From 3d6f915b75b1c8c0bf53abeef3e29fc36da7ea40 Mon Sep 17 00:00:00 2001
From: Ahmet Inan <xdsopl@googlemail.com>
Date: Sat, 13 Dec 2014 20:31:06 +0100
Subject: [PATCH] improved calibration header detection

"gray" area doesn't work very well with the calibration detection code
---
 app/src/main/rs/calibration_detector.rsh | 9 ++++++---
 app/src/main/rs/decoder.rs               | 9 ++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/app/src/main/rs/calibration_detector.rsh b/app/src/main/rs/calibration_detector.rsh
index 9b926e5..87045bb 100644
--- a/app/src/main/rs/calibration_detector.rsh
+++ b/app/src/main/rs/calibration_detector.rsh
@@ -20,7 +20,7 @@ limitations under the License.
 #include "constants.rsh"
 #include "state.rsh"
 
-static int calibration_detected(float dat_value, int dat_active, int cnt_active, int cnt_quantized)
+static int calibration_detected(float dat_value, float dat_amp, float cnt_amp, int cnt_quantized)
 {
     static int progress, countdown;
     static int leader_counter, break_counter;
@@ -28,6 +28,9 @@ static int calibration_detected(float dat_value, int dat_active, int cnt_active,
     progress = countdown ? progress : 0;
     countdown -= !!countdown;
 
+    int cnt_active = dat_amp < cnt_amp;
+    int dat_active = !cnt_active;
+
     int leader_quantized = round(filter(&leader_lowpass, dat_value));
     int leader_level = dat_active && leader_quantized == 0;
     int leader_pulse = !leader_level && leader_counter >= leader_length;
@@ -98,9 +101,9 @@ static int calibration_detected(float dat_value, int dat_active, int cnt_active,
     return -1;
 }
 
-static int calibration_detector(float dat_value, int dat_active, int cnt_active, int cnt_quantized)
+static int calibration_detector(float dat_value, float dat_amp, float cnt_amp, int cnt_quantized)
 {
-    switch (calibration_detected(dat_value, dat_active, cnt_active, cnt_quantized)) {
+    switch (calibration_detected(dat_value, dat_amp, cnt_amp, cnt_quantized)) {
         case 0x88:
             return mode_robot36;
         case 0x0c:
diff --git a/app/src/main/rs/decoder.rs b/app/src/main/rs/decoder.rs
index 6c3411a..eef1e7d 100644
--- a/app/src/main/rs/decoder.rs
+++ b/app/src/main/rs/decoder.rs
@@ -177,8 +177,11 @@ void decode(int samples) {
         float cnt_value = demodulate(&cnt_fmd, cnt_baseband);
         float dat_value = demodulate(&dat_fmd, dat_baseband);
 
-        int cnt_active = cabs(dat_baseband) < 4.0f * cabs(cnt_baseband);
-        int dat_active = cabs(cnt_baseband) < 4.0f * cabs(dat_baseband);
+        float cnt_amp = cabs(cnt_baseband);
+        float dat_amp = cabs(dat_baseband);
+
+        int cnt_active = dat_amp < 4.0f * cnt_amp;
+        int dat_active = cnt_amp < 4.0f * dat_amp;
         uchar cnt_level = save_cnt && cnt_active ? 127.5f - 127.5f * cnt_value : 0.0f;
         uchar dat_level = save_dat && dat_active ? 127.5f + 127.5f * dat_value : 0.0f;
         value_buffer[hpos + prev_hpos] = cnt_level | dat_level;
@@ -191,7 +194,7 @@ void decode(int samples) {
         sync_counter = sync_level ? sync_counter + 1 : 0;
 
         if (*current_mode != mode_debug) {
-            int detected_mode = calibration_detector(dat_value, dat_active, cnt_active, cnt_quantized);
+            int detected_mode = calibration_detector(dat_value, dat_amp, cnt_amp, cnt_quantized);
             if (detected_mode >= 0) {
                 free_running = 0;
                 reset_buffer();