Merge sync finder / speed detection raw bit quality function.

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

src/syncfinder.cc

@@ -89,6 +89,28 @@ SyncFinder::normalize_sync_quality (double raw_quality)
   return raw_quality / min (Params::water_delta, 0.080) / 2.9;
 }
 
+double
+SyncFinder::bit_quality (float umag, float dmag, int bit)
+{
+  const int expect_data_bit = bit & 1; /* expect 010101 */
+
+  /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
+  double raw_bit;
+  if (umag == 0 || dmag == 0)
+    {
+      raw_bit = 0;
+    }
+  else if (umag < dmag)
+    {
+      raw_bit = 1 - umag / dmag;
+    }
+  else
+    {
+      raw_bit = dmag / umag - 1;
+    }
+  return expect_data_bit ? raw_bit : -raw_bit;
+}
+
 double
 SyncFinder::sync_decode (const WavData& wav_data, const size_t start_frame,
                          const vector<float>& fft_out_db,
@@ -118,24 +140,7 @@ SyncFinder::sync_decode (const WavData& wav_data, const size_t start_frame,
               frame_bit_count++;
             }
         }
-      /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
-      double raw_bit;
-      if (umag == 0 || dmag == 0)
-        {
-          raw_bit = 0;
-        }
-      else if (umag < dmag)
-        {
-          raw_bit = 1 - umag / dmag;
-        }
-      else
-        {
-          raw_bit = dmag / umag - 1;
-        }
-
-      const int expect_data_bit = bit & 1; /* expect 010101 */
-      const double q = expect_data_bit ? raw_bit : -raw_bit;
-      sync_quality += q * frame_bit_count;
+      sync_quality += bit_quality (umag, dmag, bit) * frame_bit_count;
       bit_count += frame_bit_count;
     }
   if (bit_count)

src/syncfinder.hh

@@ -99,6 +99,8 @@ private:
 public:
   std::vector<Score> search (const WavData& wav_data, Mode mode);
   std::vector<std::vector<FrameBit>> get_sync_bits (const WavData& wav_data, Mode mode);
+
+  static double bit_quality (float umag, float dmag, int bit);
 private:
   void sync_fft (const WavData& wav_data,
                  size_t index,

src/wmspeed.cc

@@ -349,23 +349,7 @@ SpeedSync::compare (double relative_speed)
         {
           const auto& bv = bit_values[bit];
 
-          /* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
-          double raw_bit;
-          if (bv.umag == 0 || bv.dmag == 0)
-            {
-              raw_bit = 0;
-            }
-          else if (bv.umag < bv.dmag)
-            {
-              raw_bit = 1 - bv.umag / bv.dmag;
-            }
-          else
-            {
-              raw_bit = bv.dmag / bv.umag - 1;
-            }
-          const int expect_data_bit = bit & 1; /* expect 010101 */
-          const double q = expect_data_bit ? raw_bit : -raw_bit;
-          sync_quality += q * bv.count;
+          sync_quality += SyncFinder::bit_quality (bv.umag, bv.dmag, bit) * bv.count;
           bit_count += bv.count;
         }
       if (bit_count)
@@ -373,7 +357,7 @@ SpeedSync::compare (double relative_speed)
           sync_quality /= bit_count;
           sync_quality = fabs (sync_quality);
           //sync_quality = fabs (sync_finder.normalize_sync_quality (sync_quality));
-          //printf ("%d %f\n", offset, fabs (sync_quality));
+
           if (sync_quality > best_score.quality)
             {
               best_score.quality = sync_quality;