Report convolution code error score.

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

src/audiowmark.cc

@@ -988,16 +988,17 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern)
     assert (soft_bit_vec.size() >= conv_code_size (Params::payload_size));
     soft_bit_vec.resize (conv_code_size (Params::payload_size));
 
-    vector<int> bit_vec = conv_decode_soft (randomize_bit_order (soft_bit_vec, /* encode */ false));
+    float decode_error = 0;
+    vector<int> bit_vec = conv_decode_soft (randomize_bit_order (soft_bit_vec, /* encode */ false), &decode_error);
 
     if (sync_score.index)
       {
         const int seconds = lrint (sync_score.index / wav_data.mix_freq());
-        printf ("pattern %2d:%02d %s %.3f\n", seconds / 60, seconds % 60, bit_vec_to_str (bit_vec).c_str(), sync_score.quality);
+        printf ("pattern %2d:%02d %s %.3f %.3f\n", seconds / 60, seconds % 60, bit_vec_to_str (bit_vec).c_str(), sync_score.quality, decode_error);
       }
     else /* this is the combined pattern "all" */
       {
-        printf ("pattern   all %s %.3f\n", bit_vec_to_str (bit_vec).c_str(), sync_score.quality);
+        printf ("pattern   all %s %.3f %.3f\n", bit_vec_to_str (bit_vec).c_str(), sync_score.quality, decode_error);
       }
 
     if (!orig_pattern.empty())

src/convcode.cc

 #include "utils.hh"
+#include "convcode.hh"
 
 #include <array>
 #include <algorithm>
@@ -74,7 +75,7 @@ conv_encode (const vector<int>& in_bits)
 
 /* decode using viterbi algorithm */
 vector<int>
-conv_decode_soft (const vector<float>& coded_bits)
+conv_decode_soft (const vector<float>& coded_bits, float *error_out)
 {
   vector<int> decoded_bits;
 
@@ -141,6 +142,8 @@ conv_decode_soft (const vector<float>& coded_bits)
     }
 
   unsigned int state = 0;
+  if (error_out)
+    *error_out = error_count.back()[state].delta / coded_bits.size();
   for (size_t idx = error_count.size() - 1; idx > 0; idx--)
     {
       decoded_bits.push_back (error_count[idx][state].bit);

src/convcode.hh

@@ -7,6 +7,6 @@
 size_t           conv_code_size (size_t msg_size);
 std::vector<int> conv_encode (const std::vector<int>& in_bits);
 std::vector<int> conv_decode_hard (const std::vector<int>& coded_bits);
-std::vector<int> conv_decode_soft (const std::vector<float>& coded_bits);
+std::vector<int> conv_decode_soft (const std::vector<float>& coded_bits, float *error_out = nullptr);
 
 #endif /* AUDIOWMARK_CONV_CODE_HH */