Add a program to sync up two stereo channels.

[c64tapwav] / decode.cpp

diff --git a/decode.cpp b/decode.cpp
index 798a8729447ab143e51b3fd1bb9f1a11dad572be..e3ec6775161edf854b2522c99dd9eb724e60af27 100644 (file)
--- a/decode.cpp
+++ b/decode.cpp
@@ -125,10 +125,31 @@ int main(int argc, char **argv)
        // Find the flanks.
        int last_bit = -1;
        double last_upflank = -1;
        // Find the flanks.
        int last_bit = -1;
        double last_upflank = -1;

-       int last_max_level = 0;

        for (unsigned i = 0; i < pcm.size(); ++i) {
                int bit = (pcm[i] > 0) ? 1 : 0;
        for (unsigned i = 0; i < pcm.size(); ++i) {
                int bit = (pcm[i] > 0) ? 1 : 0;

-               if (bit == 1 && last_bit == 0 && last_max_level > HYSTERESIS_LIMIT) {
+               if (bit == 1 && last_bit == 0) {
+                       // Check if we ever go up above HYSTERESIS_LIMIT before we dip down again.
+                       bool true_pulse = false;
+                       unsigned j;
+                       int max_level_after = -32768;
+                       for (j = i; j < pcm.size(); ++j) {
+                               max_level_after = std::max<int>(max_level_after, pcm[j]);
+                               if (pcm[j] < 0) break;
+                               if (pcm[j] > HYSTERESIS_LIMIT) {
+                                       true_pulse = true;
+                                       break;
+                               }
+                       }
+
+                       if (!true_pulse) {
+#if 0
+                               fprintf(stderr, "Ignored up-flank at %.6f seconds due to hysteresis (%d < %d).\n",
+                                       double(i) / SAMPLE_RATE, max_level_after, HYSTERESIS_LIMIT);
+#endif
+                               i = j;
+                               continue;
+                       } 
+

                        // up-flank!
                        double t = find_zerocrossing(pcm, i - 1) * (1.0 / SAMPLE_RATE);
                        if (last_upflank > 0) {
                        // up-flank!
                        double t = find_zerocrossing(pcm, i - 1) * (1.0 / SAMPLE_RATE);
                        if (last_upflank > 0) {


@@ -138,9 +159,7 @@ int main(int argc, char **argv)
                                pulses.push_back(p);
                        }
                        last_upflank = t;
                                pulses.push_back(p);
                        }
                        last_upflank = t;

-                       last_max_level = 0;

                }
                }

-               last_max_level = std::max(last_max_level, abs(pcm[i]));

                last_bit = bit;
        }
 
                last_bit = bit;
        }
 


@@ -178,9 +197,11 @@ int main(int argc, char **argv)
                        stddev);
        }
 
                        stddev);
        }
 

+       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;
        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);

                int len = lrintf(cycles / TAP_RESOLUTION);
                if (i > SYNC_PULSE_END && (cycles < 100 || cycles > 800)) {
                        fprintf(stderr, "Cycle with upflank at %.6f was detected at %.0f cycles; misdetect?\n",
                int len = lrintf(cycles / TAP_RESOLUTION);
                if (i > SYNC_PULSE_END && (cycles < 100 || cycles > 800)) {
                        fprintf(stderr, "Cycle with upflank at %.6f was detected at %.0f cycles; misdetect?\n",


@@ -196,6 +217,7 @@ int main(int argc, char **argv)
                        tap_data.push_back(overflow_len >> 16);
                }
        }
                        tap_data.push_back(overflow_len >> 16);
                }
        }

+       fclose(fp);

 
        tap_header hdr;
        memcpy(hdr.identifier, "C64-TAPE-RAW", 12);
 
        tap_header hdr;
        memcpy(hdr.identifier, "C64-TAPE-RAW", 12);