src/audio_fx.cpp

   1 /* Calf DSP Library
   2  * Reusable audio effect classes - implementation.
   3  *
   4  * Copyright (C) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen and others
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this program; if not, write to the
  18  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  * Boston, MA  02110-1301  USA
  20  */
  21
  22 #include <calf/audio_fx.h>
  23 #include <calf/giface.h>
  24 #include <limits.h>
  25 #include <stdlib.h>
  26 #include <time.h>
  27 #include <math.h>
  28
  29 using namespace calf_plugins;
  30 using namespace dsp;
  31
  32 simple_phaser::simple_phaser(int _max_stages, float *x1vals, float *y1vals)
  33 {
  34     max_stages = _max_stages;
  35     x1 = x1vals;
  36     y1 = y1vals;
  37
  38     set_base_frq(1000);
  39     set_mod_depth(1000);
  40     set_fb(0);
  41     state = 0;
  42     cnt = 0;
  43     stages = 0;
  44     set_stages(_max_stages);
  45 }
  46
  47 void simple_phaser::set_stages(int _stages)
  48 {
  49     if (_stages > stages)
  50     {
  51         assert(_stages <= max_stages);
  52         if (_stages > max_stages)
  53             _stages = max_stages;
  54         for (int i = stages; i < _stages; i++)
  55         {
  56             x1[i] = x1[stages-1];
  57             y1[i] = y1[stages-1];
  58         }
  59     }
  60     stages = _stages;
  61 }
  62
  63 void simple_phaser::reset()
  64 {
  65     cnt = 0;
  66     state = 0;
  67     phase.set(0);
  68     for (int i = 0; i < max_stages; i++)
  69         x1[i] = y1[i] = 0;
  70     control_step();
  71 }
  72
  73 void simple_phaser::control_step()
  74 {
  75     cnt = 0;
  76     int v = phase.get() + 0x40000000;
  77     int sign = v >> 31;
  78     v ^= sign;
  79     // triangle wave, range from 0 to INT_MAX
  80     double vf = (double)((v >> 16) * (1.0 / 16384.0) - 1);
  81
  82     float freq = base_frq * pow(2.0, vf * mod_depth / 1200.0);
  83     freq = dsp::clip<float>(freq, 10.0, 0.49 * sample_rate);
  84     stage1.set_ap_w(freq * (M_PI / 2.0) * odsr);
  85     phase += dphase * 32;
  86     for (int i = 0; i < stages; i++)
  87     {
  88         dsp::sanitize(x1[i]);
  89         dsp::sanitize(y1[i]);
  90     }
  91     dsp::sanitize(state);
  92 }
  93
  94 void simple_phaser::process(float *buf_out, float *buf_in, int nsamples)
  95 {
  96     for (int i=0; i<nsamples; i++) {
  97         cnt++;
  98         if (cnt == 32)
  99             control_step();
 100         float in = *buf_in++;
 101         float fd = in + state * fb;
 102         for (int j = 0; j < stages; j++)
 103             fd = stage1.process_ap(fd, x1[j], y1[j]);
 104         state = fd;
 105
 106         float sdry = in * gs_dry.get();
 107         float swet = fd * gs_wet.get();
 108         *buf_out++ = sdry + swet;
 109     }
 110 }
 111
 112 float simple_phaser::freq_gain(float freq, float sr) const
 113 {
 114     typedef std::complex<double> cfloat;
 115     freq *= 2.0 * M_PI / sr;
 116     cfloat z = 1.0 / exp(cfloat(0.0, freq)); // z^-1
 117
 118     cfloat p = cfloat(1.0);
 119     cfloat stg = stage1.h_z(z);
 120
 121     for (int i = 0; i < stages; i++)
 122         p = p * stg;
 123
 124     p = p / (cfloat(1.0) - cfloat(fb) * p);
 125     return std::abs(cfloat(gs_dry.get_last()) + cfloat(gs_wet.get_last()) * p);
 126 }
 127
 128 ///////////////////////////////////////////////////////////////////////////////////
 129
 130 void biquad_filter_module::calculate_filter(float freq, float q, int mode, float gain)
 131 {
 132     if (mode <= mode_36db_lp) {
 133         order = mode + 1;
 134         left[0].set_lp_rbj(freq, pow(q, 1.0 / order), srate, gain);
 135     } else if ( mode_12db_hp <= mode && mode <= mode_36db_hp ) {
 136         order = mode - mode_12db_hp + 1;
 137         left[0].set_hp_rbj(freq, pow(q, 1.0 / order), srate, gain);
 138     } else if ( mode_6db_bp <= mode && mode <= mode_18db_bp ) {
 139         order = mode - mode_6db_bp + 1;
 140         left[0].set_bp_rbj(freq, pow(q, 1.0 / order), srate, gain);
 141     } else { // mode_6db_br <= mode <= mode_18db_br
 142         order = mode - mode_6db_br + 1;
 143         left[0].set_br_rbj(freq, order * 0.1 * q, srate, gain);
 144     }
 145
 146     right[0].copy_coeffs(left[0]);
 147     for (int i = 1; i < order; i++) {
 148         left[i].copy_coeffs(left[0]);
 149         right[i].copy_coeffs(left[0]);
 150     }
 151 }
 152
 153 void biquad_filter_module::filter_activate()
 154 {
 155     for (int i=0; i < order; i++) {
 156         left[i].reset();
 157         right[i].reset();
 158     }
 159 }
 160
 161 void biquad_filter_module::sanitize()
 162 {
 163     for (int i=0; i < order; i++) {
 164         left[i].sanitize();
 165         right[i].sanitize();
 166     }
 167 }
 168
 169 int biquad_filter_module::process_channel(uint16_t channel_no, const float *in, float *out, uint32_t numsamples, int inmask) {
 170     dsp::biquad_d1 *filter;
 171     switch (channel_no) {
 172     case 0:
 173         filter = left;
 174         break;
 175
 176     case 1:
 177         filter = right;
 178         break;
 179
 180     default:
 181         assert(false);
 182         return 0;
 183     }
 184
 185     if (inmask) {
 186         switch(order) {
 187             case 1:
 188                 for (uint32_t i = 0; i < numsamples; i++)
 189                     out[i] = filter[0].process(in[i]);
 190                 break;
 191             case 2:
 192                 for (uint32_t i = 0; i < numsamples; i++)
 193                     out[i] = filter[1].process(filter[0].process(in[i]));
 194                 break;
 195             case 3:
 196                 for (uint32_t i = 0; i < numsamples; i++)
 197                     out[i] = filter[2].process(filter[1].process(filter[0].process(in[i])));
 198                 break;
 199         }
 200     } else {
 201         if (filter[order - 1].empty())
 202             return 0;
 203         switch(order) {
 204             case 1:
 205                 for (uint32_t i = 0; i < numsamples; i++)
 206                     out[i] = filter[0].process_zeroin();
 207                 break;
 208             case 2:
 209                 if (filter[0].empty())
 210                     for (uint32_t i = 0; i < numsamples; i++)
 211                         out[i] = filter[1].process_zeroin();
 212                 else
 213                     for (uint32_t i = 0; i < numsamples; i++)
 214                         out[i] = filter[1].process(filter[0].process_zeroin());
 215                 break;
 216             case 3:
 217                 if (filter[1].empty())
 218                     for (uint32_t i = 0; i < numsamples; i++)
 219                         out[i] = filter[2].process_zeroin();
 220                 else
 221                     for (uint32_t i = 0; i < numsamples; i++)
 222                         out[i] = filter[2].process(filter[1].process(filter[0].process_zeroin()));
 223                 break;
 224         }
 225     }
 226     for (int i = 0; i < order; i++)
 227         filter[i].sanitize();
 228     return filter[order - 1].empty() ? 0 : inmask;
 229 }
 230
 231 float biquad_filter_module::freq_gain(int subindex, float freq, float srate) const
 232 {
 233     float level = 1.0;
 234     for (int j = 0; j < order; j++)
 235         level *= left[j].freq_gain(freq, srate);
 236     return level;
 237 }
 238
 239 /////////////////////////////////////////////////////////////////////////////////////////////////////////
 240
 241 void reverb::update_times()
 242 {
 243     switch(type)
 244     {
 245     case 0:
 246         tl[0] =  397 << 16, tr[0] =  383 << 16;
 247         tl[1] =  457 << 16, tr[1] =  429 << 16;
 248         tl[2] =  549 << 16, tr[2] =  631 << 16;
 249         tl[3] =  649 << 16, tr[3] =  756 << 16;
 250         tl[4] =  773 << 16, tr[4] =  803 << 16;
 251         tl[5] =  877 << 16, tr[5] =  901 << 16;
 252         break;
 253     case 1:
 254         tl[0] =  697 << 16, tr[0] =  783 << 16;
 255         tl[1] =  957 << 16, tr[1] =  929 << 16;
 256         tl[2] =  649 << 16, tr[2] =  531 << 16;
 257         tl[3] = 1049 << 16, tr[3] = 1177 << 16;
 258         tl[4] =  473 << 16, tr[4] =  501 << 16;
 259         tl[5] =  587 << 16, tr[5] =  681 << 16;
 260         break;
 261     case 2:
 262     default:
 263         tl[0] =  697 << 16, tr[0] =  783 << 16;
 264         tl[1] =  957 << 16, tr[1] =  929 << 16;
 265         tl[2] =  649 << 16, tr[2] =  531 << 16;
 266         tl[3] = 1249 << 16, tr[3] = 1377 << 16;
 267         tl[4] = 1573 << 16, tr[4] = 1671 << 16;
 268         tl[5] = 1877 << 16, tr[5] = 1781 << 16;
 269         break;
 270     case 3:
 271         tl[0] = 1097 << 16, tr[0] = 1087 << 16;
 272         tl[1] = 1057 << 16, tr[1] = 1031 << 16;
 273         tl[2] = 1049 << 16, tr[2] = 1039 << 16;
 274         tl[3] = 1083 << 16, tr[3] = 1055 << 16;
 275         tl[4] = 1075 << 16, tr[4] = 1099 << 16;
 276         tl[5] = 1003 << 16, tr[5] = 1073 << 16;
 277         break;
 278     case 4:
 279         tl[0] =  197 << 16, tr[0] =  133 << 16;
 280         tl[1] =  357 << 16, tr[1] =  229 << 16;
 281         tl[2] =  549 << 16, tr[2] =  431 << 16;
 282         tl[3] =  949 << 16, tr[3] = 1277 << 16;
 283         tl[4] = 1173 << 16, tr[4] = 1671 << 16;
 284         tl[5] = 1477 << 16, tr[5] = 1881 << 16;
 285         break;
 286     case 5:
 287         tl[0] =  197 << 16, tr[0] =  133 << 16;
 288         tl[1] =  257 << 16, tr[1] =  179 << 16;
 289         tl[2] =  549 << 16, tr[2] =  431 << 16;
 290         tl[3] =  619 << 16, tr[3] =  497 << 16;
 291         tl[4] = 1173 << 16, tr[4] = 1371 << 16;
 292         tl[5] = 1577 << 16, tr[5] = 1881 << 16;
 293         break;
 294     }
 295
 296     float fDec=1000 + 2400.f * diffusion;
 297     for (int i = 0 ; i < 6; i++) {
 298         ldec[i]=exp(-float(tl[i] >> 16) / fDec),
 299         rdec[i]=exp(-float(tr[i] >> 16) / fDec);
 300     }
 301 }
 302
 303 void reverb::reset()
 304 {
 305     apL1.reset();apR1.reset();
 306     apL2.reset();apR2.reset();
 307     apL3.reset();apR3.reset();
 308     apL4.reset();apR4.reset();
 309     apL5.reset();apR5.reset();
 310     apL6.reset();apR6.reset();
 311     lp_left.reset();lp_right.reset();
 312     old_left = 0; old_right = 0;
 313 }
 314
 315 void reverb::process(float &left, float &right)
 316 {
 317     unsigned int ipart = phase.ipart();
 318
 319     // the interpolated LFO might be an overkill here
 320     int lfo = phase.lerp_by_fract_int<int, 14, int>(sine.data[ipart], sine.data[ipart+1]) >> 2;
 321     phase += dphase;
 322
 323     left += old_right;
 324     left = apL1.process_allpass_comb_lerp16(left, tl[0] - 45*lfo, ldec[0]);
 325     left = apL2.process_allpass_comb_lerp16(left, tl[1] + 47*lfo, ldec[1]);
 326     float out_left = left;
 327     left = apL3.process_allpass_comb_lerp16(left, tl[2] + 54*lfo, ldec[2]);
 328     left = apL4.process_allpass_comb_lerp16(left, tl[3] - 69*lfo, ldec[3]);
 329     left = apL5.process_allpass_comb_lerp16(left, tl[4] + 69*lfo, ldec[4]);
 330     left = apL6.process_allpass_comb_lerp16(left, tl[5] - 46*lfo, ldec[5]);
 331     old_left = lp_left.process(left * fb);
 332     sanitize(old_left);
 333
 334     right += old_left;
 335     right = apR1.process_allpass_comb_lerp16(right, tr[0] - 45*lfo, rdec[0]);
 336     right = apR2.process_allpass_comb_lerp16(right, tr[1] + 47*lfo, rdec[1]);
 337     float out_right = right;
 338     right = apR3.process_allpass_comb_lerp16(right, tr[2] + 54*lfo, rdec[2]);
 339     right = apR4.process_allpass_comb_lerp16(right, tr[3] - 69*lfo, rdec[3]);
 340     right = apR5.process_allpass_comb_lerp16(right, tr[4] + 69*lfo, rdec[4]);
 341     right = apR6.process_allpass_comb_lerp16(right, tr[5] - 46*lfo, rdec[5]);
 342     old_right = lp_right.process(right * fb);
 343     sanitize(old_right);
 344
 345     left = out_left, right = out_right;
 346 }
 347
 348 /// Distortion Module by Tom Szilagyi
 349 ///
 350 /// This module provides a blendable saturation stage
 351 ///////////////////////////////////////////////////////////////////////////////////////////////
 352
 353 tap_distortion::tap_distortion()
 354 {
 355     is_active = false;
 356     srate = 0;
 357     meter = 0.f;
 358     rdrive = rbdr = kpa = kpb = kna = knb = ap = an = imr = kc = srct = sq = pwrq = prev_med = prev_out = 0.f;
 359     drive_old = blend_old = -1.f;
 360     over = 1;
 361 }
 362
 363 void tap_distortion::activate()
 364 {
 365     is_active = true;
 366     set_params(0.f, 0.f);
 367 }
 368 void tap_distortion::deactivate()
 369 {
 370     is_active = false;
 371 }
 372
 373 void tap_distortion::set_params(float blend, float drive)
 374 {
 375     // set distortion coeffs
 376     if ((drive_old != drive) || (blend_old != blend)) {
 377         rdrive = 12.0f / drive;
 378         rbdr = rdrive / (10.5f - blend) * 780.0f / 33.0f;
 379         kpa = D(2.0f * (rdrive*rdrive) - 1.0f) + 1.0f;
 380         kpb = (2.0f - kpa) / 2.0f;
 381         ap = ((rdrive*rdrive) - kpa + 1.0f) / 2.0f;
 382         kc = kpa / D(2.0f * D(2.0f * (rdrive*rdrive) - 1.0f) - 2.0f * rdrive*rdrive);
 383
 384         srct = (0.1f * srate) / (0.1f * srate + 1.0f);
 385         sq = kc*kc + 1.0f;
 386         knb = -1.0f * rbdr / D(sq);
 387         kna = 2.0f * kc * rbdr / D(sq);
 388         an = rbdr*rbdr / sq;
 389         imr = 2.0f * knb + D(2.0f * kna + 4.0f * an - 1.0f);
 390         pwrq = 2.0f / (imr + 1.0f);
 391
 392         drive_old = drive;
 393         blend_old = blend;
 394     }
 395 }
 396
 397 void tap_distortion::set_sample_rate(uint32_t sr)
 398 {
 399     srate = sr;
 400     over = srate * 2 > 96000 ? 1 : 2;
 401     resampler.set_params(srate, over, 2);
 402 }
 403
 404 float tap_distortion::process(float in)
 405 {
 406     double *samples = resampler.upsample((double)in);
 407     meter = 0.f;
 408     for (int o = 0; o < over; o++) {
 409         float proc = samples[o];
 410         float med;
 411         if (proc >= 0.0f) {
 412             med = (D(ap + proc * (kpa - proc)) + kpb) * pwrq;
 413         } else {
 414             med = (D(an - proc * (kna + proc)) + knb) * pwrq * -1.0f;
 415         }
 416         proc = srct * (med - prev_med + prev_out);
 417         prev_med = M(med);
 418         prev_out = M(proc);
 419         samples[o] = proc;
 420         meter = std::max(meter, proc);
 421     }
 422     float out = (float)resampler.downsample(samples);
 423     return out;
 424 }
 425
 426 float tap_distortion::get_distortion_level()
 427 {
 428     return meter;
 429 }
 430
 431 ////////////////////////////////////////////////////////////////////////////////
 432
 433 simple_lfo::simple_lfo()
 434 {
 435     is_active       = false;
 436     phase = 0.f;
 437 }
 438
 439 void simple_lfo::activate()
 440 {
 441     is_active = true;
 442     phase = 0.f;
 443 }
 444
 445 void simple_lfo::deactivate()
 446 {
 447     is_active = false;
 448 }
 449
 450 float simple_lfo::get_value()
 451 {
 452     return get_value_from_phase(phase, offset) * amount;
 453 }
 454
 455 float simple_lfo::get_value_from_phase(float ph, float off) const
 456 {
 457     float val = 0.f;
 458     float phs = ph + off;
 459     if (phs >= 1.0)
 460         phs = fmod(phs, 1.f);
 461     switch (mode) {
 462         default:
 463         case 0:
 464             // sine
 465             val = sin((phs * 360.f) * M_PI / 180);
 466             break;
 467         case 1:
 468             // triangle
 469             if(phs > 0.75)
 470                 val = (phs - 0.75) * 4 - 1;
 471             else if(phs > 0.5)
 472                 val = (phs - 0.5) * 4 * -1;
 473             else if(phs > 0.25)
 474                 val = 1 - (phs - 0.25) * 4;
 475             else
 476                 val = phs * 4;
 477             break;
 478         case 2:
 479             // square
 480             val = (phs < 0.5) ? -1 : +1;
 481             break;
 482         case 3:
 483             // saw up
 484                 val = phs * 2.f - 1;
 485             break;
 486         case 4:
 487             // saw down
 488             val = 1 - phs * 2.f;
 489             break;
 490     }
 491     return val;
 492 }
 493
 494 void simple_lfo::advance(uint32_t count)
 495 {
 496     //this function walks from 0.f to 1.f and starts all over again
 497     phase += count * freq * (1.0 / srate);
 498     if (phase >= 1.0)
 499         phase = fmod(phase, 1.f);
 500 }
 501
 502 void simple_lfo::set_phase(float ph)
 503 {
 504     //set the phase from outsinde
 505     phase = fabs(ph);
 506     if (phase >= 1.0)
 507         phase = fmod(phase, 1.f);
 508 }
 509
 510 void simple_lfo::set_params(float f, int m, float o, uint32_t sr, float a)
 511 {
 512     // freq: a value in Hz
 513     // mode: sine=0, triangle=1, square=2, saw_up=3, saw_down=4
 514     // offset: value between 0.f and 1.f to offset the lfo in time
 515     freq = f;
 516     mode = m;
 517     offset = o;
 518     srate = sr;
 519     amount = a;
 520 }
 521 void simple_lfo::set_freq(float f)
 522 {
 523     freq = f;
 524 }
 525 void simple_lfo::set_mode(int m)
 526 {
 527     mode = m;
 528 }
 529 void simple_lfo::set_offset(float o)
 530 {
 531     offset = o;
 532 }
 533 void simple_lfo::set_amount(float a)
 534 {
 535     amount = a;
 536 }
 537 bool simple_lfo::get_graph(float *data, int points, cairo_iface *context, int *mode) const
 538 {
 539     if (!is_active)
 540         return false;
 541     for (int i = 0; i < points; i++) {
 542         float ph = (float)i / (float)points;
 543         data[i] = get_value_from_phase(ph, offset) * amount;
 544     }
 545     return true;
 546 }
 547
 548 bool simple_lfo::get_dot(float &x, float &y, int &size, cairo_iface *context) const
 549 {
 550     if (!is_active)
 551         return false;
 552     float phs = phase + offset;
 553     if (phs >= 1.0)
 554         phs = fmod(phs, 1.f);
 555     x = phase;
 556     y = get_value_from_phase(phase, offset) * amount;
 557     return true;
 558 }
 559
 560
 561 /// Lookahead Limiter by Christian Holschuh and Markus Schmidt
 562
 563 lookahead_limiter::lookahead_limiter() {
 564     is_active = false;
 565     channels = 2;
 566     id = 0;
 567     buffer_size = 0;
 568     overall_buffer_size = 0;
 569     att = 1.f;
 570     att_max = 1.0;
 571     pos = 0;
 572     delta = 0.f;
 573     _delta = 0.f;
 574     peak = 0.f;
 575     over_s = 0;
 576     over_c = 1.f;
 577     attack = 0.005;
 578     use_multi = false;
 579     weight = 1.f;
 580     _sanitize = false;
 581     auto_release = false;
 582     asc_active = false;
 583     nextiter = 0;
 584     nextlen = 0;
 585     asc = 0.f;
 586     asc_c = 0;
 587     asc_pos = -1;
 588     asc_changed = false;
 589     asc_coeff = 1.f;
 590 }
 591 lookahead_limiter::~lookahead_limiter()
 592 {
 593     free(buffer);
 594     free(nextpos);
 595     free(nextdelta);
 596 }
 597
 598 void lookahead_limiter::activate()
 599 {
 600     is_active = true;
 601     pos = 0;
 602
 603 }
 604
 605 void lookahead_limiter::set_multi(bool set) { use_multi = set; }
 606
 607 void lookahead_limiter::deactivate()
 608 {
 609     is_active = false;
 610 }
 611
 612 float lookahead_limiter::get_attenuation()
 613 {
 614     float a = att_max;
 615     att_max = 1.0;
 616     return a;
 617 }
 618
 619 void lookahead_limiter::set_sample_rate(uint32_t sr)
 620 {
 621     srate = sr;
 622     // rebuild buffer
 623     overall_buffer_size = (int)(srate * (100.f / 1000.f) * channels) + channels; // buffer size attack rate multiplied by 2 channels
 624     buffer = (float*) calloc(overall_buffer_size, sizeof(float));
 625     pos = 0;
 626
 627     nextdelta = (float*) calloc(overall_buffer_size, sizeof(float));
 628     nextpos = (int*) malloc(overall_buffer_size * sizeof(int));
 629     memset(nextpos, -1, overall_buffer_size * sizeof(int));
 630
 631     reset();
 632 }
 633
 634 void lookahead_limiter::set_params(float l, float a, float r, float w, bool ar, float arc, bool d)
 635 {
 636     limit = l;
 637     attack = a / 1000.f;
 638     release = r / 1000.f;
 639     auto_release = ar;
 640     asc_coeff = arc;
 641     debug = d;
 642     weight = w;
 643 }
 644
 645 void lookahead_limiter::reset() {
 646     int bs = (int)(srate * attack * channels);
 647     buffer_size = bs - bs % channels; // buffer size attack rate
 648     _sanitize = true;
 649     pos = 0;
 650     nextpos[0] = -1;
 651     nextlen = 0;
 652     nextiter = 0;
 653     delta = 0.f;
 654     att = 1.f;
 655     reset_asc();
 656 }
 657
 658 void lookahead_limiter::reset_asc() {
 659     asc = 0.f;
 660     asc_c = 0;
 661     asc_pos = pos;
 662     asc_changed = true;
 663 }
 664
 665 float lookahead_limiter::get_rdelta(float peak, float _limit, float _att, bool _asc) {
 666
 667     // calc the att for average input to walk to if we use asc (att of average signal)
 668     float _a_att = (limit * weight) / (asc_coeff * asc) * (float)asc_c;
 669
 670     // calc a release delta from this attenuation
 671     float _rdelta = (1.0 - _att) / (srate * release);
 672     if(_asc and auto_release and asc_c > 0 and _a_att > _att) {
 673         // check if releasing to average level of peaks is steeper than
 674         // releasing to 1.f
 675         float _delta = std::max((_a_att - _att) / (srate * release), _rdelta / 10);
 676         if(_delta < _rdelta) {
 677             asc_active = true;
 678             _asc_used = true;
 679             _rdelta = _delta;
 680         }
 681     }
 682     return _rdelta;
 683 }
 684
 685 void lookahead_limiter::process(float &left, float &right, float * multi_buffer)
 686 {
 687     // PROTIP: harming paying customers enough to make them develop a competing
 688     // product may be considered an example of a less than sound business practice.
 689
 690     // fill lookahead buffer
 691     if(_sanitize) {
 692         // if we're sanitizing (zeroing) the buffer on attack time change,
 693         // don't write the samples to the buffer
 694         buffer[pos] = 0.f;
 695         buffer[pos + 1] = 0.f;
 696     } else {
 697         buffer[pos] = left;
 698         buffer[pos + 1] = right;
 699     }
 700
 701     // are we using multiband? get the multiband coefficient or use 1.f
 702     float multi_coeff = (use_multi) ? multi_buffer[pos] : 1.f;
 703
 704     // calc the real limit including weight and multi coeff
 705     float _limit = limit * multi_coeff * weight;
 706
 707     // input peak - impact higher in left or right channel?
 708     peak = fabs(left) > fabs(right) ? fabs(left) : fabs(right);
 709
 710     // add an eventually appearing peak to the asc fake buffer if asc active
 711     if(auto_release and peak > _limit) {
 712         asc += peak;
 713         asc_c ++;
 714     }
 715
 716     if(peak > _limit or multi_coeff < 1.0) {
 717         float _multi_coeff = 1.f;
 718         float _peak;
 719
 720         // calc the attenuation needed to reduce incoming peak
 721         float _att = std::min(_limit / peak, 1.f);
 722         // calc release without any asc to keep all relevant peaks
 723         float _rdelta = get_rdelta(peak, _limit, _att, false);
 724
 725         // calc the delta for walking to incoming peak attenuation
 726         float _delta = (_limit / peak - att) / buffer_size * channels;
 727
 728         if(_delta < delta) {
 729             // is the delta more important than the actual one?
 730             // if so, we can forget about all stored deltas (because they can't
 731             // be more important - we already checked that earlier) and use this
 732             // delta now. and we have to create a release delta in nextpos buffer
 733             nextpos[0] = pos;
 734             nextpos[1] = -1;
 735             nextdelta[0] = _rdelta;
 736             nextlen = 1;
 737             nextiter = 0;
 738             delta = _delta;
 739         } else {
 740             // we have a peak on input its delta is less important than the
 741             // actual delta. But what about the stored deltas we're following?
 742             bool _found = false;
 743             int i = 0;
 744             for(i = nextiter; i < nextiter + nextlen; i++) {
 745                 // walk through our nextpos buffer
 746                 int j = i % buffer_size;
 747                 // calculate a delta for the next stored peak
 748                 // are we using multiband? then get the multi_coeff for the
 749                 // stored position
 750                 _multi_coeff = (use_multi) ? multi_buffer[nextpos[j]] : 1.f;
 751                 // is the left or the right channel on this position more
 752                 // important?
 753                 _peak = fabs(buffer[nextpos[j]]) > fabs(buffer[nextpos[j] + 1]) ? fabs(buffer[nextpos[j]]) : fabs(buffer[nextpos[j] + 1]);
 754                 // calc a delta to use to reach our incoming peak from the
 755                 // stored position
 756                 _delta = (_limit / peak - (limit * _multi_coeff * weight) / _peak) / (((buffer_size - nextpos[j] + pos) % buffer_size) / channels);
 757                 if(_delta < nextdelta[j]) {
 758                     // if the buffered delta is more important than the delta
 759                     // used to reach our peak from the stored position, store
 760                     // the new delta at that position and stop the loop
 761                     nextdelta[j] = _delta;
 762                     _found = true;
 763                     break;
 764                 }
 765             }
 766             if(_found) {
 767                 // there was something more important in the next-buffer.
 768                 // throw away any position and delta after the important
 769                 // position and add a new release delta
 770                 nextlen = i - nextiter + 1;
 771                 nextpos[(nextiter + nextlen) % buffer_size] = pos;
 772                 nextdelta[(nextiter + nextlen) % buffer_size] = _rdelta;
 773                 // set the next following position value to -1 (cleaning up the
 774                 // nextpos buffer)
 775                 nextpos[(nextiter + nextlen + 1) % buffer_size] = -1;
 776                 // and raise the length of our nextpos buffer for keeping the
 777                 // release value
 778                 nextlen ++;
 779             }
 780         }
 781     }
 782
 783     // switch left and right pointers in buffer to output position
 784     left = buffer[(pos + channels) % buffer_size];
 785     right = buffer[(pos + channels + 1) % buffer_size];
 786
 787     // if a peak leaves the buffer, remove it from asc fake buffer
 788     // but only if we're not sanitizing asc buffer
 789     float _peak = fabs(left) > fabs(right) ? fabs(left) : fabs(right);
 790     float _multi_coeff = (use_multi) ? multi_buffer[(pos + channels) % buffer_size] : 1.f;
 791     if(pos == asc_pos and !asc_changed) {
 792         asc_pos = -1;
 793     }
 794     if(auto_release and asc_pos == -1 and _peak > (limit * weight * _multi_coeff)) {
 795         asc -= _peak;
 796         asc_c --;
 797     }
 798
 799     // change the attenuation level
 800     att += delta;
 801
 802     // ...and calculate outpout from it
 803     left *= att;
 804     right *= att;
 805
 806     if((pos + channels) % buffer_size == nextpos[nextiter]) {
 807         // if we reach a buffered position, change the actual delta and erase
 808         // this (the first) element from nextpos and nextdelta buffer
 809         if(auto_release) {
 810             // set delta to asc influenced release delta
 811             delta = get_rdelta(_peak, (limit * weight * _multi_coeff), att);
 812             if(nextlen > 1) {
 813                 // if there are more positions to walk to, calc delta to next
 814                 // position in buffer and compare it to release delta (keep
 815                 // changes between peaks below asc steepness)
 816                 int _nextpos = nextpos[(nextiter + 1) % buffer_size];
 817                 float __peak = fabs(buffer[_nextpos]) > fabs(buffer[_nextpos + 1]) ? fabs(buffer[_nextpos]) : fabs(buffer[_nextpos + 1]);
 818                 float __multi_coeff = (use_multi) ? multi_buffer[_nextpos] : 1.f;
 819                 float __delta = ((limit * __multi_coeff * weight) / __peak - att) / (((buffer_size + _nextpos - ((pos + channels) % buffer_size)) % buffer_size) / channels);
 820                 if(__delta < delta) {
 821                     delta = __delta;
 822                 }
 823             }
 824         } else {
 825             // if no asc set delta from nextdelta buffer and fix the attenuation
 826             delta = nextdelta[nextiter];
 827             att = (limit * weight * _multi_coeff) / _peak;
 828         }
 829         // remove first element from circular nextpos buffer
 830         nextlen -= 1;
 831         nextpos[nextiter] = -1;
 832         nextiter = (nextiter + 1) % buffer_size;
 833     }
 834
 835     if (att > 1.0f) {
 836         // release time seems over, reset attenuation and delta
 837         att = 1.0f;
 838         delta = 0.0f;
 839         nextiter = 0;
 840         nextlen = 0;
 841         nextpos[0] = -1;
 842     }
 843
 844     // main limiting party is over, let's cleanup the puke
 845
 846     if(_sanitize) {
 847         // we're sanitizing? then send 0.f as output
 848         left = 0.f;
 849         right = 0.f;
 850     }
 851
 852     // security personnel pawing your values
 853     if(att <= 0.f) {
 854         // if this happens we're doomed!!
 855         // may happen on manually lowering attack
 856         att = 0.0000000000001;
 857         delta = (1.0f - att) / (srate * release);
 858     }
 859
 860     if(att != 1.f and 1 - att < 0.0000000000001) {
 861         // denormalize att
 862         att = 1.f;
 863     }
 864
 865     if(delta != 0.f and fabs(delta) < 0.00000000000001) {
 866         // denormalize delta
 867         delta = 0.f;
 868     }
 869
 870     // post treatment (denormal, limit)
 871     denormal(&left);
 872     denormal(&right);
 873
 874     // store max attenuation for meter output
 875     att_max = (att < att_max) ? att : att_max;
 876
 877     // step forward in our sample ring buffer
 878     pos = (pos + channels) % buffer_size;
 879
 880     // sanitizing is always done after a full cycle through the lookahead buffer
 881     if(_sanitize and pos == 0) _sanitize = false;
 882
 883     asc_changed = false;
 884 }
 885
 886 bool lookahead_limiter::get_asc() {
 887     if(!asc_active) return false;
 888     asc_active = false;
 889     return true;
 890 }
 891
 892
 893 ////////////////////////////////////////////////////////////////////////////////
 894
 895 transients::transients() {
 896     envelope        = 0.f;
 897     attack          = 0.f;
 898     release         = 0.f;
 899     attack_coef     = 0.f;
 900     release_coef    = 0.f;
 901     att_time        = 0.f;
 902     att_level       = 0.f;
 903     rel_time        = 0.f;
 904     rel_level       = 0.f;
 905     sust_thres      = 1.f;
 906     maxdelta        = 0.f;
 907     new_return      = 1.f;
 908     old_return      = 1.f;
 909     lookahead       = 0;
 910     lookpos         = 0;
 911     channels        = 1;
 912     cnt             = 0;
 913     mix             = 1;
 914     sustain_ended   = false;
 915 }
 916 transients::~transients()
 917 {
 918     free(lookbuf);
 919 }
 920 void transients::set_channels(int ch) {
 921     channels = ch;
 922     lookbuf = (float*) calloc(looksize * channels, sizeof(float));
 923     lookpos = 0;
 924 }
 925 void transients::set_sample_rate(uint32_t sr) {
 926     srate = sr;
 927     attack_coef  = exp(log(0.01) / (0.001 * srate));
 928     release_coef = exp(log(0.01) / (0.2f  * srate));
 929     // due to new calculation in attack, we sometimes get harsh
 930     // gain reduction/boost.
 931     // to prevent "clicks" a maxdelta is set, which allows the signal
 932     // to raise/fall ~6dB/ms.
 933     maxdelta = pow(4, 1.f / (0.001 * srate));
 934     calc_relfac();
 935 }
 936 void transients::set_params(float att_t, float att_l, float rel_t, float rel_l, float sust_th, int look, float mx) {
 937     mix        = mx;
 938     lookahead  = look;
 939     sust_thres = sust_th;
 940     att_time   = att_t;
 941     rel_time   = rel_t;
 942     att_level  = att_l > 0 ? 0.25f * pow(att_l * 8, 2)
 943                           : -0.25f * pow(att_l * 4, 2);
 944     rel_level  = rel_l > 0 ? 0.5f  * pow(rel_l * 8, 2)
 945                           : -0.25f * pow(rel_l * 4, 2);
 946     calc_relfac();
 947 }
 948 void transients::calc_relfac()
 949 {
 950     relfac = pow(0.5f, 1.f / (0.001 * rel_time * srate));
 951 }
 952 void transients::process(float *in) {
 953     // fill lookahead buffer
 954     float s = 0;
 955     for (int i = 0; i < channels; i++) {
 956         lookbuf[lookpos + i] = in[i];
 957         s += fabs(in[i]);
 958     }
 959     s /= channels;
 960
 961     // envelope follower
 962     // this is the real envelope follower curve. It raises as
 963     // fast as the signal is raising and falls much slower
 964     // depending on the sample rate and the ffactor
 965     // (the falling factor)
 966     if(s > envelope)
 967         envelope = attack_coef * (envelope - s) + s;
 968     else
 969         envelope = release_coef * (envelope - s) + s;
 970
 971     // attack follower
 972     // this is a curve which follows the envelope slowly.
 973     // It never can rise above the envelope. It reaches 70.7%
 974     // of the envelope in a certain amount of time set by the user
 975
 976     float attdelta = (envelope - attack)
 977                    * 0.707
 978                    / (srate * att_time * 0.001);
 979     if (sustain_ended == true and envelope / attack - 1 > 0.2f)
 980         sustain_ended = false;
 981     attack += attdelta;
 982
 983     // never raise above envelope
 984     attack = std::min(envelope, attack);
 985
 986     // release follower
 987     // this is a curve which is always above the envelope. It
 988     // starts to fall when the envelope falls beneath the
 989     // sustain threshold
 990
 991     if ((envelope / release) - sust_thres < 0 and sustain_ended == false)
 992         sustain_ended = true;
 993     double reldelta = sustain_ended ? relfac : 1;
 994
 995     // release delta can never raise above 0
 996     release *= reldelta;
 997
 998     // never fall below envelope
 999     release = std::max(envelope, release);
1000
1001     // difference between attack and envelope
1002     float attdiff = attack > 0 ? log(envelope / attack) : 0;
1003
1004     // difference between release and envelope
1005     float reldiff = envelope > 0 ? log(release / envelope) : 0;
1006
1007     // amplification factor from attack and release curve
1008     float ampfactor = attdiff * att_level + reldiff * rel_level;
1009     old_return = new_return;
1010     new_return = 1 + (ampfactor < 0 ? exp(ampfactor) - 1 : ampfactor);
1011     if (new_return / old_return > maxdelta)
1012         new_return = old_return * maxdelta;
1013     if (new_return / old_return < 1 / maxdelta)
1014         new_return = old_return / maxdelta;
1015
1016     int pos = (lookpos + looksize * channels - lookahead * channels) % (looksize * channels);
1017     for (int i = 0; i < channels; i++) {
1018         in[i] = lookbuf[pos + i] * new_return * mix + lookbuf[pos + i] * (mix * -1 + 1);
1019     }
1020
1021     // advance lookpos
1022     lookpos = (lookpos + channels) % (looksize * channels);
1023
1024     cnt += 1;
1025 }
1026
1027
1028 //////////////////////////////////////////////////////////////////
1029
1030 crossover::crossover() {
1031     bands     = -1;
1032     mode      = -1;
1033     redraw_graph = 1;
1034 }
1035 void crossover::set_sample_rate(uint32_t sr) {
1036     srate = sr;
1037 }
1038 void crossover::init(int c, int b, uint32_t sr) {
1039     channels = std::min(8, c);
1040     bands    = std::min(8, b);
1041     srate    = sr;
1042     for(int b = 0; b < bands; b ++) {
1043         // reset frequency settings
1044         freq[b]     = 1.0;
1045         active[b]   = true;
1046         level[b]    = 1.0;
1047         for (int c = 0; c < channels; c ++) {
1048             // reset outputs
1049             out[c][b] = 0.f;
1050         }
1051     }
1052 }
1053 float crossover::set_filter(int b, float f, bool force) {
1054     // keep between neighbour bands
1055     if (b)
1056         f = std::max((float)freq[b-1] * 1.1f, f);
1057     if (b < bands - 2)
1058         f = std::min((float)freq[b+1] * 0.9f, f);
1059     // restrict to 10-20k
1060     f = std::max(10.f, std::min(20000.f, f));
1061     // nothing changed? return
1062     if (freq[b] == f and !force)
1063         return freq[b];
1064     freq[b] = f;
1065     float q;
1066     switch (mode) {
1067         case 0:
1068         default:
1069             q = 0.5;
1070             break;
1071         case 1:
1072             q = 0.7071068123730965;
1073             break;
1074         case 2:
1075             q = 0.54;
1076             break;
1077     }
1078     for (int c = 0; c < channels; c ++) {
1079         if (!c) {
1080             lp[c][b][0].set_lp_rbj(freq[b], q, (float)srate);
1081             hp[c][b][0].set_hp_rbj(freq[b], q, (float)srate);
1082         } else {
1083             lp[c][b][0].copy_coeffs(lp[c-1][b][0]);
1084             hp[c][b][0].copy_coeffs(hp[c-1][b][0]);
1085         }
1086         if (mode > 1) {
1087             if (!c) {
1088                 lp[c][b][1].set_lp_rbj(freq[b], 1.34, (float)srate);
1089                 hp[c][b][1].set_hp_rbj(freq[b], 1.34, (float)srate);
1090             } else {
1091                 lp[c][b][1].copy_coeffs(lp[c-1][b][1]);
1092                 hp[c][b][1].copy_coeffs(hp[c-1][b][1]);
1093             }
1094             lp[c][b][2].copy_coeffs(lp[c][b][0]);
1095             hp[c][b][2].copy_coeffs(hp[c][b][0]);
1096             lp[c][b][3].copy_coeffs(lp[c][b][1]);
1097             hp[c][b][3].copy_coeffs(hp[c][b][1]);
1098         } else {
1099             lp[c][b][1].copy_coeffs(lp[c][b][0]);
1100             hp[c][b][1].copy_coeffs(hp[c][b][0]);
1101         }
1102     }
1103     redraw_graph = std::min(2, redraw_graph + 1);
1104     return freq[b];
1105 }
1106 void crossover::set_mode(int m) {
1107     if(mode == m)
1108         return;
1109     mode = m;
1110     for(int i = 0; i < bands - 1; i ++) {
1111         set_filter(i, freq[i], true);
1112     }
1113     redraw_graph = std::min(2, redraw_graph + 1);
1114 }
1115 void crossover::set_active(int b, bool a) {
1116     if (active[b] == a)
1117         return;
1118     active[b] = a;
1119     redraw_graph = std::min(2, redraw_graph + 1);
1120 }
1121 void crossover::set_level(int b, float l) {
1122     if (level[b] == l)
1123         return;
1124     level[b] = l;
1125     redraw_graph = std::min(2, redraw_graph + 1);
1126 }
1127 void crossover::process(float *data) {
1128     for (int c = 0; c < channels; c++) {
1129         for(int b = 0; b < bands; b ++) {
1130             out[c][b] = data[c];
1131             for (int f = 0; f < get_filter_count(); f++){
1132                 if(b + 1 < bands) {
1133                     out[c][b] = lp[c][b][f].process(out[c][b]);
1134                     lp[c][b][f].sanitize();
1135                 }
1136                 if(b - 1 >= 0) {
1137                     out[c][b] = hp[c][b - 1][f].process(out[c][b]);
1138                     hp[c][b - 1][f].sanitize();
1139                 }
1140             }
1141             out[c][b] *= level[b];
1142         }
1143     }
1144 }
1145 float crossover::get_value(int c, int b) {
1146     return out[c][b];
1147 }
1148 bool crossover::get_graph(int subindex, int phase, float *data, int points, cairo_iface *context, int *mode) const
1149 {
1150     if (subindex >= bands) {
1151         redraw_graph = std::max(0, redraw_graph - 1);
1152         return false;
1153     }
1154     float ret;
1155     double freq;
1156     for (int i = 0; i < points; i++) {
1157         ret = 1.f;
1158         freq = 20.0 * pow (20000.0 / 20.0, i * 1.0 / points);
1159         for(int f = 0; f < get_filter_count(); f ++) {
1160             if(subindex < bands -1)
1161                 ret *= lp[0][subindex][f].freq_gain(freq, (float)srate);
1162             if(subindex > 0)
1163                 ret *= hp[0][subindex - 1][f].freq_gain(freq, (float)srate);
1164         }
1165         ret *= level[subindex];
1166         context->set_source_rgba(0.15, 0.2, 0.0, !active[subindex] ? 0.3 : 0.8);
1167         data[i] = dB_grid(ret);
1168     }
1169     return true;
1170 }
1171 bool crossover::get_layers(int index, int generation, unsigned int &layers) const
1172 {
1173     layers = 0 | (redraw_graph or !generation ? LG_CACHE_GRAPH : 0) | (!generation ? LG_CACHE_GRID : 0);
1174     return redraw_graph or !generation;
1175 }
1176
1177 int crossover::get_filter_count() const
1178 {
1179     switch (mode) {
1180         case 0:
1181         default:
1182             return 1;
1183         case 1:
1184             return 2;
1185         case 2:
1186             return 4;
1187     }
1188 }
1189
1190 //////////////////////////////////////////////////////////////////
1191
1192 bitreduction::bitreduction()
1193 {
1194     coeff        = 1;
1195     morph        = 0;
1196     mode         = 0;
1197     dc           = 0;
1198     sqr          = 0;
1199     aa           = 0;
1200     aa1          = 0;
1201     redraw_graph = true;
1202     bypass       = true;
1203 }
1204 void bitreduction::set_sample_rate(uint32_t sr)
1205 {
1206     srate = sr;
1207 }
1208 void bitreduction::set_params(float b, float mo, bool bp, uint32_t md, float d, float a)
1209 {
1210     morph        = 1 - mo;
1211     bypass       = bp;
1212     dc           = d;
1213     aa           = a;
1214     mode         = md;
1215     coeff        = powf(2.0f, b) - 1;
1216     sqr          = sqrt(coeff / 2);
1217     aa1          = (1.f - aa) / 2.f;
1218     redraw_graph = true;
1219 }
1220 float bitreduction::add_dc(float s, float dc) const
1221 {
1222     return s > 0 ? s *= dc : s /= dc;
1223 }
1224 float bitreduction::remove_dc(float s, float dc) const
1225 {
1226     return s > 0 ? s /= dc : s *= dc;
1227 }
1228 float bitreduction::waveshape(float in) const
1229 {
1230     double y;
1231     double k;
1232
1233     // add dc
1234     in = add_dc(in, dc);
1235
1236     // main rounding calculation depending on mode
1237
1238     // the idea for anti-aliasing:
1239     // you need a function f which brings you to the scale, where you want to round
1240     // and the function f_b (with f(f_b)=id) which brings you back to your original scale.
1241     //
1242     // then you can use the logic below in the following way:
1243     // y = f(in) and k = roundf(y)
1244     // if (y > k + aa1)
1245     //      k = f_b(k) + ( f_b(k+1) - f_b(k) ) *0.5 * (sin(x - PI/2) + 1)
1246     // if (y < k + aa1)
1247     //      k = f_b(k) - ( f_b(k+1) - f_b(k) ) *0.5 * (sin(x - PI/2) + 1)
1248     //
1249     // whereas x = (fabs(f(in) - k) - aa1) * PI / aa
1250     // for both cases.
1251
1252     switch (mode) {
1253         case 0:
1254         default:
1255             // linear
1256             y = (in) * coeff;
1257             k = roundf(y);
1258             if (k - aa1 <= y and y <= k + aa1) {
1259                 k /= coeff;
1260             } else if (y > k + aa1) {
1261                 k = k / coeff + ((k + 1) / coeff - k / coeff) * 0.5 * (sin(M_PI * (fabs(y - k) - aa1) / aa - M_PI_2) + 1);
1262             } else {
1263                 k = k / coeff - (k / coeff - (k - 1) / coeff) * 0.5 * (sin(M_PI * (fabs(y - k) - aa1) / aa - M_PI_2) + 1);
1264             }
1265             break;
1266         case 1:
1267             // logarithmic
1268             y = sqr * log(fabs(in)) + sqr * sqr;
1269             k = roundf(y);
1270             if(!in) {
1271                 k = 0;
1272             } else if (k - aa1 <= y and y <= k + aa1) {
1273                 k = in / fabs(in) * exp(k / sqr - sqr);
1274             } else if (y > k + aa1) {
1275                 k = in / fabs(in) * (exp(k / sqr - sqr) + (exp((k + 1) / sqr - sqr) - exp(k / sqr - sqr)) * 0.5 * (sin((fabs(y - k) - aa1) / aa * M_PI - M_PI_2) + 1));
1276             } else {
1277                 k = in / fabs(in) * (exp(k / sqr - sqr) - (exp(k / sqr - sqr) - exp((k - 1) / sqr - sqr)) * 0.5 * (sin((fabs(y - k) - aa1) / aa * M_PI - M_PI_2) + 1));
1278             }
1279             break;
1280     }
1281
1282     // morph between dry and wet signal
1283     k += (in - k) * morph;
1284
1285     // remove dc
1286     k = remove_dc(k, dc);
1287
1288     return k;
1289 }
1290 float bitreduction::process(float in)
1291 {
1292     return waveshape(in);
1293 }
1294
1295 bool bitreduction::get_layers(int index, int generation, unsigned int &layers) const
1296 {
1297     layers = redraw_graph or !generation ? LG_CACHE_GRAPH | LG_CACHE_GRID : 0;
1298     return redraw_graph or !generation;
1299 }
1300 bool bitreduction::get_graph(int subindex, int phase, float *data, int points, cairo_iface *context, int *mode) const
1301 {
1302     if (subindex >= 2) {
1303         redraw_graph = false;
1304         return false;
1305     }
1306     for (int i = 0; i < points; i++) {
1307          data[i] = sin(((float)i / (float)points * 360.) * M_PI / 180.);
1308         if (subindex and !bypass)
1309             data[i] = waveshape(data[i]);
1310         else {
1311             context->set_line_width(1);
1312             context->set_source_rgba(0.15, 0.2, 0.0, 0.15);
1313         }
1314     }
1315     return true;
1316 }
1317 bool bitreduction::get_gridline(int subindex, int phase, float &pos, bool &vertical, std::string &legend, cairo_iface *context) const
1318 {
1319     if (phase or subindex)
1320         return false;
1321     pos = 0;
1322     vertical = false;
1323     return true;
1324 }
1325
1326 //////////////////////////////////////////////////////////////////
1327
1328 resampleN::resampleN()
1329 {
1330     factor  = 2;
1331     srate   = 0;
1332     filters = 2;
1333 }
1334 resampleN::~resampleN()
1335 {
1336     free(tmp);
1337 }
1338 void resampleN::set_params(uint32_t sr, int fctr = 2, int fltrs = 2)
1339 {
1340     srate   = sr;
1341     factor  = std::min(16, std::max(1, fctr));
1342     filters = std::min(4, std::max(1, fltrs));
1343     // set all filters
1344     filter[0][0].set_lp_rbj(std::max(25000., (double)srate / 2), 0.8, (float)srate * factor);
1345     for (int i = 1; i < filters; i++) {
1346         filter[0][i].copy_coeffs(filter[0][0]);
1347         filter[1][i].copy_coeffs(filter[0][0]);
1348     }
1349 }
1350 double *resampleN::upsample(double sample)
1351 {
1352     tmp[0] = sample;
1353     if (factor > 1) {
1354         for (int f = 0; f < filters; f++)
1355             tmp[0] = filter[0][f].process(sample);
1356         for (int i = 1; i < factor; i++) {
1357             tmp[i] = 0;
1358             for (int f = 0; f < filters; f++)
1359                 tmp[i] = filter[0][f].process(sample);
1360         }
1361     }
1362     return tmp;
1363 }
1364 double resampleN::downsample(double *sample)
1365 {
1366     if (factor > 1) {
1367         for(int i = 0; i < factor; i++) {
1368             for (int f = 0; f < filters; f++) {
1369                 sample[i] = filter[1][f].process(sample[i]);
1370             }
1371         }
1372     }
1373     return sample[0];
1374 }
1375
1376 //////////////////////////////////////////////////////////////////
1377
1378 samplereduction::samplereduction()
1379 {
1380     target  = 0;
1381     real    = 0;
1382     samples = 0;
1383     last    = 0;
1384     amount  = 0;
1385     round   = 0;
1386 }
1387 void samplereduction::set_params(float am)
1388 {
1389     amount  = am;
1390     round   = roundf(amount);
1391     //samples = round;
1392 }
1393 double samplereduction::process(double in)
1394 {
1395     samples ++;
1396     if (samples >= round) {
1397         target += amount;
1398         real += round;
1399         if (target + amount >= real + 1) {
1400             last = in;
1401             target = 0;
1402             real   = 0;
1403         }
1404         samples = 0;
1405     }
1406     return last;
1407 }