shift chroma one bin, to have always three bins per note

2 files changed, 53 insertions, 10 deletions

diff --git a/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp b/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
index 879f8a8c89..7d62253909 100644
--- a/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
+++ b/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
@@ -76,10 +76,11 @@ GetKeyMode::GetKeyMode(Config config) :
 
     // Set C3 (= MIDI #48) as our base:
     // This implies that key = 1 => Cmaj, key = 12 => Bmaj, key = 13 => Cmin, etc.
+    const float centsOffset = -12.0f / kBinsPerOctave * 100; // 3 bins per note, start with the first
     chromaConfig.min =
-        Pitch::getFrequencyForPitch( 48, 0, config.tuningFrequency );
+        Pitch::getFrequencyForPitch( 48, centsOffset, config.tuningFrequency );
     chromaConfig.max =
-        Pitch::getFrequencyForPitch( 96, 0, config.tuningFrequency );
+        Pitch::getFrequencyForPitch( 96, centsOffset, config.tuningFrequency );
 
     chromaConfig.BPO = kBinsPerOctave;
     chromaConfig.CQThresh = 0.0054;
@@ -232,14 +233,11 @@ int GetKeyMode::process(double *pcmData)
     }
 
     for (k = 0; k < kBinsPerOctave; k++) {
-        // The Chromagram has the center of C at bin 0, while the major
-        // and minor profiles have the center of C at 1. We want to have
-        // the correlation for C result also at 1.
-        // To achieve this we have to shift two times:
-        m_majCorr[k] = krumCorr
-            (m_meanHPCP, m_majProfileNorm, k - 2, kBinsPerOctave);
-        m_minCorr[k] = krumCorr
-            (m_meanHPCP, m_minProfileNorm, k - 2, kBinsPerOctave);
+        // The cromagram and the major and minor profiles have the has the
+        // center of C at bin 1. We want to have the correlation for C result
+        // also at 1. To achieve this we have to shift by one:
+        m_majCorr[k] = krumCorr(m_meanHPCP, m_majProfileNorm, (int)k - 1, kBinsPerOctave);
+        m_minCorr[k] = krumCorr(m_meanHPCP, m_minProfileNorm, (int)k - 1, kBinsPerOctave);
     }
 
     // m_MajCorr[1] is C center  1 / 3 + 1 = 1
@@ -314,3 +312,4 @@ double* GetKeyMode::getKeyStrengths() {
 
     return m_keyStrengths;
 }
+
diff --git a/lib/qm-dsp/mixxx-changes.patch b/lib/qm-dsp/mixxx-changes.patch
index 07f921bd41..964e4a39ff 100644
--- a/lib/qm-dsp/mixxx-changes.patch
+++ b/lib/qm-dsp/mixxx-changes.patch
@@ -64,3 +64,47 @@ index 72e5a57..81d8a8e 100644
  extern "C" {
  #endif
 
+diff --git a/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp b/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
+index 879f8a8..7d62253 100644
+--- a/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
++++ b/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
+@@ -76,10 +76,11 @@ GetKeyMode::GetKeyMode(Config config) :
+ 
+     // Set C3 (= MIDI #48) as our base:
+     // This implies that key = 1 => Cmaj, key = 12 => Bmaj, key = 13 => Cmin, etc.
++    const float centsOffset = -12.0f / kBinsPerOctave * 100; // 3 bins per note, start with the first
+     chromaConfig.min =
+-        Pitch::getFrequencyForPitch( 48, 0, config.tuningFrequency );
++        Pitch::getFrequencyForPitch( 48, centsOffset, config.tuningFrequency );
+     chromaConfig.max =
+-        Pitch::getFrequencyForPitch( 96, 0, config.tuningFrequency );
++        Pitch::getFrequencyForPitch( 96, centsOffset, config.tuningFrequency );
+ 
+     chromaConfig.BPO = kBinsPerOctave;
+     chromaConfig.CQThresh = 0.0054;
+@@ -232,14 +233,11 @@ int GetKeyMode::process(double *pcmData)
+     }
+ 
+     for (k = 0; k < kBinsPerOctave; k++) {
+-        // The Chromagram has the center of C at bin 0, while the major
+-        // and minor profiles have the center of C at 1. We want to have
+-        // the correlation for C result also at 1.
+-        // To achieve this we have to shift two times:
+-        m_majCorr[k] = krumCorr
+-            (m_meanHPCP, m_majProfileNorm, k - 2, kBinsPerOctave);
+-        m_minCorr[k] = krumCorr
+-            (m_meanHPCP, m_minProfileNorm, k - 2, kBinsPerOctave);
++        // The cromagram and the major and minor profiles have the has the
++        // center of C at bin 1. We want to have the correlation for C result
++        // also at 1. To achieve this we have to shift by one:
++        m_majCorr[k] = krumCorr(m_meanHPCP, m_majProfileNorm, (int)k - 1, kBinsPerOctave);
++        m_minCorr[k] = krumCorr(m_meanHPCP, m_minProfileNorm, (int)k - 1, kBinsPerOctave);
+     }
+ 
+     // m_MajCorr[1] is C center  1 / 3 + 1 = 1
+@@ -314,3 +312,4 @@ double* GetKeyMode::getKeyStrengths() {
+ 
+     return m_keyStrengths;
+ }
++
+