git.sesse.net Git - c64tapwav/blob - decode.cpp

   1 // Copyright Steinar H. Gunderson <sgunderson@bigfoot.com>
   2 // Licensed under the GPL, v2. (See the file COPYING.)
   3
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <math.h>
   7 #include <assert.h>
   8 #include <limits.h>
   9 #include <getopt.h>
  10 #include <vector>
  11 #include <algorithm>
  12
  13 #include "audioreader.h"
  14 #include "interpolate.h"
  15 #include "level.h"
  16 #include "tap.h"
  17 #include "filter.h"
  18
  19 #define BUFSIZE 4096
  20 #define C64_FREQUENCY 985248
  21 #define SYNC_PULSE_START 1000
  22 #define SYNC_PULSE_END 20000
  23 #define SYNC_PULSE_LENGTH 378.0
  24 #define SYNC_TEST_TOLERANCE 1.10
  25
  26 // SPSA options
  27 #define NUM_FILTER_COEFF 32
  28 #define NUM_ITER 5000
  29 #define A NUM_ITER/10  // approx
  30 #define INITIAL_A 0.005 // A bit of trial and error...
  31 #define INITIAL_C 0.02  // This too.
  32 #define GAMMA 0.166
  33 #define ALPHA 1.0
  34
  35 static float hysteresis_upper_limit = 3000.0 / 32768.0;
  36 static float hysteresis_lower_limit = -3000.0 / 32768.0;
  37 static bool do_calibrate = true;
  38 static bool output_cycles_plot = false;
  39 static bool do_crop = false;
  40 static float crop_start = 0.0f, crop_end = HUGE_VAL;
  41
  42 static bool use_fir_filter = false;
  43 static float filter_coeff[NUM_FILTER_COEFF] = { 1.0f };  // The rest is filled with 0.
  44 static bool use_rc_filter = false;
  45 static float rc_filter_freq;
  46 static bool output_filtered = false;
  47
  48 static bool quiet = false;
  49 static bool do_auto_level = false;
  50 static bool output_leveled = false;
  51 static std::vector<float> train_snap_points;
  52 static bool do_train = false;
  53
  54 // The minimum estimated sound level (for do_auto_level) at any given point.
  55 // If you decrease this, you'll be able to amplify really silent signals
  56 // by more, but you'll also increase the level of silent (ie. noise-only) segments,
  57 // possibly caused misdetected pulses in these segments.
  58 static float min_level = 0.05f;
  59
  60 // search for the value <limit> between [x,x+1]
  61 double find_crossing(const std::vector<float> &pcm, int x, float limit)
  62 {
  63         double upper = x;
  64         double lower = x + 1;
  65         while (lower - upper > 1e-3) {
  66                 double mid = 0.5f * (upper + lower);
  67                 if (lanczos_interpolate(pcm, mid) > limit) {
  68                         upper = mid;
  69                 } else {
  70                         lower = mid;
  71                 }
  72         }
  73
  74         return 0.5f * (upper + lower);
  75 }
  76
  77 struct pulse {
  78         double time;  // in seconds from start
  79         double len;   // in seconds
  80 };
  81
  82 // Calibrate on the first ~25k pulses (skip a few, just to be sure).
  83 double calibrate(const std::vector<pulse> &pulses) {
  84         if (pulses.size() < SYNC_PULSE_END) {
  85                 fprintf(stderr, "Too few pulses, not calibrating!\n");
  86                 return 1.0;
  87         }
  88
  89         int sync_pulse_end = -1;
  90         double sync_pulse_stddev = -1.0;
  91
  92         // Compute the standard deviation (to check for uneven speeds).
  93         // If it suddenly skyrockets, we assume that sync ended earlier
  94         // than we thought (it should be 25000 cycles), and that we should
  95         // calibrate on fewer cycles.
  96         for (int try_end : { 2000, 4000, 5000, 7500, 10000, 15000, SYNC_PULSE_END }) {
  97                 double sum2 = 0.0;
  98                 for (int i = SYNC_PULSE_START; i < try_end; ++i) {
  99                         double cycles = pulses[i].len * C64_FREQUENCY;
 100                         sum2 += (cycles - SYNC_PULSE_LENGTH) * (cycles - SYNC_PULSE_LENGTH);
 101                 }
 102                 double stddev = sqrt(sum2 / (try_end - SYNC_PULSE_START - 1));
 103                 if (sync_pulse_end != -1 && stddev > 5.0 && stddev / sync_pulse_stddev > 1.3) {
 104                         fprintf(stderr, "Stopping at %d sync pulses because standard deviation would be too big (%.2f cycles); shorter-than-usual trailer?\n",
 105                                 sync_pulse_end, stddev);
 106                         break;
 107                 }
 108                 sync_pulse_end = try_end;
 109                 sync_pulse_stddev = stddev;
 110         }
 111         if (!quiet) {
 112                 fprintf(stderr, "Sync pulse length standard deviation: %.2f cycles\n",
 113                         sync_pulse_stddev);
 114         }
 115
 116         double sum = 0.0;
 117         for (int i = SYNC_PULSE_START; i < sync_pulse_end; ++i) {
 118                 sum += pulses[i].len;
 119         }
 120         double mean_length = C64_FREQUENCY * sum / (sync_pulse_end - SYNC_PULSE_START);
 121         double calibration_factor = SYNC_PULSE_LENGTH / mean_length;
 122         if (!quiet) {
 123                 fprintf(stderr, "Calibrated sync pulse length: %.2f -> %.2f (change %+.2f%%)\n",
 124                         mean_length, SYNC_PULSE_LENGTH, 100.0 * (calibration_factor - 1.0));
 125         }
 126
 127         // Check for pulses outside +/- 10% (sign of misdetection).
 128         for (int i = SYNC_PULSE_START; i < sync_pulse_end; ++i) {
 129                 double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY;
 130                 if (cycles < SYNC_PULSE_LENGTH / SYNC_TEST_TOLERANCE || cycles > SYNC_PULSE_LENGTH * SYNC_TEST_TOLERANCE) {
 131                         fprintf(stderr, "Sync cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n",
 132                                 pulses[i].time, cycles);
 133                 }
 134         }
 135
 136         return calibration_factor;
 137 }
 138
 139 void output_tap(const std::vector<pulse>& pulses, double calibration_factor)
 140 {
 141         std::vector<char> tap_data;
 142         for (unsigned i = 0; i < pulses.size(); ++i) {
 143                 double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY;
 144                 int len = lrintf(cycles / TAP_RESOLUTION);
 145                 if (i > SYNC_PULSE_END && (cycles < 100 || cycles > 800)) {
 146                         fprintf(stderr, "Cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n",
 147                                         pulses[i].time, cycles);
 148                 }
 149                 if (len <= 255) {
 150                         tap_data.push_back(len);
 151                 } else {
 152                         int overflow_len = lrintf(cycles);
 153                         tap_data.push_back(0);
 154                         tap_data.push_back(overflow_len & 0xff);
 155                         tap_data.push_back((overflow_len >> 8) & 0xff);
 156                         tap_data.push_back(overflow_len >> 16);
 157                 }
 158         }
 159
 160         tap_header hdr;
 161         memcpy(hdr.identifier, "C64-TAPE-RAW", 12);
 162         hdr.version = 1;
 163         hdr.reserved[0] = hdr.reserved[1] = hdr.reserved[2] = 0;
 164         hdr.data_len = tap_data.size();
 165
 166         fwrite(&hdr, sizeof(hdr), 1, stdout);
 167         fwrite(tap_data.data(), tap_data.size(), 1, stdout);
 168 }
 169
 170 static struct option long_options[] = {
 171         {"auto-level",       0,                 0, 'a' },
 172         {"output-leveled",   0,                 0, 'A' },
 173         {"no-calibrate",     0,                 0, 's' },
 174         {"plot-cycles",      0,                 0, 'p' },
 175         {"hysteresis-limit", required_argument, 0, 'l' },
 176         {"filter",           required_argument, 0, 'f' },
 177         {"rc-filter",        required_argument, 0, 'r' },
 178         {"output-filtered",  0,                 0, 'F' },
 179         {"crop",             required_argument, 0, 'c' },
 180         {"quiet",            0,                 0, 'q' },
 181         {"help",             0,                 0, 'h' },
 182         {0,                  0,                 0, 0   }
 183 };
 184
 185 void help()
 186 {
 187         fprintf(stderr, "decode [OPTIONS] AUDIO-FILE > TAP-FILE\n");
 188         fprintf(stderr, "\n");
 189         fprintf(stderr, "  -a, --auto-level             automatically adjust amplitude levels throughout the file\n");
 190         fprintf(stderr, "  -A, --output-leveled         output leveled waveform to leveled.raw\n");
 191         fprintf(stderr, "  -m, --min-level              minimum estimated sound level (0..32768) for --auto-level\n");
 192         fprintf(stderr, "  -s, --no-calibrate           do not try to calibrate on sync pulse length\n");
 193         fprintf(stderr, "  -p, --plot-cycles            output debugging info to cycles.plot\n");
 194         fprintf(stderr, "  -l, --hysteresis-limit VAL   change amplitude threshold for ignoring pulses (0..32768)\n");
 195         fprintf(stderr, "  -f, --filter C1:C2:C3:...    specify FIR filter (up to %d coefficients)\n", NUM_FILTER_COEFF);
 196         fprintf(stderr, "  -r, --rc-filter FREQ         send signal through a highpass RC filter with given frequency (in Hertz)\n");
 197         fprintf(stderr, "  -F, --output-filtered        output filtered waveform to filtered.raw\n");
 198         fprintf(stderr, "  -c, --crop START[:END]       use only the given part of the file\n");
 199         fprintf(stderr, "  -t, --train LEN1:LEN2:...    train a filter for detecting any of the given number of cycles\n");
 200         fprintf(stderr, "                               (implies --no-calibrate and --quiet unless overridden)\n");
 201         fprintf(stderr, "  -q, --quiet                  suppress some informational messages\n");
 202         fprintf(stderr, "  -h, --help                   display this help, then exit\n");
 203         exit(1);
 204 }
 205
 206 void parse_options(int argc, char **argv)
 207 {
 208         for ( ;; ) {
 209                 int option_index = 0;
 210                 int c = getopt_long(argc, argv, "aAm:spl:f:r:Fc:t:qh", long_options, &option_index);
 211                 if (c == -1)
 212                         break;
 213
 214                 switch (c) {
 215                 case 'a':
 216                         do_auto_level = true;
 217                         break;
 218
 219                 case 'A':
 220                         output_leveled = true;
 221                         break;
 222
 223                 case 'm':
 224                         min_level = atof(optarg) / 32768.0;
 225                         break;
 226
 227                 case 's':
 228                         do_calibrate = false;
 229                         break;
 230
 231                 case 'p':
 232                         output_cycles_plot = true;
 233                         break;
 234
 235                 case 'l': {
 236                         const char *hyststr = strtok(optarg, ": ");
 237                         hysteresis_upper_limit = atof(hyststr) / 32768.0;
 238                         hyststr = strtok(NULL, ": ");
 239                         if (hyststr == NULL) {
 240                                 hysteresis_lower_limit = -hysteresis_upper_limit;
 241                         } else {
 242                                 hysteresis_lower_limit = atof(hyststr) / 32768.0;
 243                         }
 244                         break;
 245                 }
 246
 247                 case 'f': {
 248                         const char *coeffstr = strtok(optarg, ": ");
 249                         int coeff_index = 0;
 250                         while (coeff_index < NUM_FILTER_COEFF && coeffstr != NULL) {
 251                                 filter_coeff[coeff_index++] = atof(coeffstr);
 252                                 coeffstr = strtok(NULL, ": ");
 253                         }
 254                         use_fir_filter = true;
 255                         break;
 256                 }
 257
 258                 case 'r':
 259                         use_rc_filter = true;
 260                         rc_filter_freq = atof(optarg);
 261                         break;
 262
 263                 case 'F':
 264                         output_filtered = true;
 265                         break;
 266
 267                 case 'c': {
 268                         const char *cropstr = strtok(optarg, ":");
 269                         crop_start = atof(cropstr);
 270                         cropstr = strtok(NULL, ":");
 271                         if (cropstr == NULL) {
 272                                 crop_end = HUGE_VAL;
 273                         } else {
 274                                 crop_end = atof(cropstr);
 275                         }
 276                         do_crop = true;
 277                         break;
 278                 }
 279
 280                 case 't': {
 281                         const char *cyclestr = strtok(optarg, ":");
 282                         while (cyclestr != NULL) {
 283                                 train_snap_points.push_back(atof(cyclestr));
 284                                 cyclestr = strtok(NULL, ":");
 285                         }
 286                         do_train = true;
 287
 288                         // Set reasonable defaults (can be overridden later on the command line).
 289                         do_calibrate = false;
 290                         quiet = true;
 291                         break;
 292                 }
 293
 294                 case 'q':
 295                         quiet = true;
 296                         break;
 297
 298                 case 'h':
 299                 default:
 300                         help();
 301                         exit(1);
 302                 }
 303         }
 304 }
 305
 306 std::vector<float> crop(const std::vector<float>& pcm, float crop_start, float crop_end, int sample_rate)
 307 {
 308         size_t start_sample, end_sample;
 309         if (crop_start >= 0.0f) {
 310                 start_sample = std::min<size_t>(lrintf(crop_start * sample_rate), pcm.size());
 311         }
 312         if (crop_end >= 0.0f) {
 313                 end_sample = std::min<size_t>(lrintf(crop_end * sample_rate), pcm.size());
 314         }
 315         return std::vector<float>(pcm.begin() + start_sample, pcm.begin() + end_sample);
 316 }
 317
 318 // TODO: Support AVX here.
 319 std::vector<float> do_fir_filter(const std::vector<float>& pcm, const float* filter)
 320 {
 321         std::vector<float> filtered_pcm;
 322         filtered_pcm.reserve(pcm.size());
 323         for (unsigned i = NUM_FILTER_COEFF; i < pcm.size(); ++i) {
 324                 float s = 0.0f;
 325                 for (int j = 0; j < NUM_FILTER_COEFF; ++j) {
 326                         s += filter[j] * pcm[i - j];
 327                 }
 328                 filtered_pcm.push_back(s);
 329         }
 330
 331         if (output_filtered) {
 332                 FILE *fp = fopen("filtered.raw", "wb");
 333                 fwrite(filtered_pcm.data(), filtered_pcm.size() * sizeof(filtered_pcm[0]), 1, fp);
 334                 fclose(fp);
 335         }
 336
 337         return filtered_pcm;
 338 }
 339
 340 std::vector<float> do_rc_filter(const std::vector<float>& pcm, float freq, int sample_rate)
 341 {
 342         // This is only a 6 dB/oct filter, which seemingly works better
 343         // than the Filter class, which is a standard biquad (12 dB/oct).
 344         // The b/c calculations come from libnyquist (atone.c);
 345         // I haven't checked, but I suppose they fall out of the bilinear
 346         // transform of the transfer function H(s) = s/(s + w).
 347         std::vector<float> filtered_pcm;
 348         filtered_pcm.resize(pcm.size());
 349         const float b = 2.0f - cos(2.0 * M_PI * freq / sample_rate);
 350         const float c = b - sqrt(b * b - 1.0f);
 351         float prev_in = 0.0f;
 352         float prev_out = 0.0f;
 353         for (unsigned i = 0; i < pcm.size(); ++i) {
 354                 float in = pcm[i];
 355                 float out = c * (prev_out + in - prev_in);
 356                 filtered_pcm[i] = out;
 357                 prev_in = in;
 358                 prev_out = out;
 359         }
 360
 361         if (output_filtered) {
 362                 FILE *fp = fopen("filtered.raw", "wb");
 363                 fwrite(filtered_pcm.data(), filtered_pcm.size() * sizeof(filtered_pcm[0]), 1, fp);
 364                 fclose(fp);
 365         }
 366
 367         return filtered_pcm;
 368 }
 369
 370 std::vector<pulse> detect_pulses(const std::vector<float> &pcm, int sample_rate)
 371 {
 372         std::vector<pulse> pulses;
 373
 374         // Find the flanks.
 375         enum State { START, ABOVE, BELOW } state = START;
 376         double last_downflank = -1;
 377         for (unsigned i = 0; i < pcm.size(); ++i) {
 378                 if (pcm[i] > hysteresis_upper_limit) {
 379                         state = ABOVE;
 380                 } else if (pcm[i] < hysteresis_lower_limit) {
 381                         if (state == ABOVE) {
 382                                 // down-flank!
 383                                 double t = find_crossing(pcm, i - 1, hysteresis_lower_limit) * (1.0 / sample_rate) + crop_start;
 384                                 if (last_downflank > 0) {
 385                                         pulse p;
 386                                         p.time = t;
 387                                         p.len = t - last_downflank;
 388                                         pulses.push_back(p);
 389                                 }
 390                                 last_downflank = t;
 391                         }
 392                         state = BELOW;
 393                 }
 394         }
 395         return pulses;
 396 }
 397
 398 void output_cycle_plot(const std::vector<pulse> &pulses, double calibration_factor)
 399 {
 400         FILE *fp = fopen("cycles.plot", "w");
 401         for (unsigned i = 0; i < pulses.size(); ++i) {
 402                 double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY;
 403                 fprintf(fp, "%f %f\n", pulses[i].time, cycles);
 404         }
 405         fclose(fp);
 406 }
 407
 408 std::pair<int, double> find_closest_point(double x, const std::vector<float> &points)
 409 {
 410         int best_point = 0;
 411         double best_dist = (x - points[0]) * (x - points[0]);
 412         for (unsigned j = 1; j < train_snap_points.size(); ++j) {
 413                 double dist = (x - points[j]) * (x - points[j]);
 414                 if (dist < best_dist) {
 415                         best_point = j;
 416                         best_dist = dist;
 417                 }
 418         }
 419         return std::make_pair(best_point, best_dist);
 420 }
 421
 422 float eval_badness(const std::vector<pulse>& pulses, double calibration_factor)
 423 {
 424         double sum_badness = 0.0;
 425         for (unsigned i = 0; i < pulses.size(); ++i) {
 426                 double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY;
 427                 if (cycles > 2000.0) cycles = 2000.0;  // Don't make pauses arbitrarily bad.
 428                 std::pair<int, double> selected_point_and_sq_dist = find_closest_point(cycles, train_snap_points);
 429                 sum_badness += selected_point_and_sq_dist.second;
 430         }
 431         return sqrt(sum_badness / (pulses.size() - 1));
 432 }
 433
 434 void find_kmeans(const std::vector<pulse> &pulses, double calibration_factor, const std::vector<float> &initial_centers)
 435 {
 436         std::vector<float> last_centers = initial_centers;
 437         std::vector<float> sums;
 438         std::vector<float> num;
 439         sums.resize(initial_centers.size());
 440         num.resize(initial_centers.size());
 441         for ( ;; ) {
 442                 for (unsigned i = 0; i < initial_centers.size(); ++i) {
 443                         sums[i] = 0.0f;
 444                         num[i] = 0;
 445                 }
 446                 for (unsigned i = 0; i < pulses.size(); ++i) {
 447                         double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY;
 448                         // Ignore heavy outliers, which are almost always long pauses.
 449                         if (cycles > 2000.0) {
 450                                 continue;
 451                         }
 452                         std::pair<int, double> selected_point_and_sq_dist = find_closest_point(cycles, last_centers);
 453                         int p = selected_point_and_sq_dist.first;
 454                         sums[p] += cycles;
 455                         ++num[p];
 456                 }
 457                 bool any_moved = false;
 458                 for (unsigned i = 0; i < initial_centers.size(); ++i) {
 459                         if (num[i] == 0) {
 460                                 fprintf(stderr, "K-means broke down, can't output new reference training points\n");
 461                                 return;
 462                         }
 463                         float new_center = sums[i] / num[i];
 464                         if (fabs(new_center - last_centers[i]) > 1e-3) {
 465                                 any_moved = true;
 466                         }
 467                         last_centers[i] = new_center;
 468                 }
 469                 if (!any_moved) {
 470                         break;
 471                 }
 472         }
 473         fprintf(stderr, "New reference training points:");
 474         for (unsigned i = 0; i < last_centers.size(); ++i) {
 475                 fprintf(stderr, " %.3f", last_centers[i]);
 476         }
 477         fprintf(stderr, "\n");
 478 }
 479
 480 void spsa_train(const std::vector<float> &pcm, int sample_rate)
 481 {
 482         float filter[NUM_FILTER_COEFF] = { 1.0f };  // The rest is filled with 0.
 483
 484         float start_c = INITIAL_C;
 485         double best_badness = HUGE_VAL;
 486
 487         for (int n = 1; n < NUM_ITER; ++n) {
 488                 float a = INITIAL_A * pow(n + A, -ALPHA);
 489                 float c = start_c * pow(n, -GAMMA);
 490
 491                 // find a random perturbation
 492                 float p[NUM_FILTER_COEFF];
 493                 float filter1[NUM_FILTER_COEFF], filter2[NUM_FILTER_COEFF];
 494                 for (int i = 0; i < NUM_FILTER_COEFF; ++i) {
 495                         p[i] = (rand() % 2) ? 1.0 : -1.0;
 496                         filter1[i] = std::max(std::min(filter[i] - c * p[i], 1.0f), -1.0f);
 497                         filter2[i] = std::max(std::min(filter[i] + c * p[i], 1.0f), -1.0f);
 498                 }
 499
 500                 std::vector<pulse> pulses1 = detect_pulses(do_fir_filter(pcm, filter1), sample_rate);
 501                 std::vector<pulse> pulses2 = detect_pulses(do_fir_filter(pcm, filter2), sample_rate);
 502                 float badness1 = eval_badness(pulses1, 1.0);
 503                 float badness2 = eval_badness(pulses2, 1.0);
 504
 505                 // Find the gradient estimator
 506                 float g[NUM_FILTER_COEFF];
 507                 for (int i = 0; i < NUM_FILTER_COEFF; ++i) {
 508                         g[i] = (badness2 - badness1) / (2.0 * c * p[i]);
 509                         filter[i] -= a * g[i];
 510                         filter[i] = std::max(std::min(filter[i], 1.0f), -1.0f);
 511                 }
 512                 if (badness2 < badness1) {
 513                         std::swap(badness1, badness2);
 514                         std::swap(filter1, filter2);
 515                         std::swap(pulses1, pulses2);
 516                 }
 517                 if (badness1 < best_badness) {
 518                         printf("\nNew best filter (badness=%f):", badness1);
 519                         for (int i = 0; i < NUM_FILTER_COEFF; ++i) {
 520                                 printf(" %.5f", filter1[i]);
 521                         }
 522                         best_badness = badness1;
 523                         printf("\n");
 524
 525                         find_kmeans(pulses1, 1.0, train_snap_points);
 526
 527                         if (output_cycles_plot) {
 528                                 output_cycle_plot(pulses1, 1.0);
 529                         }
 530                 }
 531                 printf("%d ", n);
 532                 fflush(stdout);
 533         }
 534 }
 535
 536 int main(int argc, char **argv)
 537 {
 538         parse_options(argc, argv);
 539
 540         make_lanczos_weight_table();
 541         std::vector<float> pcm;
 542         int sample_rate;
 543         if (!read_audio_file(argv[optind], &pcm, &sample_rate)) {
 544                 exit(1);
 545         }
 546
 547         if (do_crop) {
 548                 pcm = crop(pcm, crop_start, crop_end, sample_rate);
 549         }
 550
 551         if (use_fir_filter) {
 552                 pcm = do_fir_filter(pcm, filter_coeff);
 553         }
 554
 555         if (use_rc_filter) {
 556                 pcm = do_rc_filter(pcm, rc_filter_freq, sample_rate);
 557         }
 558
 559         if (do_auto_level) {
 560                 pcm = level_samples(pcm, min_level, sample_rate);
 561                 if (output_leveled) {
 562                         FILE *fp = fopen("leveled.raw", "wb");
 563                         fwrite(pcm.data(), pcm.size() * sizeof(pcm[0]), 1, fp);
 564                         fclose(fp);
 565                 }
 566         }
 567
 568 #if 0
 569         for (int i = 0; i < LEN; ++i) {
 570                 in[i] += rand() % 10000;
 571         }
 572 #endif
 573
 574 #if 0
 575         for (int i = 0; i < LEN; ++i) {
 576                 printf("%d\n", in[i]);
 577         }
 578 #endif
 579
 580         if (do_train) {
 581                 spsa_train(pcm, sample_rate);
 582                 exit(0);
 583         }
 584
 585         std::vector<pulse> pulses = detect_pulses(pcm, sample_rate);
 586
 587         double calibration_factor = 1.0;
 588         if (do_calibrate) {
 589                 calibration_factor = calibrate(pulses);
 590         }
 591
 592         if (output_cycles_plot) {
 593                 output_cycle_plot(pulses, calibration_factor);
 594         }
 595
 596         output_tap(pulses, calibration_factor);
 597 }