Add pulse analyzer as filter to sample grabber

Author: zuckschwerdt

include/pulse_analyzer.h

@@ -16,6 +16,9 @@
 
 struct r_device;
 
+/// Check the statistics of a pulse data structure and return a summary.
+int pulse_analyzer_check(pulse_data_t *data, int package_type, struct r_device *device);
+
 /// Analyze and print result.
 void pulse_analyzer(pulse_data_t *data, int package_type, struct r_device *device);
 

include/r_private.h

@@ -55,6 +55,7 @@ struct dm_state {
     pulse_data_t    pulse_data;
     pulse_data_t    fsk_pulse_data;
     unsigned frame_event_count;
+    int frame_quality;
     unsigned frame_start_ago;
     unsigned frame_end_ago;
     struct timeval now;

src/pulse_analyzer.c

@@ -201,6 +201,71 @@ static void hexstr_print(hexstr_t *h, FILE *out)
 
 #define TOLERANCE (0.2f) // 20% tolerance should still discern between the pulse widths: 0.33, 0.66, 1.0
 
+/// Check the statistics of a pulse data structure and return a summary.
+int pulse_analyzer_check(pulse_data_t *data, int package_type, r_device *device)
+{
+    (void)package_type;
+    (void)device; // TODO: use device for logging
+
+    if (data->num_pulses == 0) {
+        fprintf(stderr, "Skipping frame without pulses\n");
+        return 0;
+    }
+
+    // Generate pulse period data (pulse + gap, trailing gap)
+    pulse_data_t pulse_periods_pg = {0};
+    pulse_periods_pg.num_pulses   = data->num_pulses;
+    for (unsigned n = 0; n < pulse_periods_pg.num_pulses; ++n) {
+        pulse_periods_pg.pulse[n] = data->pulse[n] + data->gap[n];
+    }
+    // Generate pulse period data (gap + pulse, leading gap)
+    pulse_data_t pulse_periods_gp = {0};
+    pulse_periods_gp.num_pulses   = data->num_pulses;
+    pulse_periods_gp.pulse[0]     = data->pulse[0];
+    for (unsigned n = 1; n < pulse_periods_gp.num_pulses; ++n) {
+        pulse_periods_gp.pulse[n] = data->pulse[n] + data->gap[n - 1];
+    }
+
+    histogram_t hist_pulses     = {0};
+    histogram_t hist_gaps       = {0};
+    histogram_t hist_periods_pg = {0}; // Pulse+Gap periods
+    histogram_t hist_periods_gp = {0}; // Gap+Pulse periods
+    histogram_t hist_timings    = {0};
+
+    // Generate statistics
+    histogram_sum(&hist_pulses, data->pulse, data->num_pulses, TOLERANCE);
+    histogram_sum(&hist_gaps, data->gap, data->num_pulses - 1, TOLERANCE);                               // Leave out last gap (end)
+    histogram_sum(&hist_periods_pg, pulse_periods_pg.pulse, pulse_periods_pg.num_pulses - 1, TOLERANCE); // Leave out last gap (end)
+    histogram_sum(&hist_periods_gp, pulse_periods_gp.pulse, pulse_periods_gp.num_pulses, TOLERANCE);
+    histogram_sum(&hist_timings, data->pulse, data->num_pulses, TOLERANCE);
+    histogram_sum(&hist_timings, data->gap, data->num_pulses, TOLERANCE);
+
+    // Fuse overlapping bins
+    histogram_fuse_bins(&hist_pulses, TOLERANCE);
+    histogram_fuse_bins(&hist_gaps, TOLERANCE);
+    histogram_fuse_bins(&hist_periods_pg, TOLERANCE);
+    histogram_fuse_bins(&hist_timings, TOLERANCE);
+
+    histogram_sort_mean(&hist_pulses); // Easier to work with sorted data
+    histogram_sort_mean(&hist_gaps);
+    if (hist_pulses.bins[0].mean == 0) {
+        histogram_delete_bin(&hist_pulses, 0);
+    } // Remove FSK initial zero-bin
+
+    // Attempt to find a matching modulation
+    if (data->num_pulses == 1) {
+        fprintf(stderr, "Skipping frame with single pulse\n");
+        return 0;
+    }
+    else if (hist_pulses.bins_count == 1 && hist_gaps.bins_count == 1) {
+        fprintf(stderr, "Skipping frame with no data\n");
+        return 0;
+    }
+
+    fprintf(stderr, "Frame with %u bins found\n", hist_pulses.bins_count + hist_gaps.bins_count);
+    return 1;
+}
+
 /// Analyze the statistics of a pulse data structure and print result
 void pulse_analyzer(pulse_data_t *data, int package_type, r_device* device)
 {

src/rtl_433.c

@@ -407,6 +407,7 @@ static void reset_sdr_callback(r_cfg_t *cfg)
     demod->frame_start_ago   = 0;
     demod->frame_end_ago     = 0;
     demod->frame_event_count = 0;
+    demod->frame_quality     = 0;
 
     demod->min_level_auto = 0.0f;
     demod->noise_level    = 0.0f;
@@ -594,6 +595,11 @@ static void sdr_callback(unsigned char *iq_buf, uint32_t len, void *ctx)
                     r_device device = {.log_fn = log_device_handler, .output_ctx = cfg};
                     pulse_analyzer(&demod->pulse_data, package_type, &device);
                 }
+                if (cfg->grab_mode == 4 && p_events == 0) {
+                    r_device device = {.log_fn = log_device_handler, .output_ctx = cfg};
+                    int p_quality   = pulse_analyzer_check(&demod->pulse_data, package_type, &device);
+                    demod->frame_quality = p_quality > demod->frame_quality ? p_quality : demod->frame_quality;
+                }
 
             } else if (package_type == PULSE_DATA_FSK) {
                 calc_rssi_snr(cfg, &demod->fsk_pulse_data);
@@ -621,6 +627,11 @@ static void sdr_callback(unsigned char *iq_buf, uint32_t len, void *ctx)
                     r_device device = {.log_fn = log_device_handler, .output_ctx = cfg};
                     pulse_analyzer(&demod->fsk_pulse_data, package_type, &device);
                 }
+                if (cfg->grab_mode == 4 && p_events == 0) {
+                    r_device device = {.log_fn = log_device_handler, .output_ctx = cfg};
+                    int p_quality   = pulse_analyzer_check(&demod->fsk_pulse_data, package_type, &device);
+                    demod->frame_quality = p_quality > demod->frame_quality ? p_quality : demod->frame_quality;
+                }
             } // if (package_type == ...
             d_events += p_events;
         } // while (package_type)...
@@ -633,16 +644,18 @@ static void sdr_callback(unsigned char *iq_buf, uint32_t len, void *ctx)
             if (demod->samp_grab) {
                 if (cfg->grab_mode == 1
                         || (cfg->grab_mode == 2 && demod->frame_event_count == 0)
-                        || (cfg->grab_mode == 3 && demod->frame_event_count > 0)) {
+                        || (cfg->grab_mode == 3 && demod->frame_event_count > 0)
+                        || (cfg->grab_mode == 4 && demod->frame_event_count == 0 && demod->frame_quality > 0)) {
                     unsigned frame_pad = n_samples / 8; // this could also be a fixed value, e.g. 10000 samples
                     unsigned start_padded = demod->frame_start_ago + frame_pad;
                     unsigned end_padded = demod->frame_end_ago - frame_pad;
                     unsigned len_padded = start_padded - end_padded;
                     samp_grab_write(demod->samp_grab, len_padded, end_padded);
                 }
             }
-            demod->frame_start_ago = 0;
+            demod->frame_start_ago   = 0;
             demod->frame_event_count = 0;
+            demod->frame_quality     = 0;
         }
 
         // dump partial pulse_data for this buffer
@@ -1060,6 +1073,8 @@ static void parse_conf_option(r_cfg_t *cfg, int opt, char *arg)
             cfg->grab_mode = 2;
         else if (strcasecmp(arg, "known") == 0)
             cfg->grab_mode = 3;
+        else if (strcasecmp(arg, "undecoded") == 0)
+            cfg->grab_mode = 4;
         else
             cfg->grab_mode = atobv(arg, 1);
         if (cfg->grab_mode && !cfg->demod->samp_grab)