#include <math.h>
#include <assert.h>
#include <limits.h>
+#include <getopt.h>
#include <vector>
#include <algorithm>
#include "tap.h"
#define BUFSIZE 4096
-#define HYSTERESIS_LIMIT 3000
#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;
+static bool quiet = false;
+
// between [x,x+1]
double find_zerocrossing(const std::vector<float> &pcm, int x)
{
sync_pulse_end = try_end;
sync_pulse_stddev = stddev;
}
- fprintf(stderr, "Sync pulse length standard deviation: %.2f cycles\n",
- sync_pulse_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) {
}
double mean_length = C64_FREQUENCY * sum / (sync_pulse_end - SYNC_PULSE_START);
double 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));
+ 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) {
fwrite(&hdr, sizeof(hdr), 1, stdout);
fwrite(tap_data.data(), tap_data.size(), 1, stdout);
}
-
-int main(int argc, char **argv)
+
+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' },
+ {"quiet", 0, 0, 'q' },
+ {"help", 0, 0, 'h' },
+ {0, 0, 0, 0 }
+};
+
+void help()
{
- make_lanczos_weight_table();
- std::vector<float> pcm;
- int sample_rate;
- if (!read_audio_file(argv[1], &pcm, &sample_rate)) {
- exit(1);
+ 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, " -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, "spl:f:Fqh", 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 'q':
+ quiet = true;
+ break;
+
+ case 'h':
+ default:
+ help();
+ exit(1);
+ }
}
+}
-#if 0
- for (int i = 0; i < LEN; ++i) {
- in[i] += rand() % 10000;
+// TODO: Support AVX here.
+std::vector<float> do_filter(const std::vector<float>& pcm, const float* filter)
+{
+ std::vector<float> 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);
}
-#endif
-#if 0
- for (int i = 0; i < LEN; ++i) {
- printf("%d\n", in[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);
}
-#endif
- std::vector<pulse> pulses; // in seconds
+ return filtered_pcm;
+}
+
+std::vector<pulse> detect_pulses(const std::vector<float> &pcm, int sample_rate)
+{
+ std::vector<pulse> pulses;
// Find the flanks.
int last_bit = -1;
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 <hysteresis_limit> 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<int>(min_level_after, pcm[j]);
if (pcm[j] > 0) break;
- if (pcm[j] < -HYSTERESIS_LIMIT) {
+ if (pcm[j] < -hysteresis_limit) {
true_pulse = true;
break;
}
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;
}
last_bit = bit;
}
+ return pulses;
+}
- double calibration_factor = calibrate(pulses);
+int main(int argc, char **argv)
+{
+ parse_options(argc, argv);
- FILE *fp = fopen("cycles.plot", "w");
- std::vector<char> 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);
+ make_lanczos_weight_table();
+ std::vector<float> pcm;
+ int 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;
+ }
+#endif
+
+#if 0
+ for (int i = 0; i < LEN; ++i) {
+ printf("%d\n", in[i]);
+ }
+#endif
+
+ std::vector<pulse> pulses = detect_pulses(pcm, sample_rate);
+
+ double calibration_factor = 1.0;
+ if (do_calibrate) {
+ calibration_factor = calibrate(pulses);
+ }
+
+ 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);
}
projects / c64tapwav / blobdiff