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   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 BiquadCoeffs {
  43     double b0, b1, b2;
  44     double a1, a2;
  45 } BiquadCoeffs;
  46
  47 typedef struct BiquadContext {
  48     double z1, z2;
  49 } BiquadContext;
  50
  51 typedef struct CrossoverChannel {
  52     BiquadContext lp[MAX_BANDS][20];
  53     BiquadContext hp[MAX_BANDS][20];
  54     BiquadContext ap[MAX_BANDS][MAX_BANDS][20];
  55 } CrossoverChannel;
  56
  57 typedef struct AudioCrossoverContext {
  58     const AVClass *class;
  59
  60     char *splits_str;
  61     int order_opt;
  62     float level_in;
  63
  64     int order;
  65     int filter_count;
  66     int first_order;
  67     int ap_filter_count;
  68     int nb_splits;
  69     float *splits;
  70
  71     BiquadCoeffs lp[MAX_BANDS][20];
  72     BiquadCoeffs hp[MAX_BANDS][20];
  73     BiquadCoeffs ap[MAX_BANDS][20];
  74
  75     CrossoverChannel *xover;
  76
  77     AVFrame *input_frame;
  78     AVFrame *frames[MAX_BANDS];
  79
  80     int (*filter_channels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  81
  82     AVFloatDSPContext *fdsp;
  83 } AudioCrossoverContext;
  84
  85 #define OFFSET(x) offsetof(AudioCrossoverContext, x)
  86 #define AF AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
  87
  88 static const AVOption acrossover_options[] = {
  89     { "split", "set split frequencies", OFFSET(splits_str), AV_OPT_TYPE_STRING, {.str="500"}, 0, 0, AF },
  90     { "order", "set order",             OFFSET(order_opt),  AV_OPT_TYPE_INT,    {.i64=1},     0, 9, AF, "m" },
  91     { "2nd",   "2nd order",             0,                  AV_OPT_TYPE_CONST,  {.i64=0},     0, 0, AF, "m" },
  92     { "4th",   "4th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=1},     0, 0, AF, "m" },
  93     { "6th",   "6th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=2},     0, 0, AF, "m" },
  94     { "8th",   "8th order",             0,                  AV_OPT_TYPE_CONST,  {.i64=3},     0, 0, AF, "m" },
  95     { "10th",  "10th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=4},     0, 0, AF, "m" },
  96     { "12th",  "12th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=5},     0, 0, AF, "m" },
  97     { "14th",  "14th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=6},     0, 0, AF, "m" },
  98     { "16th",  "16th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=7},     0, 0, AF, "m" },
  99     { "18th",  "18th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=8},     0, 0, AF, "m" },
 100     { "20th",  "20th order",            0,                  AV_OPT_TYPE_CONST,  {.i64=9},     0, 0, AF, "m" },
 101     { "level", "set input gain",        OFFSET(level_in),   AV_OPT_TYPE_FLOAT,  {.dbl=1},     0, 1, AF },
 102     { NULL }
 103 };
 104
 105 AVFILTER_DEFINE_CLASS(acrossover);
 106
 107 static av_cold int init(AVFilterContext *ctx)
 108 {
 109     AudioCrossoverContext *s = ctx->priv;
 110     char *p, *arg, *saveptr = NULL;
 111     int i, ret = 0;
 112
 113     s->fdsp = avpriv_float_dsp_alloc(0);
 114     if (!s->fdsp)
 115         return AVERROR(ENOMEM);
 116
 117     s->splits = av_calloc(MAX_SPLITS, sizeof(*s->splits));
 118     if (!s->splits)
 119         return AVERROR(ENOMEM);
 120
 121     p = s->splits_str;
 122     for (i = 0; i < MAX_SPLITS; i++) {
 123         float freq;
 124
 125         if (!(arg = av_strtok(p, " |", &saveptr)))
 126             break;
 127
 128         p = NULL;
 129
 130         if (av_sscanf(arg, "%f", &freq) != 1) {
 131             av_log(ctx, AV_LOG_ERROR, "Invalid syntax for frequency[%d].\n", i);
 132             return AVERROR(EINVAL);
 133         }
 134         if (freq <= 0) {
 135             av_log(ctx, AV_LOG_ERROR, "Frequency %f must be positive number.\n", freq);
 136             return AVERROR(EINVAL);
 137         }
 138
 139         if (i > 0 && freq <= s->splits[i-1]) {
 140             av_log(ctx, AV_LOG_ERROR, "Frequency %f must be in increasing order.\n", freq);
 141             return AVERROR(EINVAL);
 142         }
 143
 144         s->splits[i] = freq;
 145     }
 146
 147     s->nb_splits = i;
 148
 149     for (i = 0; i <= s->nb_splits; i++) {
 150         AVFilterPad pad  = { 0 };
 151         char *name;
 152
 153         pad.type = AVMEDIA_TYPE_AUDIO;
 154         name = av_asprintf("out%d", ctx->nb_outputs);
 155         if (!name)
 156             return AVERROR(ENOMEM);
 157         pad.name = name;
 158
 159         if ((ret = ff_insert_outpad(ctx, i, &pad)) < 0) {
 160             av_freep(&pad.name);
 161             return ret;
 162         }
 163     }
 164
 165     return ret;
 166 }
 167
 168 static void set_lp(BiquadCoeffs *b, double fc, double q, double sr)
 169 {
 170     double omega = 2. * M_PI * fc / sr;
 171     double cosine = cos(omega);
 172     double alpha = sin(omega) / (2. * q);
 173
 174     double b0 = (1. - cosine) / 2.;
 175     double b1 = 1. - cosine;
 176     double b2 = (1. - cosine) / 2.;
 177     double a0 = 1. + alpha;
 178     double a1 = -2. * cosine;
 179     double a2 = 1. - alpha;
 180
 181     b->b0 =  b0 / a0;
 182     b->b1 =  b1 / a0;
 183     b->b2 =  b2 / a0;
 184     b->a1 = -a1 / a0;
 185     b->a2 = -a2 / a0;
 186 }
 187
 188 static void set_hp(BiquadCoeffs *b, double fc, double q, double sr)
 189 {
 190     double omega = 2. * M_PI * fc / sr;
 191     double cosine = cos(omega);
 192     double alpha = sin(omega) / (2. * q);
 193
 194     double b0 = (1. + cosine) / 2.;
 195     double b1 = -1. - cosine;
 196     double b2 = (1. + cosine) / 2.;
 197     double a0 = 1. + alpha;
 198     double a1 = -2. * cosine;
 199     double a2 = 1. - alpha;
 200
 201     b->b0 =  b0 / a0;
 202     b->b1 =  b1 / a0;
 203     b->b2 =  b2 / a0;
 204     b->a1 = -a1 / a0;
 205     b->a2 = -a2 / a0;
 206 }
 207
 208 static void set_ap(BiquadCoeffs *b, double fc, double q, double sr)
 209 {
 210     double omega = 2. * M_PI * fc / sr;
 211     double cosine = cos(omega);
 212     double alpha = sin(omega) / (2. * q);
 213
 214     double a0 = 1. + alpha;
 215     double a1 = -2. * cosine;
 216     double a2 = 1. - alpha;
 217     double b0 = a2;
 218     double b1 = a1;
 219     double b2 = a0;
 220
 221     b->b0 =  b0 / a0;
 222     b->b1 =  b1 / a0;
 223     b->b2 =  b2 / a0;
 224     b->a1 = -a1 / a0;
 225     b->a2 = -a2 / a0;
 226 }
 227
 228 static void set_ap1(BiquadCoeffs *b, double fc, double sr)
 229 {
 230     double omega = 2. * M_PI * fc / sr;
 231
 232     b->a1 = exp(-omega);
 233     b->a2 = 0.;
 234     b->b0 = -b->a1;
 235     b->b1 = 1.;
 236     b->b2 = 0.;
 237 }
 238
 239 static void calc_q_factors(int order, double *q)
 240 {
 241     double n = order / 2.;
 242
 243     for (int i = 0; i < n / 2; i++)
 244         q[i] = 1. / (-2. * cos(M_PI * (2. * (i + 1) + n - 1.) / (2. * n)));
 245 }
 246
 247 static int query_formats(AVFilterContext *ctx)
 248 {
 249     AVFilterFormats *formats;
 250     AVFilterChannelLayouts *layouts;
 251     static const enum AVSampleFormat sample_fmts[] = {
 252         AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_DBLP,
 253         AV_SAMPLE_FMT_NONE
 254     };
 255     int ret;
 256
 257     layouts = ff_all_channel_counts();
 258     if (!layouts)
 259         return AVERROR(ENOMEM);
 260     ret = ff_set_common_channel_layouts(ctx, layouts);
 261     if (ret < 0)
 262         return ret;
 263
 264     formats = ff_make_format_list(sample_fmts);
 265     if (!formats)
 266         return AVERROR(ENOMEM);
 267     ret = ff_set_common_formats(ctx, formats);
 268     if (ret < 0)
 269         return ret;
 270
 271     formats = ff_all_samplerates();
 272     if (!formats)
 273         return AVERROR(ENOMEM);
 274     return ff_set_common_samplerates(ctx, formats);
 275 }
 276
 277 #define BIQUAD_PROCESS(name, type)                             \
 278 static void biquad_process_## name(const BiquadCoeffs *const c,\
 279                                    BiquadContext *b,           \
 280                                    type *dst, const type *src, \
 281                                    int nb_samples)             \
 282 {                                                              \
 283     const type b0 = c->b0;                                     \
 284     const type b1 = c->b1;                                     \
 285     const type b2 = c->b2;                                     \
 286     const type a1 = c->a1;                                     \
 287     const type a2 = c->a2;                                     \
 288     type z1 = b->z1;                                           \
 289     type z2 = b->z2;                                           \
 290                                                                \
 291     for (int n = 0; n + 1 < nb_samples; n++) {                 \
 292         type in = src[n];                                      \
 293         type out;                                              \
 294                                                                \
 295         out = in * b0 + z1;                                    \
 296         z1 = b1 * in + z2 + a1 * out;                          \
 297         z2 = b2 * in + a2 * out;                               \
 298         dst[n] = out;                                          \
 299                                                                \
 300         n++;                                                   \
 301         in = src[n];                                           \
 302         out = in * b0 + z1;                                    \
 303         z1 = b1 * in + z2 + a1 * out;                          \
 304         z2 = b2 * in + a2 * out;                               \
 305         dst[n] = out;                                          \
 306     }                                                          \
 307                                                                \
 308     if (nb_samples & 1) {                                      \
 309         const int n = nb_samples - 1;                          \
 310         const type in = src[n];                                \
 311         type out;                                              \
 312                                                                \
 313         out = in * b0 + z1;                                    \
 314         z1 = b1 * in + z2 + a1 * out;                          \
 315         z2 = b2 * in + a2 * out;                               \
 316         dst[n] = out;                                          \
 317     }                                                          \
 318                                                                \
 319     b->z1 = z1;                                                \
 320     b->z2 = z2;                                                \
 321 }
 322
 323 BIQUAD_PROCESS(fltp, float)
 324 BIQUAD_PROCESS(dblp, double)
 325
 326 #define XOVER_PROCESS(name, type, one, ff)                                                  \
 327 static int filter_channels_## name(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) \
 328 {                                                                                           \
 329     AudioCrossoverContext *s = ctx->priv;                                                   \
 330     AVFrame *in = s->input_frame;                                                           \
 331     AVFrame **frames = s->frames;                                                           \
 332     const int start = (in->channels * jobnr) / nb_jobs;                                     \
 333     const int end = (in->channels * (jobnr+1)) / nb_jobs;                                   \
 334     const int nb_samples = in->nb_samples;                                                  \
 335                                                                                             \
 336     for (int ch = start; ch < end; ch++) {                                                  \
 337         const type *src = (const type *)in->extended_data[ch];                              \
 338         CrossoverChannel *xover = &s->xover[ch];                                            \
 339                                                                                             \
 340         s->fdsp->vector_## ff ##mul_scalar((type *)frames[0]->extended_data[ch], src,       \
 341                                     s->level_in, FFALIGN(nb_samples, sizeof(type)));        \
 342                                                                                             \
 343         for (int band = 0; band < ctx->nb_outputs; band++) {                                \
 344             for (int f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) {       \
 345                 const type *prv = (const type *)frames[band]->extended_data[ch];            \
 346                 type *dst = (type *)frames[band + 1]->extended_data[ch];                    \
 347                 const type *hsrc = f == 0 ? prv : dst;                                      \
 348                 BiquadContext *hp = &xover->hp[band][f];                                    \
 349                 BiquadCoeffs *hpc = &s->hp[band][f];                                        \
 350                                                                                             \
 351                 biquad_process_## name(hpc, hp, dst, hsrc, nb_samples);                     \
 352             }                                                                               \
 353                                                                                             \
 354             for (int f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) {       \
 355                 type *dst = (type *)frames[band]->extended_data[ch];                        \
 356                 const type *lsrc = dst;                                                     \
 357                 BiquadContext *lp = &xover->lp[band][f];                                    \
 358                 BiquadCoeffs *lpc = &s->lp[band][f];                                        \
 359                                                                                             \
 360                 biquad_process_## name(lpc, lp, dst, lsrc, nb_samples);                     \
 361             }                                                                               \
 362                                                                                             \
 363             for (int aband = band + 1; aband + 1 < ctx->nb_outputs; aband++) {              \
 364                 if (s->first_order) {                                                       \
 365                     const type *asrc = (const type *)frames[band]->extended_data[ch];       \
 366                     type *dst = (type *)frames[band]->extended_data[ch];                    \
 367                     BiquadContext *ap = &xover->ap[band][aband][0];                         \
 368                     BiquadCoeffs *apc = &s->ap[aband][0];                                   \
 369                                                                                             \
 370                     biquad_process_## name(apc, ap, dst, asrc, nb_samples);                 \
 371                 }                                                                           \
 372                                                                                             \
 373                 for (int f = s->first_order; f < s->ap_filter_count; f++) {                 \
 374                     const type *asrc = (const type *)frames[band]->extended_data[ch];       \
 375                     type *dst = (type *)frames[band]->extended_data[ch];                    \
 376                     BiquadContext *ap = &xover->ap[band][aband][f];                         \
 377                     BiquadCoeffs *apc = &s->ap[aband][f];                                   \
 378                                                                                             \
 379                     biquad_process_## name(apc, ap, dst, asrc, nb_samples);                 \
 380                 }                                                                           \
 381             }                                                                               \
 382         }                                                                                   \
 383                                                                                             \
 384         for (int band = 0; band < ctx->nb_outputs && s->first_order; band++) {              \
 385             if (band & 1) {                                                                 \
 386                 type *dst = (type *)frames[band]->extended_data[ch];                        \
 387                 s->fdsp->vector_## ff ##mul_scalar(dst, dst, -one,                          \
 388                                                    FFALIGN(nb_samples, sizeof(type)));      \
 389             }                                                                               \
 390         }                                                                                   \
 391     }                                                                                       \
 392                                                                                             \
 393     return 0;                                                                               \
 394 }
 395
 396 XOVER_PROCESS(fltp, float, 1.f, f)
 397 XOVER_PROCESS(dblp, double, 1.0, d)
 398
 399 static int config_input(AVFilterLink *inlink)
 400 {
 401     AVFilterContext *ctx = inlink->dst;
 402     AudioCrossoverContext *s = ctx->priv;
 403     int sample_rate = inlink->sample_rate;
 404     double q[16];
 405
 406     s->xover = av_calloc(inlink->channels, sizeof(*s->xover));
 407     if (!s->xover)
 408         return AVERROR(ENOMEM);
 409
 410     s->order = (s->order_opt + 1) * 2;
 411     s->filter_count = s->order / 2;
 412     s->first_order = s->filter_count & 1;
 413     s->ap_filter_count = s->filter_count / 2 + s->first_order;
 414     calc_q_factors(s->order, q);
 415
 416     for (int band = 0; band <= s->nb_splits; band++) {
 417         if (s->first_order) {
 418             set_lp(&s->lp[band][0], s->splits[band], 0.5, sample_rate);
 419             set_hp(&s->hp[band][0], s->splits[band], 0.5, sample_rate);
 420         }
 421
 422         for (int n = s->first_order; n < s->filter_count; n++) {
 423             const int idx = s->filter_count / 2 - ((n + s->first_order) / 2 - s->first_order) - 1;
 424
 425             set_lp(&s->lp[band][n], s->splits[band], q[idx], sample_rate);
 426             set_hp(&s->hp[band][n], s->splits[band], q[idx], sample_rate);
 427         }
 428
 429         if (s->first_order)
 430             set_ap1(&s->ap[band][0], s->splits[band], sample_rate);
 431
 432         for (int n = s->first_order; n < s->ap_filter_count; n++) {
 433             const int idx = (s->filter_count / 2 - ((n * 2 + s->first_order) / 2 - s->first_order) - 1);
 434
 435             set_ap(&s->ap[band][n], s->splits[band], q[idx], sample_rate);
 436         }
 437     }
 438
 439     switch (inlink->format) {
 440     case AV_SAMPLE_FMT_FLTP: s->filter_channels = filter_channels_fltp; break;
 441     case AV_SAMPLE_FMT_DBLP: s->filter_channels = filter_channels_dblp; break;
 442     }
 443
 444     return 0;
 445 }
 446
 447 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 448 {
 449     AVFilterContext *ctx = inlink->dst;
 450     AudioCrossoverContext *s = ctx->priv;
 451     AVFrame **frames = s->frames;
 452     int i, ret = 0;
 453
 454     for (i = 0; i < ctx->nb_outputs; i++) {
 455         frames[i] = ff_get_audio_buffer(ctx->outputs[i], in->nb_samples);
 456
 457         if (!frames[i]) {
 458             ret = AVERROR(ENOMEM);
 459             break;
 460         }
 461
 462         frames[i]->pts = in->pts;
 463     }
 464
 465     if (ret < 0)
 466         goto fail;
 467
 468     s->input_frame = in;
 469     ctx->internal->execute(ctx, s->filter_channels, NULL, NULL, FFMIN(inlink->channels,
 470                                                                       ff_filter_get_nb_threads(ctx)));
 471
 472     for (i = 0; i < ctx->nb_outputs; i++) {
 473         ret = ff_filter_frame(ctx->outputs[i], frames[i]);
 474         frames[i] = NULL;
 475         if (ret < 0)
 476             break;
 477     }
 478
 479 fail:
 480     for (i = 0; i < ctx->nb_outputs; i++)
 481         av_frame_free(&frames[i]);
 482     av_frame_free(&in);
 483     s->input_frame = NULL;
 484
 485     return ret;
 486 }
 487
 488 static av_cold void uninit(AVFilterContext *ctx)
 489 {
 490     AudioCrossoverContext *s = ctx->priv;
 491     int i;
 492
 493     av_freep(&s->fdsp);
 494     av_freep(&s->splits);
 495     av_freep(&s->xover);
 496
 497     for (i = 0; i < ctx->nb_outputs; i++)
 498         av_freep(&ctx->output_pads[i].name);
 499 }
 500
 501 static const AVFilterPad inputs[] = {
 502     {
 503         .name         = "default",
 504         .type         = AVMEDIA_TYPE_AUDIO,
 505         .filter_frame = filter_frame,
 506         .config_props = config_input,
 507     },
 508     { NULL }
 509 };
 510
 511 AVFilter ff_af_acrossover = {
 512     .name           = "acrossover",
 513     .description    = NULL_IF_CONFIG_SMALL("Split audio into per-bands streams."),
 514     .priv_size      = sizeof(AudioCrossoverContext),
 515     .priv_class     = &acrossover_class,
 516     .init           = init,
 517     .uninit         = uninit,
 518     .query_formats  = query_formats,
 519     .inputs         = inputs,
 520     .outputs        = NULL,
 521     .flags          = AVFILTER_FLAG_DYNAMIC_OUTPUTS |
 522                       AVFILTER_FLAG_SLICE_THREADS,
 523 };