         = "default",
 479         .type         = AVMEDIA_TYPE_AUDIO,
 480         .filter_frame = filter_frame,
 481         .config_props = config_input,
 482     },
 483     { NULL }
 484 };
 485
 486 AVFilter ff_af_acrossover = {
 487     .name           = "acrossover",
 488     .description    = NULL_IF_CONFIG_SMALL("Split audio into per-bands streams."),
 489     .priv_size      = sizeof(AudioCrossoverContext),
 490     .priv_class     = &acrossover_class,
 491     .init           = init,
 492     .uninit         = uninit,
 493     .query_formats  = query_formats,
 494     .inputs         = inputs,
 495     .outputs        = NULL,
 496     .flags          = AVFILTER_FLAG_DYNAMIC_OUTPUTS |
 497                       AVFILTER_FLAG_SLICE_THREADS,
 498 };