# HG changeset patch
# User Chris Cannam
# Date 1341691597 -3600
# Node ID 44bb93cae2882d8f32cb5a7f45c01f221d55f490
# Parent  a15d8c89a36e701e3fe58e955905f8de6ce92331
Change peak-to-next-peak ratio to a difference (because difference of peaks in log values don't vary with signal amplification)

diff -r a15d8c89a36e -r 44bb93cae288 CepstrumPitchTracker.cpp
--- a/CepstrumPitchTracker.cpp	Thu Jul 05 21:54:50 2012 +0100
+++ b/CepstrumPitchTracker.cpp	Sat Jul 07 21:06:37 2012 +0100
@@ -530,12 +530,6 @@
     filter(rawcep, data);
     delete[] rawcep;
 
-    double abstot = 0.0;
-
-    for (int i = 0; i < n; ++i) {
-	abstot += fabs(data[i]);
-    }
-
     double maxval = 0.0;
     int maxbin = -1;
 
@@ -566,7 +560,7 @@
 
     double confidence = 0.0;
     if (nextPeakVal != 0.0) {
-        confidence = ((maxval / nextPeakVal) - 1.0) / 4.0;
+        confidence = (maxval - nextPeakVal) / 200.0;
         if (confidence > 1.0) confidence = 1.0;
     }
 
diff -r a15d8c89a36e -r 44bb93cae288 SimpleCepstrum.cpp
--- a/SimpleCepstrum.cpp	Thu Jul 05 21:54:50 2012 +0100
+++ b/SimpleCepstrum.cpp	Sat Jul 07 21:06:37 2012 +0100
@@ -306,9 +306,9 @@
     outputs.push_back(d);
 
     d.identifier = "peak_to_second_peak";
-    d.name = "Peak to second-peak ratio";
+    d.name = "Peak to second-peak difference";
     d.unit = "";
-    d.description = "Return the ratio of the value found in the peak bin within the specified range of the cepstrum, to the value found in the next highest peak";
+    d.description = "Return the difference between the value found in the peak bin within the specified range of the cepstrum, and that found in the next highest peak";
     m_pkoOutput = n++;
     outputs.push_back(d);
 
@@ -616,7 +616,7 @@
 
     Feature pko;
     if (nextPeakVal != 0.0) {
-        pko.values.push_back(maxval / nextPeakVal);
+        pko.values.push_back(maxval - nextPeakVal);
     } else {
         pko.values.push_back(0.0);
     }