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

   1 // A program that tries to sync up the two channels, using Viterbi decoding
   2 // to find the most likely misalignment as it changes throughout the file.
   3
   4 #define NUM_THEORIES 200
   5 #define THEORY_FROM -20.0  /* in samples */
   6 #define THEORY_TO 20.0  /* in samples */
   7 #define SWITCH_COST 1000.0  /* pretty arbitrary */
   8
   9 #include <stdio.h>
  10 #include <math.h>
  11 #include <vector>
  12 #include <algorithm>
  13
  14 #include "interpolate.h"
  15
  16 #define BUFSIZE 4096
  17
  18 struct stereo_sample {
  19         short left, right;
  20 };
  21 struct double_stereo_sample {
  22         double left, right;
  23 };
  24
  25 inline short clip(int x)
  26 {
  27         if (x < -32768) {
  28                 return x;
  29         } else if (x > 32767) {
  30                 return 32767;
  31         } else {
  32                 return short(x);
  33         }
  34 }
  35
  36 struct hypothesis {
  37         int id;
  38         double cost;
  39         hypothesis *prev;
  40 };
  41
  42 int main(int argc, char **argv)
  43 {
  44         make_lanczos_weight_table();
  45         std::vector<stereo_sample> pcm;
  46
  47         while (!feof(stdin)) {
  48                 stereo_sample buf[BUFSIZE];
  49                 ssize_t ret = fread(buf, sizeof(stereo_sample), BUFSIZE, stdin);
  50                 if (ret >= 0) {
  51                         pcm.insert(pcm.end(), buf, buf + ret);
  52                 }
  53         }
  54
  55         double sum_left = 0.0, sum_right = 0.0;
  56         for (unsigned i = 0; i < pcm.size(); ++i) {
  57                 sum_left += pcm[i].left;
  58                 sum_right += pcm[i].right;
  59         }
  60         double mean_left = sum_left / pcm.size();
  61         double mean_right = sum_right / pcm.size();
  62
  63         //fprintf(stderr, "Mean: L=%f R=%f\n", mean_left, mean_right);
  64
  65         double sum2_left = 0.0, sum2_right = 0.0;
  66         for (unsigned i = 0; i < pcm.size(); ++i) {
  67                 sum2_left += (pcm[i].left - mean_left) * (pcm[i].left - mean_left);
  68                 sum2_right += (pcm[i].right - mean_right) * (pcm[i].right - mean_right);
  69         }
  70         double var_left = sum2_left / (pcm.size() - 1);
  71         double var_right = sum2_right / (pcm.size() - 1);
  72
  73         //fprintf(stderr, "Stddev: L=%f R=%f\n", sqrt(var_left), sqrt(var_right));
  74
  75         double inv_sd_left = 1.0 / sqrt(var_left);
  76         double inv_sd_right = 1.0 / sqrt(var_right);
  77
  78         std::vector<double_stereo_sample> norm;
  79         norm.resize(pcm.size());
  80
  81         for (unsigned i = 0; i < pcm.size(); ++i) {
  82                 norm[i].left = (pcm[i].left - mean_left) * inv_sd_left;
  83                 norm[i].right = (pcm[i].right - mean_right) * inv_sd_right;
  84         }
  85
  86 #if 0
  87         double offset = 0.0;
  88         double old_diff = 0.0;
  89         for (unsigned i = 0; i < pcm.size(); ++i) {
  90                 double left = (pcm[i].left - mean_left) * inv_sd_left;
  91                 double right = (interpolate(pcm, i + offset) - mean_right) * inv_sd_right;
  92
  93                 double diff = right - left;
  94                 old_diff = old_diff * 0.9999 + diff * 0.0001;
  95                 offset -= 0.1 * old_diff;
  96
  97                 if (i % 100 == 0) {
  98                         fprintf(stderr, "%7.3f: %7.3f [diff=%8.3f lagged diff=%8.3f]\n", i / 44100.0, offset, diff, old_diff);
  99                 }
 100                 printf("%f %f %f\n", i / 44100.0, left, right);
 101         }
 102 #endif
 103
 104         double delays[NUM_THEORIES];
 105         hypothesis *bases = new hypothesis[NUM_THEORIES];
 106
 107         for (int h = 0; h < NUM_THEORIES; ++h) {
 108                 delays[h] = THEORY_FROM + h * (THEORY_TO - THEORY_FROM) / (NUM_THEORIES - 1);
 109                 bases[h].id = h;
 110                 bases[h].cost = 0.0;
 111                 bases[h].prev = NULL;
 112         }
 113
 114         fprintf(stderr, "Matching blocks... %7.2f", 0.0);
 115         hypothesis *prev_hyp = bases;
 116         size_t total_end = pcm.size();
 117         //size_t total_end = 441000;
 118         for (unsigned i = 0; i < total_end; i += BUFSIZE) {
 119                 fprintf(stderr, "\b\b\b\b\b\b\b%7.2f", i / 44100.0);
 120                 size_t end = std::min<size_t>(i + BUFSIZE, total_end);
 121
 122                 hypothesis *hyp = new hypothesis[NUM_THEORIES];
 123
 124                 // evaluate all hypotheses
 125                 for (int h = 0; h < NUM_THEORIES; ++h) {
 126                         double sum = 0.0;
 127                         double d = delays[h];
 128                         for (unsigned s = i; s < end; ++s) {
 129                                 double left = norm[s].left;
 130                                 double right = linear_interpolate_right(norm, s + d);
 131                                 double diff = (right - left) * (right - left);
 132                                 sum += diff;
 133                         }
 134
 135                         double best_cost = HUGE_VAL;
 136                         hypothesis *best_prev = NULL;
 137                         for (int hp = 0; hp < NUM_THEORIES; ++hp) {
 138                                 double switch_cost = SWITCH_COST * fabs(delays[hp] - delays[h]);
 139                                 double cost = prev_hyp[hp].cost + sum + switch_cost;
 140                                 if (best_prev == NULL || cost < best_cost) {
 141                                         best_cost = cost;
 142                                         best_prev = &prev_hyp[hp];
 143                                 }
 144                         }
 145
 146                         hyp[h].id = h;
 147                         hyp[h].cost = best_cost;
 148                         hyp[h].prev = best_prev;
 149                 }
 150
 151                 prev_hyp = hyp;
 152         }
 153         fprintf(stderr, "\b\b\b\b\b\b\b%7.2f\n", total_end / 44100.0);
 154
 155         // best winner
 156         double best_cost = HUGE_VAL;
 157         hypothesis *best_hyp = NULL;
 158         for (int h = 0; h < NUM_THEORIES; ++h) {
 159                 if (best_hyp == NULL || prev_hyp[h].cost < best_cost) {
 160                         best_cost = prev_hyp[h].cost;
 161                         best_hyp = &prev_hyp[h];
 162                 }
 163         }
 164
 165         // trace the path backwards
 166         std::vector<double> best_path;
 167         while (best_hyp != NULL) {
 168                 best_path.push_back(delays[best_hyp->id]);
 169                 best_hyp = best_hyp->prev;
 170         }
 171
 172         reverse(best_path.begin(), best_path.end());
 173
 174         fprintf(stderr, "Writing misalignment graphs to misalignment.plot...\n");
 175         FILE *fp = fopen("misalignment.plot", "w");
 176         for (unsigned i = 0; i < best_path.size(); ++i) {
 177                 fprintf(fp, "%f %f\n", i * BUFSIZE / 44100.0, best_path[i]);
 178         }
 179         fclose(fp);
 180
 181         fprintf(stderr, "Stretching right channel to match left... %7.2f%%", 0.0);
 182         double inv_sd = sqrt(2.0) / sqrt(var_left + var_right);
 183         std::vector<stereo_sample> aligned_pcm;
 184         std::vector<short> mono_pcm;
 185         aligned_pcm.resize(total_end);
 186         mono_pcm.resize(total_end);
 187         for (unsigned i = 0; i < total_end; ++i) {
 188                 double d = lanczos_interpolate(best_path, i / double(BUFSIZE));
 189                 int left = pcm[i].left;
 190                 int right = lanczos_interpolate_right(pcm, i + d);
 191
 192                 aligned_pcm[i].left = left;
 193                 aligned_pcm[i].right = clip(right);
 194
 195                 mono_pcm[i] = clip(lrintf(inv_sd * 4096.0 * (left + right)));
 196
 197                 if (i % 4096 == 0) {
 198                         fprintf(stderr, "\b\b\b\b\b\b\b\b%7.2f%%", 100.0 * i / total_end);
 199                 }
 200         }
 201         fprintf(stderr, "\b\b\b\b\b\b\b%7.2f%%\n", 100.0);
 202
 203         fprintf(stderr, "Writing realigned stereo channels to aligned.raw...\n");
 204         fp = fopen("aligned.raw", "wb");
 205         fwrite(aligned_pcm.data(), sizeof(stereo_sample) * aligned_pcm.size(), 1, fp);
 206         fclose(fp);
 207
 208         fprintf(stderr, "Writing combined mono track to combined.raw...\n");
 209         fp = fopen("combined.raw", "wb");
 210         fwrite(mono_pcm.data(), sizeof(short) * mono_pcm.size(), 1, fp);
 211         fclose(fp);
 212
 213         fprintf(stderr, "All done.\n");
 214
 215 #if 0
 216
 217         for (int sec = 0; sec < 2400; ++sec) {
 218                 double from_offset = -128.0;
 219                 double to_offset = 128.0;
 220                 double best_offset = HUGE_VAL;
 221                 for (int iter = 0; iter < 5; ++iter) {
 222                         //printf("from %f to %f\n", from_offset, to_offset);
 223                         double best_sum = HUGE_VAL;
 224
 225                         for (int k = 0; k < 100; ++k) {
 226                                 double offset = from_offset + k * 0.01 * (to_offset - from_offset);
 227                                 double sum = 0.0;
 228                                 for (unsigned i = sec * 4410; i < sec * 4410 + 4410; ++i) {
 229                                 //for (unsigned i = 100000; i < 10NUM_THEORIES0; ++i) {
 230                                         double left = norm[i].left;
 231                                         double right = interpolate(norm, i + offset);
 232                                         //double right = (norm[i + offset].right - mean_right) * inv_sd_right;
 233                                         double diff = (right - left) * (right - left);
 234                                         sum += diff;
 235                                 }
 236
 237                                 if (sum < best_sum) {
 238                                         best_sum = sum;
 239                                         best_offset = offset;
 240                                 }
 241
 242                                 //printf("%f %f\n", offset, sqrt(sum / NUM_THEORIES00.0f));
 243                                 //fflush(stdout);
 244                         }
 245
 246                         double range = 0.1 * (to_offset - from_offset);
 247                         from_offset = best_offset - range;
 248                         to_offset = best_offset + range;
 249                 }
 250                 printf("%d %f\n", sec, best_offset);
 251                 fflush(stdout);
 252         }
 253 #endif
 254
 255
 256 }