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