+// A program that tries to sync up the two channels, using Viterbi decoding
+// to find the most likely misalignment as it changes throughout the file.
+
+#define NUM_THEORIES 200
+#define THEORY_FROM -10.0 /* in samples */
+#define THEORY_TO 10.0 /* in samples */
+#define SWITCH_COST 1000.0 /* pretty arbitrary */
+
+#include <stdio.h>
+#include <math.h>
+#include <vector>
+#include <algorithm>
+
+#define LANCZOS_RADIUS 30
+#define BUFSIZE 4096
+
+struct stereo_sample {
+ short left, right;
+};
+struct double_stereo_sample {
+ double left, right;
+};
+
+inline short clip(int x)
+{
+ if (x < -32768) {
+ return x;
+ } else if (x > 32767) {
+ return 32767;
+ } else {
+ return short(x);
+ }
+}
+
+double sinc(double x)
+{
+ if (fabs(x) < 1e-6) {
+ return 1.0f - fabs(x);
+ } else {
+ return sin(x) / x;
+ }
+}
+
+#if 0
+double weight(double x)
+{
+ if (fabs(x) > LANCZOS_RADIUS) {
+ return 0.0f;
+ }
+ return sinc(M_PI * x) * sinc(M_PI * x / LANCZOS_RADIUS);
+}
+
+double interpolate(const std::vector<double_stereo_sample> &pcm, double i)
+{
+ int lower = std::max<int>(ceil(i - LANCZOS_RADIUS), 0);
+ int upper = std::min<int>(floor(i + LANCZOS_RADIUS), pcm.size() - 1);
+ double sum = 0.0f;
+
+ for (int x = lower; x <= upper; ++x) {
+ sum += pcm[x].right * weight(i - x);
+ }
+ return sum;
+}
+#else
+double weight(double x)
+{
+ if (fabs(x) > 1.0f) {
+ return 0.0f;
+ }
+ return 1.0f - fabs(x);
+}
+
+inline double interpolate(const std::vector<double> &pcm, double i)
+{
+ int ii = int(i);
+ if (ii < 0 || ii >= int(pcm.size() - 1)) {
+ return 0.0;
+ }
+ double frac = i - ii;
+
+ return pcm[ii] + frac * (pcm[ii + 1] - pcm[ii]);
+}
+
+template<class T>
+inline double interpolate(const std::vector<T> &pcm, double i)
+{
+ int ii = int(i);
+ if (ii < 0 || ii >= int(pcm.size() - 1)) {
+ return 0.0;
+ }
+ double frac = i - ii;
+
+ return pcm[ii].right + frac * (pcm[ii + 1].right - pcm[ii].right);
+}
+#endif
+
+struct hypothesis {
+ int id;
+ double cost;
+ hypothesis *prev;
+};
+
+int main(int argc, char **argv)
+{
+ std::vector<stereo_sample> pcm;
+
+ while (!feof(stdin)) {
+ stereo_sample buf[BUFSIZE];
+ ssize_t ret = fread(buf, sizeof(stereo_sample), BUFSIZE, stdin);
+ if (ret >= 0) {
+ pcm.insert(pcm.end(), buf, buf + ret);
+ }
+ }
+
+ double sum_left = 0.0, sum_right = 0.0;
+ for (unsigned i = 0; i < pcm.size(); ++i) {
+ sum_left += pcm[i].left;
+ sum_right += pcm[i].right;
+ }
+ double mean_left = sum_left / pcm.size();
+ double mean_right = sum_right / pcm.size();
+
+ //fprintf(stderr, "Mean: L=%f R=%f\n", mean_left, mean_right);
+
+ double sum2_left = 0.0, sum2_right = 0.0;
+ for (unsigned i = 0; i < pcm.size(); ++i) {
+ sum2_left += (pcm[i].left - mean_left) * (pcm[i].left - mean_left);
+ sum2_right += (pcm[i].right - mean_right) * (pcm[i].right - mean_right);
+ }
+ double var_left = sum2_left / (pcm.size() - 1);
+ double var_right = sum2_right / (pcm.size() - 1);
+
+ //fprintf(stderr, "Stddev: L=%f R=%f\n", sqrt(var_left), sqrt(var_right));
+
+ double inv_sd_left = 1.0 / sqrt(var_left);
+ double inv_sd_right = 1.0 / sqrt(var_right);
+
+ std::vector<double_stereo_sample> norm;
+ norm.resize(pcm.size());
+
+ for (unsigned i = 0; i < pcm.size(); ++i) {
+ norm[i].left = (pcm[i].left - mean_left) * inv_sd_left;
+ norm[i].right = (pcm[i].right - mean_right) * inv_sd_right;
+ }
+
+#if 0
+ double offset = 0.0;
+ double old_diff = 0.0;
+ for (unsigned i = 0; i < pcm.size(); ++i) {
+ double left = (pcm[i].left - mean_left) * inv_sd_left;
+ double right = (interpolate(pcm, i + offset) - mean_right) * inv_sd_right;
+
+ double diff = right - left;
+ old_diff = old_diff * 0.9999 + diff * 0.0001;
+ offset -= 0.1 * old_diff;
+
+ if (i % 100 == 0) {
+ fprintf(stderr, "%7.3f: %7.3f [diff=%8.3f lagged diff=%8.3f]\n", i / 44100.0, offset, diff, old_diff);
+ }
+ printf("%f %f %f\n", i / 44100.0, left, right);
+ }
+#endif
+
+ double delays[NUM_THEORIES];
+ hypothesis *bases = new hypothesis[NUM_THEORIES];
+
+ for (int h = 0; h < NUM_THEORIES; ++h) {
+ delays[h] = THEORY_FROM + h * (THEORY_TO - THEORY_FROM) / (NUM_THEORIES - 1);
+ bases[h].id = h;
+ bases[h].cost = 0.0;
+ bases[h].prev = NULL;
+ }
+
+ hypothesis *prev_hyp = bases;
+ size_t total_end = pcm.size();
+ //size_t total_end = 4410000;
+ for (unsigned i = 0; i < total_end; i += BUFSIZE) {
+ fprintf(stderr, "%.3f\n", i / 44100.0);
+ size_t end = std::min<size_t>(i + BUFSIZE, total_end);
+
+ hypothesis *hyp = new hypothesis[NUM_THEORIES];
+
+ // evaluate all hypotheses
+ for (int h = 0; h < NUM_THEORIES; ++h) {
+ double sum = 0.0;
+ double d = delays[h];
+ for (unsigned s = i; s < end; ++s) {
+ double left = norm[s].left;
+ double right = interpolate(norm, s + d);
+ double diff = (right - left) * (right - left);
+ sum += diff;
+ }
+
+ double best_cost = HUGE_VAL;
+ hypothesis *best_prev = NULL;
+ for (int hp = 0; hp < NUM_THEORIES; ++hp) {
+ double switch_cost = SWITCH_COST * fabs(delays[hp] - delays[h]);
+ double cost = prev_hyp[hp].cost + sum + switch_cost;
+ if (best_prev == NULL || cost < best_cost) {
+ best_cost = cost;
+ best_prev = &prev_hyp[hp];
+ }
+ }
+
+ hyp[h].id = h;
+ hyp[h].cost = best_cost;
+ hyp[h].prev = best_prev;
+ }
+
+ prev_hyp = hyp;
+ }
+
+ // best winner
+ double best_cost = HUGE_VAL;
+ hypothesis *best_hyp = NULL;
+ for (int h = 0; h < NUM_THEORIES; ++h) {
+ if (best_hyp == NULL || prev_hyp[h].cost < best_cost) {
+ best_cost = prev_hyp[h].cost;
+ best_hyp = &prev_hyp[h];
+ }
+ }
+
+ // trace the path backwards
+ std::vector<double> best_path;
+ while (best_hyp != NULL) {
+ best_path.push_back(delays[best_hyp->id]);
+ best_hyp = best_hyp->prev;
+ }
+
+ reverse(best_path.begin(), best_path.end());
+
+ fprintf(stderr, "Writing misalignment graphs to misalignment.plot...\n");
+ FILE *fp = fopen("misalignment.plot", "w");
+ for (unsigned i = 0; i < best_path.size(); ++i) {
+ fprintf(fp, "%f %f\n", i * BUFSIZE / 44100.0, best_path[i]);
+ }
+ fclose(fp);
+
+ // readjust and write out
+ double inv_sd = sqrt(2.0) / sqrt(var_left + var_right);
+ std::vector<stereo_sample> aligned_pcm;
+ std::vector<short> mono_pcm;
+ for (unsigned i = 0; i < total_end; ++i) {
+ double d = interpolate(best_path, i / double(BUFSIZE));
+ int left = pcm[i].left;
+ int right = interpolate(pcm, i + d);
+
+ stereo_sample ss;
+ ss.left = left;
+ ss.right = clip(right);
+ aligned_pcm.push_back(ss);
+
+ mono_pcm.push_back(clip(lrintf(inv_sd * 4096.0 * (left + right))));
+ }
+
+ fprintf(stderr, "Writing realigned stereo channels to aligned.raw...\n");
+ fp = fopen("aligned.raw", "wb");
+ fwrite(aligned_pcm.data(), sizeof(stereo_sample) * aligned_pcm.size(), 1, fp);
+ fclose(fp);
+
+ fprintf(stderr, "Writing combined mono track to combined.raw...\n");
+ fp = fopen("combined.raw", "wb");
+ fwrite(mono_pcm.data(), sizeof(short) * mono_pcm.size(), 1, fp);
+ fclose(fp);
+
+ fprintf(stderr, "All done.\n");
+
+#if 0
+
+ for (int sec = 0; sec < 2400; ++sec) {
+ double from_offset = -128.0;
+ double to_offset = 128.0;
+ double best_offset = HUGE_VAL;
+ for (int iter = 0; iter < 5; ++iter) {
+ //printf("from %f to %f\n", from_offset, to_offset);
+ double best_sum = HUGE_VAL;
+
+ for (int k = 0; k < 100; ++k) {
+ double offset = from_offset + k * 0.01 * (to_offset - from_offset);
+ double sum = 0.0;
+ for (unsigned i = sec * 4410; i < sec * 4410 + 4410; ++i) {
+ //for (unsigned i = 100000; i < 10NUM_THEORIES0; ++i) {
+ double left = norm[i].left;
+ double right = interpolate(norm, i + offset);
+ //double right = (norm[i + offset].right - mean_right) * inv_sd_right;
+ double diff = (right - left) * (right - left);
+ sum += diff;
+ }
+
+ if (sum < best_sum) {
+ best_sum = sum;
+ best_offset = offset;
+ }
+
+ //printf("%f %f\n", offset, sqrt(sum / NUM_THEORIES00.0f));
+ //fflush(stdout);
+ }
+
+ double range = 0.1 * (to_offset - from_offset);
+ from_offset = best_offset - range;
+ to_offset = best_offset + range;
+ }
+ printf("%d %f\n", sec, best_offset);
+ fflush(stdout);
+ }
+#endif
+
+
+}
projects / c64tapwav / commitdiff