X-Git-Url: https://git.sesse.net/?p=c64tapwav;a=blobdiff_plain;f=decode.cpp;h=ab242d0be5845f7145e0b40ca75c5a646207ca25;hp=49be647ea2cc67442718f2765e66ff508cd91064;hb=b0572bf7f70621037e6692c392965f2e85ea2590;hpb=8df851a0c512f869ef6b928cff20dd84a258e959 diff --git a/decode.cpp b/decode.cpp index 49be647..ab242d0 100644 --- a/decode.cpp +++ b/decode.cpp @@ -3,24 +3,47 @@ #include #include #include +#include #include #include +#include "audioreader.h" #include "interpolate.h" +#include "level.h" #include "tap.h" #define BUFSIZE 4096 -#define HYSTERESIS_LIMIT 3000 -#define SAMPLE_RATE 44100 #define C64_FREQUENCY 985248 - #define SYNC_PULSE_START 1000 -#define SYNC_PULSE_END 15000 +#define SYNC_PULSE_END 20000 #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 float filter_coeff[NUM_FILTER_COEFF] = { 1.0f }; // The rest is filled with 0. +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; + // between [x,x+1] -double find_zerocrossing(const std::vector &pcm, int x) +double find_zerocrossing(const std::vector &pcm, int x) { if (pcm[x] == 0) { return x; @@ -50,33 +73,247 @@ struct pulse { double time; // in seconds from start double len; // in seconds }; - -int main(int argc, char **argv) + +// Calibrate on the first ~25k pulses (skip a few, just to be sure). +double calibrate(const std::vector &pulses) { + if (pulses.size() < SYNC_PULSE_END) { + fprintf(stderr, "Too few pulses, not calibrating!\n"); + return 1.0; + } + + int sync_pulse_end = -1; + double sync_pulse_stddev = -1.0; + + // Compute the standard deviation (to check for uneven speeds). + // If it suddenly skyrockets, we assume that sync ended earlier + // than we thought (it should be 25000 cycles), and that we should + // calibrate on fewer cycles. + for (int try_end : { 2000, 4000, 5000, 7500, 10000, 15000, SYNC_PULSE_END }) { + double sum2 = 0.0; + for (int i = SYNC_PULSE_START; i < try_end; ++i) { + double cycles = pulses[i].len * C64_FREQUENCY; + sum2 += (cycles - SYNC_PULSE_LENGTH) * (cycles - SYNC_PULSE_LENGTH); + } + double stddev = sqrt(sum2 / (try_end - SYNC_PULSE_START - 1)); + if (sync_pulse_end != -1 && stddev > 5.0 && stddev / sync_pulse_stddev > 1.3) { + fprintf(stderr, "Stopping at %d sync pulses because standard deviation would be too big (%.2f cycles); shorter-than-usual trailer?\n", + sync_pulse_end, stddev); + break; + } + sync_pulse_end = try_end; + sync_pulse_stddev = stddev; + } + if (!quiet) { + fprintf(stderr, "Sync pulse length standard deviation: %.2f cycles\n", + sync_pulse_stddev); + } + + double sum = 0.0; + for (int i = SYNC_PULSE_START; i < sync_pulse_end; ++i) { + sum += pulses[i].len; + } + double mean_length = C64_FREQUENCY * sum / (sync_pulse_end - SYNC_PULSE_START); + double calibration_factor = SYNC_PULSE_LENGTH / mean_length; + if (!quiet) { + fprintf(stderr, "Calibrated sync pulse length: %.2f -> %.2f (change %+.2f%%)\n", + mean_length, SYNC_PULSE_LENGTH, 100.0 * (calibration_factor - 1.0)); + } + + // Check for pulses outside +/- 10% (sign of misdetection). + for (int i = SYNC_PULSE_START; i < sync_pulse_end; ++i) { + double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; + if (cycles < SYNC_PULSE_LENGTH / SYNC_TEST_TOLERANCE || cycles > SYNC_PULSE_LENGTH * SYNC_TEST_TOLERANCE) { + fprintf(stderr, "Sync cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n", + pulses[i].time, cycles); + } + } + + return calibration_factor; +} + +void output_tap(const std::vector& pulses, double calibration_factor) { - make_lanczos_weight_table(); - std::vector pcm; + std::vector tap_data; + for (unsigned i = 0; i < pulses.size(); ++i) { + double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; + int len = lrintf(cycles / TAP_RESOLUTION); + if (i > SYNC_PULSE_END && (cycles < 100 || cycles > 800)) { + fprintf(stderr, "Cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n", + pulses[i].time, cycles); + } + if (len <= 255) { + tap_data.push_back(len); + } else { + int overflow_len = lrintf(cycles); + tap_data.push_back(0); + tap_data.push_back(overflow_len & 0xff); + tap_data.push_back((overflow_len >> 8) & 0xff); + tap_data.push_back(overflow_len >> 16); + } + } - while (!feof(stdin)) { - short buf[BUFSIZE]; - ssize_t ret = fread(buf, 2, BUFSIZE, stdin); - if (ret >= 0) { - pcm.insert(pcm.end(), buf, buf + ret); + tap_header hdr; + memcpy(hdr.identifier, "C64-TAPE-RAW", 12); + hdr.version = 1; + hdr.reserved[0] = hdr.reserved[1] = hdr.reserved[2] = 0; + hdr.data_len = tap_data.size(); + + fwrite(&hdr, sizeof(hdr), 1, stdout); + fwrite(tap_data.data(), tap_data.size(), 1, stdout); +} + +static struct option long_options[] = { + {"auto-level", 0, 0, 'a' }, + {"no-calibrate", 0, 0, 's' }, + {"plot-cycles", 0, 0, 'p' }, + {"hysteresis-limit", required_argument, 0, 'l' }, + {"filter", required_argument, 0, 'f' }, + {"output-filtered", 0, 0, 'F' }, + {"crop", required_argument, 0, 'c' }, + {"quiet", 0, 0, 'q' }, + {"help", 0, 0, 'h' }, + {0, 0, 0, 0 } +}; + +void help() +{ + fprintf(stderr, "decode [OPTIONS] AUDIO-FILE > TAP-FILE\n"); + 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, " -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, " -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); +} + +void parse_options(int argc, char **argv) +{ + for ( ;; ) { + int option_index = 0; + int c = getopt_long(argc, argv, "aAspl:f:Fc:t:qh", long_options, &option_index); + if (c == -1) + break; + + switch (c) { + case 'a': + do_auto_level = true; + break; + + case 'A': + output_leveled = true; + break; + + case 's': + do_calibrate = false; + break; + + case 'p': + output_cycles_plot = true; + break; + + case 'l': + hysteresis_limit = atof(optarg) / 32768.0; + break; + + case 'f': { + 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, ": "); + } + use_filter = true; + break; } - } -#if 0 - for (int i = 0; i < LEN; ++i) { - in[i] += rand() % 10000; + case 'F': + output_filtered = true; + break; + + case 'c': { + const char *cropstr = strtok(optarg, ":"); + crop_start = atof(cropstr); + cropstr = strtok(NULL, ":"); + if (cropstr == NULL) { + crop_end = HUGE_VAL; + } else { + crop_end = atof(cropstr); + } + do_crop = true; + 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; + + case 'h': + default: + help(); + exit(1); + } } -#endif +} -#if 0 - for (int i = 0; i < LEN; ++i) { - printf("%d\n", in[i]); +std::vector crop(const std::vector& pcm, float crop_start, float crop_end, int sample_rate) +{ + size_t start_sample, end_sample; + if (crop_start >= 0.0f) { + start_sample = std::min(lrintf(crop_start * sample_rate), pcm.size()); } -#endif + if (crop_end >= 0.0f) { + end_sample = std::min(lrintf(crop_end * sample_rate), pcm.size()); + } + return std::vector(pcm.begin() + start_sample, pcm.begin() + end_sample); +} - std::vector pulses; // in seconds +// TODO: Support AVX here. +std::vector do_filter(const std::vector& pcm, const float* filter) +{ + std::vector filtered_pcm; + filtered_pcm.reserve(pcm.size()); + for (unsigned i = NUM_FILTER_COEFF; i < pcm.size(); ++i) { + float s = 0.0f; + for (int j = 0; j < NUM_FILTER_COEFF; ++j) { + s += filter[j] * pcm[i - j]; + } + filtered_pcm.push_back(s); + } + + 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; // Find the flanks. int last_bit = -1; @@ -84,14 +321,14 @@ int main(int argc, char **argv) for (unsigned i = 0; i < pcm.size(); ++i) { int bit = (pcm[i] > 0) ? 1 : 0; if (bit == 0 && last_bit == 1) { - // Check if we ever go up above HYSTERESIS_LIMIT before we dip down again. + // Check if we ever go up above before we dip down again. bool true_pulse = false; unsigned j; int min_level_after = 32767; for (j = i; j < pcm.size(); ++j) { min_level_after = std::min(min_level_after, pcm[j]); if (pcm[j] > 0) break; - if (pcm[j] < -HYSTERESIS_LIMIT) { + if (pcm[j] < -hysteresis_limit) { true_pulse = true; break; } @@ -100,14 +337,14 @@ int main(int argc, char **argv) if (!true_pulse) { #if 0 fprintf(stderr, "Ignored down-flank at %.6f seconds due to hysteresis (%d < %d).\n", - double(i) / SAMPLE_RATE, -min_level_after, HYSTERESIS_LIMIT); + double(i) / sample_rate, -min_level_after, hysteresis_limit); #endif i = j; continue; } // down-flank! - double t = find_zerocrossing(pcm, i - 1) * (1.0 / SAMPLE_RATE); + double t = find_zerocrossing(pcm, i - 1) * (1.0 / sample_rate) + crop_start; if (last_downflank > 0) { pulse p; p.time = t; @@ -118,85 +355,144 @@ int main(int argc, char **argv) } last_bit = bit; } + return pulses; +} - // Calibrate on the first ~25k pulses (skip a few, just to be sure). - double calibration_factor = 1.0f; - if (pulses.size() < SYNC_PULSE_END) { - fprintf(stderr, "Too few pulses, not calibrating!\n"); - } else { - double sum = 0.0; - for (int i = SYNC_PULSE_START; i < SYNC_PULSE_END; ++i) { - sum += pulses[i].len; - } - double mean_length = C64_FREQUENCY * sum / (SYNC_PULSE_END - SYNC_PULSE_START); - calibration_factor = SYNC_PULSE_LENGTH / mean_length; - fprintf(stderr, "Calibrated sync pulse length: %.2f -> %.2f (change %+.2f%%)\n", - mean_length, SYNC_PULSE_LENGTH, 100.0 * (calibration_factor - 1.0)); +void output_cycle_plot(const std::vector &pulses, double calibration_factor) +{ + FILE *fp = fopen("cycles.plot", "w"); + for (unsigned i = 0; i < pulses.size(); ++i) { + double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; + fprintf(fp, "%f %f\n", pulses[i].time, cycles); + } + fclose(fp); +} - // Check for pulses outside +/- 10% (sign of misdetection). - for (int i = SYNC_PULSE_START; i < SYNC_PULSE_END; ++i) { - double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; - if (cycles < SYNC_PULSE_LENGTH / SYNC_TEST_TOLERANCE || cycles > SYNC_PULSE_LENGTH * SYNC_TEST_TOLERANCE) { - fprintf(stderr, "Sync cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n", - pulses[i].time, cycles); - } +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. + double badness = (cycles - train_snap_points[0]) * (cycles - train_snap_points[0]); + for (unsigned j = 1; j < train_snap_points.size(); ++j) { + badness = std::min(badness, (cycles - train_snap_points[j]) * (cycles - train_snap_points[j])); } + sum_badness += badness; + } + return sqrt(sum_badness / (pulses.size() - 1)); +} - // Compute the standard deviation (to check for uneven speeds). - double sum2 = 0.0; - for (int i = SYNC_PULSE_START; i < SYNC_PULSE_END; ++i) { - double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; - sum2 += (cycles - SYNC_PULSE_LENGTH) * (cycles - SYNC_PULSE_LENGTH); +void spsa_train(std::vector &pcm, int sample_rate) +{ + // Train! + 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); } - double stddev = sqrt(sum2 / (SYNC_PULSE_END - SYNC_PULSE_START - 1)); - fprintf(stderr, "Sync pulse length standard deviation: %.2f cycles\n", - stddev); - } - FILE *fp = fopen("cycles.plot", "w"); - std::vector tap_data; - for (unsigned i = 0; i < pulses.size(); ++i) { - double cycles = pulses[i].len * calibration_factor * C64_FREQUENCY; - fprintf(fp, "%f %f\n", pulses[i].time, cycles); - int len = lrintf(cycles / TAP_RESOLUTION); - if (i > SYNC_PULSE_END && (cycles < 100 || cycles > 800)) { - fprintf(stderr, "Cycle with downflank at %.6f was detected at %.0f cycles; misdetect?\n", - pulses[i].time, cycles); + std::vector pulses1 = detect_pulses(do_filter(pcm, filter1), sample_rate); + std::vector pulses2 = detect_pulses(do_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 (len <= 255) { - tap_data.push_back(len); - } else { - int overflow_len = lrintf(cycles); - tap_data.push_back(0); - tap_data.push_back(overflow_len & 0xff); - tap_data.push_back((overflow_len >> 8) & 0xff); - tap_data.push_back(overflow_len >> 16); + 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"); + + if (output_cycles_plot) { + output_cycle_plot(pulses1, 1.0); + } } + printf("%d ", n); + fflush(stdout); } - fclose(fp); +} - tap_header hdr; - memcpy(hdr.identifier, "C64-TAPE-RAW", 12); - hdr.version = 1; - hdr.reserved[0] = hdr.reserved[1] = hdr.reserved[2] = 0; - hdr.data_len = tap_data.size(); +int main(int argc, char **argv) +{ + parse_options(argc, argv); - fwrite(&hdr, sizeof(hdr), 1, stdout); - fwrite(tap_data.data(), tap_data.size(), 1, stdout); + make_lanczos_weight_table(); + std::vector pcm; + int sample_rate; + if (!read_audio_file(argv[optind], &pcm, &sample_rate)) { + exit(1); + } - // Output a debug raw file with pulse detection points. - fp = fopen("debug.raw", "wb"); - short one = 32767; - short zero = 0; - unsigned pulsenum = 0; - for (unsigned i = 0; i < pcm.size(); ++i) { - unsigned next_pulse = (pulsenum >= pulses.size()) ? INT_MAX : int(pulses[pulsenum].time * SAMPLE_RATE); - if (i >= next_pulse) { - fwrite(&one, sizeof(one), 1, fp); - ++pulsenum; - } else { - fwrite(&zero, sizeof(zero), 1, fp); + if (do_crop) { + pcm = crop(pcm, crop_start, crop_end, sample_rate); + } + + if (use_filter) { + pcm = do_filter(pcm, filter_coeff); + } + + if (do_auto_level) { + pcm = level_samples(pcm, sample_rate); + if (output_leveled) { + FILE *fp = fopen("leveled.raw", "wb"); + fwrite(pcm.data(), pcm.size() * sizeof(pcm[0]), 1, fp); + fclose(fp); } } - fclose(fp); + +#if 0 + for (int i = 0; i < LEN; ++i) { + in[i] += rand() % 10000; + } +#endif + +#if 0 + for (int i = 0; i < LEN; ++i) { + printf("%d\n", in[i]); + } +#endif + + if (do_train) { + spsa_train(pcm, sample_rate); + exit(0); + } + + std::vector pulses = detect_pulses(pcm, sample_rate); + + double calibration_factor = 1.0; + if (do_calibrate) { + calibration_factor = calibrate(pulses); + } + + if (output_cycles_plot) { + output_cycle_plot(pulses, calibration_factor); + } + + output_tap(pulses, calibration_factor); }