X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=decode.cpp;h=94bc1dd1668abe0482d6071e3de40082741806e1;hb=b55d61c30b6c2158589de0d0584a6dcc590e52dd;hp=c547311107560eafb9181d3e069f73d7b560ba58;hpb=5849f2d7f8b5de6b6749662aee23ef95132437c1;p=c64tapwav diff --git a/decode.cpp b/decode.cpp index c547311..94bc1dd 100644 --- a/decode.cpp +++ b/decode.cpp @@ -3,6 +3,7 @@ #include #include #include +#include #include #include @@ -11,14 +12,21 @@ #include "tap.h" #define BUFSIZE 4096 -#define HYSTERESIS_LIMIT (3000/32768.0) #define C64_FREQUENCY 985248 - #define SYNC_PULSE_START 1000 #define SYNC_PULSE_END 20000 #define SYNC_PULSE_LENGTH 378.0 #define SYNC_TEST_TOLERANCE 1.10 +#define NUM_FILTER_COEFF 32 + +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 float filter_coeff[NUM_FILTER_COEFF] = { 1.0f }; // The rest is filled with 0. +static bool output_filtered = false; + // between [x,x+1] double find_zerocrossing(const std::vector &pcm, int x) { @@ -134,16 +142,110 @@ void output_tap(const std::vector& pulses, double calibration_factor) fwrite(&hdr, sizeof(hdr), 1, stdout); fwrite(tap_data.data(), tap_data.size(), 1, stdout); } - + +static struct option long_options[] = { + {"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' }, + {"help", 0, 0, 'h' }, + {0, 0, 0, 0 } +}; + +void help() +{ + fprintf(stderr, "decode [OPTIONS] AUDIO-FILE > TAP-FILE\n"); + fprintf(stderr, "\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, " -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, "spl:f:Fh", long_options, &option_index); + if (c == -1) + break; + + switch (c) { + 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; + } + + case 'F': + output_filtered = true; + break; + + case 'h': + default: + help(); + exit(1); + } + } +} + +// 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; +} + int main(int argc, char **argv) { + parse_options(argc, argv); + make_lanczos_weight_table(); std::vector pcm; int sample_rate; - if (!read_audio_file(argv[1], &pcm, &sample_rate)) { + if (!read_audio_file(argv[optind], &pcm, &sample_rate)) { exit(1); } + if (use_filter) { + pcm = do_filter(pcm, filter_coeff); + } + #if 0 for (int i = 0; i < LEN; ++i) { in[i] += rand() % 10000; @@ -164,14 +266,14 @@ 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; } @@ -180,7 +282,7 @@ 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; @@ -199,15 +301,19 @@ int main(int argc, char **argv) last_bit = bit; } - double calibration_factor = calibrate(pulses); + double calibration_factor = 1.0; + if (do_calibrate) { + calibration_factor = calibrate(pulses); + } - 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); + if (output_cycles_plot) { + 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); } - fclose(fp); output_tap(pulses, calibration_factor); }