Specify levels in terms of 0..1 and not 0..32768.

[c64tapwav] / decode.cpp

diff --git a/decode.cpp b/decode.cpp
index 5d7669af232af9febb802494df77afa021cf9b36..839c2619d91824b0fc49417942c20f6e038690a9 100644 (file)
--- a/decode.cpp
+++ b/decode.cpp
@@ -32,8 +32,8 @@
 #define GAMMA 0.166
 #define ALPHA 1.0
 
-static float hysteresis_upper_limit = 3000.0 / 32768.0;
-static float hysteresis_lower_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;
@@ -51,6 +51,11 @@ static bool output_leveled = false;
 static std::vector<float> 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,
@@ -169,6 +174,7 @@ void output_tap(const std::vector<pulse>& 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' },
@@ -188,11 +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");
@@ -208,7 +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;
 
@@ -217,12 +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':
@@ -235,12 +246,12 @@ void parse_options(int argc, char **argv)
 
                case 'l': {
                        const char *hyststr = strtok(optarg, ": ");
-                       hysteresis_upper_limit = atof(hyststr) / 32768.0;
+                       hysteresis_upper_limit = atof(hyststr);
                        hyststr = strtok(NULL, ": ");
                        if (hyststr == NULL) {
                                hysteresis_lower_limit = -hysteresis_upper_limit;
                        } else {
-                               hysteresis_lower_limit = atof(hyststr) / 32768.0;
+                               hysteresis_lower_limit = atof(hyststr);
                        }
                        break;
                }
@@ -558,7 +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);