X-Git-Url: https://git.sesse.net/?p=c64tapwav;a=blobdiff_plain;f=decode.cpp;h=b2878feb0e0a993c4ce37dc616c7f4453f8bbf73;hp=32e2cc3543e7c560915dc8955413687d5a121b6c;hb=0f23da84ab2a790a5a9450c1b05f6300362fc91c;hpb=2116cd5829fafa82e23eb328e01e76c876c7b781 diff --git a/decode.cpp b/decode.cpp index 32e2cc3..b2878fe 100644 --- a/decode.cpp +++ b/decode.cpp @@ -11,6 +11,7 @@ #include "interpolate.h" #include "level.h" #include "tap.h" +#include "filter.h" #define BUFSIZE 4096 #define C64_FREQUENCY 985248 @@ -19,19 +20,38 @@ #define SYNC_PULSE_LENGTH 378.0 #define SYNC_TEST_TOLERANCE 1.10 +// SPSA options #define NUM_FILTER_COEFF 32 +#define NUM_ITER 5000 +#define A NUM_ITER/10 // approx +#define INITIAL_A 0.005 // A bit of trial and error... +#define INITIAL_C 0.02 // This too. +#define GAMMA 0.166 +#define ALPHA 1.0 static float hysteresis_limit = 3000.0 / 32768.0; static bool do_calibrate = true; static bool output_cycles_plot = false; -static bool use_filter = false; static bool do_crop = false; static float crop_start = 0.0f, crop_end = HUGE_VAL; + +static bool use_fir_filter = false; static float filter_coeff[NUM_FILTER_COEFF] = { 1.0f }; // The rest is filled with 0. +static bool use_rc_filter = false; +static float rc_filter_freq; static bool output_filtered = false; + static bool quiet = false; static bool do_auto_level = false; static bool output_leveled = false; +static std::vector train_snap_points; +static bool do_train = false; + +// The minimum estimated sound level (for do_auto_level) at any given point. +// If you decrease this, you'll be able to amplify really silent signals +// by more, but you'll also increase the level of silent (ie. noise-only) segments, +// possibly caused misdetected pulses in these segments. +static float min_level = 0.05f; // between [x,x+1] double find_zerocrossing(const std::vector &pcm, int x) @@ -155,10 +175,12 @@ void output_tap(const std::vector& pulses, double calibration_factor) static struct option long_options[] = { {"auto-level", 0, 0, 'a' }, + {"output-leveled", 0, 0, 'A' }, {"no-calibrate", 0, 0, 's' }, {"plot-cycles", 0, 0, 'p' }, {"hysteresis-limit", required_argument, 0, 'l' }, {"filter", required_argument, 0, 'f' }, + {"rc-filter", required_argument, 0, 'r' }, {"output-filtered", 0, 0, 'F' }, {"crop", required_argument, 0, 'c' }, {"quiet", 0, 0, 'q' }, @@ -172,12 +194,16 @@ void help() fprintf(stderr, "\n"); fprintf(stderr, " -a, --auto-level automatically adjust amplitude levels throughout the file\n"); fprintf(stderr, " -A, --output-leveled output leveled waveform to leveled.raw\n"); + fprintf(stderr, " -m, --min-level minimum estimated sound level (0..32768) for --auto-level\n"); fprintf(stderr, " -s, --no-calibrate do not try to calibrate on sync pulse length\n"); fprintf(stderr, " -p, --plot-cycles output debugging info to cycles.plot\n"); fprintf(stderr, " -l, --hysteresis-limit VAL change amplitude threshold for ignoring pulses (0..32768)\n"); fprintf(stderr, " -f, --filter C1:C2:C3:... specify FIR filter (up to %d coefficients)\n", NUM_FILTER_COEFF); + fprintf(stderr, " -r, --rc-filter FREQ send signal through a highpass RC filter with given frequency (in Hertz)\n"); fprintf(stderr, " -F, --output-filtered output filtered waveform to filtered.raw\n"); fprintf(stderr, " -c, --crop START[:END] use only the given part of the file\n"); + fprintf(stderr, " -t, --train LEN1:LEN2:... train a filter for detecting any of the given number of cycles\n"); + fprintf(stderr, " (implies --no-calibrate and --quiet unless overridden)\n"); fprintf(stderr, " -q, --quiet suppress some informational messages\n"); fprintf(stderr, " -h, --help display this help, then exit\n"); exit(1); @@ -187,7 +213,7 @@ void parse_options(int argc, char **argv) { for ( ;; ) { int option_index = 0; - int c = getopt_long(argc, argv, "aAspl:f:Fc:qh", long_options, &option_index); + int c = getopt_long(argc, argv, "aAm:spl:f:r:Fc:t:qh", long_options, &option_index); if (c == -1) break; @@ -200,6 +226,10 @@ void parse_options(int argc, char **argv) output_leveled = true; break; + case 'm': + min_level = atof(optarg) / 32768.0; + break; + case 's': do_calibrate = false; break; @@ -213,16 +243,21 @@ void parse_options(int argc, char **argv) break; case 'f': { - const char *coeffstr = strtok(optarg, ":"); + const char *coeffstr = strtok(optarg, ": "); int coeff_index = 0; while (coeff_index < NUM_FILTER_COEFF && coeffstr != NULL) { filter_coeff[coeff_index++] = atof(coeffstr); - coeffstr = strtok(NULL, ":"); + coeffstr = strtok(NULL, ": "); } - use_filter = true; + use_fir_filter = true; break; } + case 'r': + use_rc_filter = true; + rc_filter_freq = atof(optarg); + break; + case 'F': output_filtered = true; break; @@ -240,6 +275,20 @@ void parse_options(int argc, char **argv) break; } + case 't': { + const char *cyclestr = strtok(optarg, ":"); + while (cyclestr != NULL) { + train_snap_points.push_back(atof(cyclestr)); + cyclestr = strtok(NULL, ":"); + } + do_train = true; + + // Set reasonable defaults (can be overridden later on the command line). + do_calibrate = false; + quiet = true; + break; + } + case 'q': quiet = true; break; @@ -265,7 +314,7 @@ std::vector crop(const std::vector& pcm, float crop_start, float c } // TODO: Support AVX here. -std::vector do_filter(const std::vector& pcm, const float* filter) +std::vector do_fir_filter(const std::vector& pcm, const float* filter) { std::vector filtered_pcm; filtered_pcm.reserve(pcm.size()); @@ -286,6 +335,24 @@ std::vector do_filter(const std::vector& pcm, const float* filter) return filtered_pcm; } +std::vector do_rc_filter(const std::vector& pcm, float freq, int sample_rate) +{ + std::vector filtered_pcm; + filtered_pcm.resize(pcm.size()); + Filter filter = Filter::hpf(M_PI * freq / sample_rate); + for (unsigned i = 0; i < pcm.size(); ++i) { + filtered_pcm[i] = filter.update(pcm[i]); + } + + if (output_filtered) { + FILE *fp = fopen("filtered.raw", "wb"); + fwrite(filtered_pcm.data(), filtered_pcm.size() * sizeof(filtered_pcm[0]), 1, fp); + fclose(fp); + } + + return filtered_pcm; +} + std::vector detect_pulses(const std::vector &pcm, int sample_rate) { std::vector pulses; @@ -343,6 +410,134 @@ void output_cycle_plot(const std::vector &pulses, double calibration_fact fclose(fp); } +std::pair find_closest_point(double x, const std::vector &points) +{ + int best_point = 0; + double best_dist = (x - points[0]) * (x - points[0]); + for (unsigned j = 1; j < train_snap_points.size(); ++j) { + double dist = (x - points[j]) * (x - points[j]); + if (dist < best_dist) { + best_point = j; + best_dist = dist; + } + } + return std::make_pair(best_point, best_dist); +} + +float eval_badness(const std::vector& pulses, double calibration_factor) +{ + double sum_badness = 0.0; + for (unsigned i = 0; i < pulses.size(); ++i) { + double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; + if (cycles > 2000.0) cycles = 2000.0; // Don't make pauses arbitrarily bad. + std::pair selected_point_and_sq_dist = find_closest_point(cycles, train_snap_points); + sum_badness += selected_point_and_sq_dist.second; + } + return sqrt(sum_badness / (pulses.size() - 1)); +} + +void find_kmeans(const std::vector &pulses, double calibration_factor, const std::vector &initial_centers) +{ + std::vector last_centers = initial_centers; + std::vector sums; + std::vector num; + sums.resize(initial_centers.size()); + num.resize(initial_centers.size()); + for ( ;; ) { + for (unsigned i = 0; i < initial_centers.size(); ++i) { + sums[i] = 0.0f; + num[i] = 0; + } + for (unsigned i = 0; i < pulses.size(); ++i) { + double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; + // Ignore heavy outliers, which are almost always long pauses. + if (cycles > 2000.0) { + continue; + } + std::pair selected_point_and_sq_dist = find_closest_point(cycles, last_centers); + int p = selected_point_and_sq_dist.first; + sums[p] += cycles; + ++num[p]; + } + bool any_moved = false; + for (unsigned i = 0; i < initial_centers.size(); ++i) { + if (num[i] == 0) { + printf("K-means broke down, can't output new reference training points\n"); + return; + } + float new_center = sums[i] / num[i]; + if (fabs(new_center - last_centers[i]) > 1e-3) { + any_moved = true; + } + last_centers[i] = new_center; + } + if (!any_moved) { + break; + } + } + printf("New reference training points:"); + for (unsigned i = 0; i < last_centers.size(); ++i) { + printf(" %.3f", last_centers[i]); + } + printf("\n"); +} + +void spsa_train(const std::vector &pcm, int sample_rate) +{ + float filter[NUM_FILTER_COEFF] = { 1.0f }; // The rest is filled with 0. + + float start_c = INITIAL_C; + double best_badness = HUGE_VAL; + + for (int n = 1; n < NUM_ITER; ++n) { + float a = INITIAL_A * pow(n + A, -ALPHA); + float c = start_c * pow(n, -GAMMA); + + // find a random perturbation + float p[NUM_FILTER_COEFF]; + float filter1[NUM_FILTER_COEFF], filter2[NUM_FILTER_COEFF]; + for (int i = 0; i < NUM_FILTER_COEFF; ++i) { + p[i] = (rand() % 2) ? 1.0 : -1.0; + filter1[i] = std::max(std::min(filter[i] - c * p[i], 1.0f), -1.0f); + filter2[i] = std::max(std::min(filter[i] + c * p[i], 1.0f), -1.0f); + } + + std::vector pulses1 = detect_pulses(do_fir_filter(pcm, filter1), sample_rate); + std::vector pulses2 = detect_pulses(do_fir_filter(pcm, filter2), sample_rate); + float badness1 = eval_badness(pulses1, 1.0); + float badness2 = eval_badness(pulses2, 1.0); + + // Find the gradient estimator + float g[NUM_FILTER_COEFF]; + for (int i = 0; i < NUM_FILTER_COEFF; ++i) { + g[i] = (badness2 - badness1) / (2.0 * c * p[i]); + filter[i] -= a * g[i]; + filter[i] = std::max(std::min(filter[i], 1.0f), -1.0f); + } + if (badness2 < badness1) { + std::swap(badness1, badness2); + std::swap(filter1, filter2); + std::swap(pulses1, pulses2); + } + if (badness1 < best_badness) { + printf("\nNew best filter (badness=%f):", badness1); + for (int i = 0; i < NUM_FILTER_COEFF; ++i) { + printf(" %.5f", filter1[i]); + } + best_badness = badness1; + printf("\n"); + + find_kmeans(pulses1, 1.0, train_snap_points); + + if (output_cycles_plot) { + output_cycle_plot(pulses1, 1.0); + } + } + printf("%d ", n); + fflush(stdout); + } +} + int main(int argc, char **argv) { parse_options(argc, argv); @@ -358,12 +553,16 @@ int main(int argc, char **argv) pcm = crop(pcm, crop_start, crop_end, sample_rate); } - if (use_filter) { - pcm = do_filter(pcm, filter_coeff); + if (use_fir_filter) { + pcm = do_fir_filter(pcm, filter_coeff); + } + + if (use_rc_filter) { + pcm = do_rc_filter(pcm, rc_filter_freq, sample_rate); } if (do_auto_level) { - pcm = level_samples(pcm, sample_rate); + pcm = level_samples(pcm, min_level, sample_rate); if (output_leveled) { FILE *fp = fopen("leveled.raw", "wb"); fwrite(pcm.data(), pcm.size() * sizeof(pcm[0]), 1, fp); @@ -383,6 +582,11 @@ int main(int argc, char **argv) } #endif + if (do_train) { + spsa_train(pcm, sample_rate); + exit(0); + } + std::vector pulses = detect_pulses(pcm, sample_rate); double calibration_factor = 1.0;