Use double precision for FS (sample rate)

This fixes a rounding error when using source sample rates not divisible by 8
daschuer · May 12, 2019 · 957aed5 · 957aed5
1 parent 2c81fb9
commit 957aed5
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Showing 5 changed files with 8 additions and 8 deletions.
diff --git a/lib/qm-dsp/dsp/chromagram/Chromagram.cpp b/lib/qm-dsp/dsp/chromagram/Chromagram.cpp
@@ -44,7 +44,7 @@ int Chromagram::initialise( ChromaConfig Config )
 
     // Populate CQ config structure with parameters
     // inherited from the Chroma config
-    ConstantQConfig.FS	 = Config.FS;
+    ConstantQConfig.FS = Config.FS;
     ConstantQConfig.min = m_FMin;
     ConstantQConfig.max = m_FMax;
     ConstantQConfig.BPO = m_BPO;

diff --git a/lib/qm-dsp/dsp/chromagram/Chromagram.h b/lib/qm-dsp/dsp/chromagram/Chromagram.h
@@ -21,7 +21,7 @@
 #include "ConstantQ.h"
 
 struct ChromaConfig{
-    unsigned int FS;
+    double FS;
     double min;
     double max;
     unsigned int BPO;

diff --git a/lib/qm-dsp/dsp/chromagram/ConstantQ.cpp b/lib/qm-dsp/dsp/chromagram/ConstantQ.cpp
@@ -125,8 +125,9 @@ void ConstantQ::sparsekernel()
             hammingWindowIm[u] = 0;
         }
 
-	// Computing a hamming window
-	const unsigned hammingLength = (int) ceil( m_dQ * m_FS / ( m_FMin * pow(2,((double)(k))/(double)m_BPO)));
+        // Computing a hamming window
+        const unsigned hammingLength = (int) ceil(
+                m_dQ * m_FS / (m_FMin * pow(2, (double)k / (double)m_BPO)));
 
         unsigned origin = m_FFTLength/2 - hammingLength/2;
 

diff --git a/lib/qm-dsp/dsp/chromagram/ConstantQ.h b/lib/qm-dsp/dsp/chromagram/ConstantQ.h
@@ -21,7 +21,7 @@
 #include "maths/MathUtilities.h"
 
 struct CQConfig{
-    unsigned int FS;   // samplerate
+    double FS;   // samplerate
     double min;        // minimum frequency
     double max;        // maximum frequency
     unsigned int BPO;  // bins per octave
@@ -58,7 +58,7 @@ class ConstantQ {
     void deInitialise();
 
     double* m_CQdata;
-    unsigned int m_FS;
+    double m_FS;
     double m_FMin;
     double m_FMax;
     double m_dQ;

diff --git a/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp b/lib/qm-dsp/dsp/keydetection/GetKeyMode.cpp
@@ -60,8 +60,7 @@ GetKeyMode::GetKeyMode( int sampleRate, float tuningFrequency,
 
     // Chromagram configuration parameters
     m_ChromaConfig.normalise = MathUtilities::NormaliseUnitMax;
-    m_ChromaConfig.FS = lrint(sampleRate/(double)m_DecimationFactor);
-    if (m_ChromaConfig.FS < 1) m_ChromaConfig.FS = 1;
+    m_ChromaConfig.FS = sampleRate/(double)m_DecimationFactor;
 
     // Set C3 (= MIDI #48) as our base:
     // This implies that key = 1 => Cmaj, key = 12 => Bmaj, key = 13 => Cmin, etc.