X-Git-Url: https://git.sesse.net/?p=c64tapwav;a=blobdiff_plain;f=decode.cpp;h=839c2619d91824b0fc49417942c20f6e038690a9;hp=f645588923bcb079f6f30b52f505f07535ab71f8;hb=a04e2b22877ea003dbb8495373497ce0a24a8595;hpb=d60a4236e895ac9ff1e3aa46be89707bace121d8 diff --git a/decode.cpp b/decode.cpp index f645588..839c261 100644 --- a/decode.cpp +++ b/decode.cpp @@ -32,7 +32,8 @@ #define GAMMA 0.166 #define ALPHA 1.0 -static float hysteresis_limit = 3000.0 / 32768.0; +static float hysteresis_upper_limit = 0.1; +static float hysteresis_lower_limit = -0.1; static bool do_calibrate = true; static bool output_cycles_plot = false; static bool do_crop = false; @@ -50,30 +51,25 @@ static bool output_leveled = false; static std::vector train_snap_points; static bool do_train = false; +// The frequency to filter on (for do_auto_level), in Hertz. +// Larger values makes the compressor react faster, but if it is too large, +// you'll ruin the waveforms themselves. +static float auto_level_freq = 200.0; + // 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) +// search for the value between [x,x+1] +double find_crossing(const std::vector &pcm, int x, float limit) { - if (pcm[x] == 0) { - return x; - } - if (pcm[x + 1] == 0) { - return x + 1; - } - - assert(pcm[x + 1] < 0); - assert(pcm[x] > 0); - double upper = x; double lower = x + 1; while (lower - upper > 1e-3) { double mid = 0.5f * (upper + lower); - if (lanczos_interpolate(pcm, mid) > 0) { + if (lanczos_interpolate(pcm, mid) > limit) { upper = mid; } else { lower = mid; @@ -178,7 +174,9 @@ void output_tap(const std::vector& pulses, double calibration_factor) static struct option long_options[] = { {"auto-level", 0, 0, 'a' }, + {"auto-level-freq", required_argument, 0, 'b' }, {"output-leveled", 0, 0, 'A' }, + {"min-level", required_argument, 0, 'm' }, {"no-calibrate", 0, 0, 's' }, {"plot-cycles", 0, 0, 'p' }, {"hysteresis-limit", required_argument, 0, 'l' }, @@ -196,11 +194,12 @@ 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, " -b, --auto-level-freq minimum frequency in Hertz of corrected level changes (default 200 Hz)\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, " -m, --min-level minimum estimated sound level (0..1) 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, " -l, --hysteresis-limit U[:L] change amplitude threshold for ignoring pulses (-1..1)\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"); @@ -216,7 +215,7 @@ void parse_options(int argc, char **argv) { for ( ;; ) { int option_index = 0; - int c = getopt_long(argc, argv, "aAm:spl:f:r:Fc:t:qh", long_options, &option_index); + int c = getopt_long(argc, argv, "ab:Am:spl:f:r:Fc:t:qh", long_options, &option_index); if (c == -1) break; @@ -225,12 +224,16 @@ void parse_options(int argc, char **argv) do_auto_level = true; break; + case 'b': + auto_level_freq = atof(optarg); + break; + case 'A': output_leveled = true; break; case 'm': - min_level = atof(optarg) / 32768.0; + min_level = atof(optarg); break; case 's': @@ -241,9 +244,17 @@ void parse_options(int argc, char **argv) output_cycles_plot = true; break; - case 'l': - hysteresis_limit = atof(optarg) / 32768.0; + case 'l': { + const char *hyststr = strtok(optarg, ": "); + hysteresis_upper_limit = atof(hyststr); + hyststr = strtok(NULL, ": "); + if (hyststr == NULL) { + hysteresis_lower_limit = -hysteresis_upper_limit; + } else { + hysteresis_lower_limit = atof(hyststr); + } break; + } case 'f': { const char *coeffstr = strtok(optarg, ": "); @@ -373,44 +384,25 @@ std::vector detect_pulses(const std::vector &pcm, int sample_rate) std::vector pulses; // Find the flanks. - int last_bit = -1; + enum State { START, ABOVE, BELOW } state = START; double last_downflank = -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 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) { - true_pulse = true; - break; + if (pcm[i] > hysteresis_upper_limit) { + state = ABOVE; + } else if (pcm[i] < hysteresis_lower_limit) { + if (state == ABOVE) { + // down-flank! + double t = find_crossing(pcm, i - 1, hysteresis_lower_limit) * (1.0 / sample_rate) + crop_start; + if (last_downflank > 0) { + pulse p; + p.time = t; + p.len = t - last_downflank; + pulses.push_back(p); } + last_downflank = t; } - - 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); -#endif - i = j; - continue; - } - - // down-flank! - double t = find_zerocrossing(pcm, i - 1) * (1.0 / sample_rate) + crop_start; - if (last_downflank > 0) { - pulse p; - p.time = t; - p.len = t - last_downflank; - pulses.push_back(p); - } - last_downflank = t; + state = BELOW; } - last_bit = bit; } return pulses; } @@ -577,7 +569,7 @@ int main(int argc, char **argv) } if (do_auto_level) { - pcm = level_samples(pcm, min_level, sample_rate); + pcm = level_samples(pcm, min_level, auto_level_freq, sample_rate); if (output_leveled) { FILE *fp = fopen("leveled.raw", "wb"); fwrite(pcm.data(), pcm.size() * sizeof(pcm[0]), 1, fp);