Merge pull request #13416 from acolombier/fix/remove-signal-scale

fix: remove scaleSignal in waveform analyzer

src/analyzer/analyzerwaveform.h

@@ -18,27 +18,6 @@ class QImage;
 class EngineFilterIIRBase;
 class QSqlDatabase;
 
-inline CSAMPLE scaleSignal(CSAMPLE invalue, FilterIndex index = FilterCount) {
-    if (invalue == 0.0) {
-        return 0;
-    } else if (index == Low || index == Mid) {
-        //return std::pow(invalue, 2 * 0.5);
-        return invalue;
-    } else {
-        return std::pow(invalue, 2.0f * 0.316f);
-    }
-
-    // According to this discussion
-    // https://github.com/mixxxdj/mixxx/issues/6352
-    // it looks like this scaling is done to accentuate
-    // low level information.
-
-    // This scaling can be undone with a function in
-    //  waveform/renderers/waveformrenderersignalbase.h
-    // but arguable it would be better not to do this scaling here at all
-    // and do it (or not) at the waveform renderer side.
-}
-
 struct WaveformStride {
     WaveformStride(double samples, double averageSamples, int stemCount)
             : m_position(0),
@@ -68,13 +47,13 @@ struct WaveformStride {
         for (int i = 0; i < ChannelCount; ++i) {
             WaveformData& datum = *(data + i);
             datum.filtered.all = static_cast<unsigned char>(math_min(255.0,
-                    m_postScaleConversion * scaleSignal(m_overallData[i]) + 0.5));
+                    m_postScaleConversion * m_overallData[i] + 0.5));
             datum.filtered.low = static_cast<unsigned char>(math_min(255.0,
-                    m_postScaleConversion * scaleSignal(m_filteredData[i][Low], Low) + 0.5));
+                    m_postScaleConversion * m_filteredData[i][Low] + 0.5));
             datum.filtered.mid = static_cast<unsigned char>(math_min(255.0,
-                    m_postScaleConversion * scaleSignal(m_filteredData[i][Mid], Mid) + 0.5));
+                    m_postScaleConversion * m_filteredData[i][Mid] + 0.5));
             datum.filtered.high = static_cast<unsigned char>(math_min(255.0,
-                    m_postScaleConversion * scaleSignal(m_filteredData[i][High], High) + 0.5));
+                    m_postScaleConversion * m_filteredData[i][High] + 0.5));
             for (int stemIdx = 0; stemIdx < m_stemCount; stemIdx++) {
                 datum.stems[stemIdx] = static_cast<unsigned char>(math_min(255.0,
                         m_postScaleConversion * m_stemData[i][stemIdx] + 0.5));
@@ -100,26 +79,32 @@ struct WaveformStride {
             for (int i = 0; i < ChannelCount; ++i) {
                 WaveformData& datum = *(data + i);
                 datum.filtered.all = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_averageOverallData[i] / m_averageDivisor) + 0.5));
+                        m_postScaleConversion * m_averageOverallData[i] / m_averageDivisor + 0.5));
                 datum.filtered.low = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_averageFilteredData[i][Low] / m_averageDivisor, Low) + 0.5));
+                        m_postScaleConversion * m_averageFilteredData[i][Low] /
+                                        m_averageDivisor +
+                                0.5));
                 datum.filtered.mid = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_averageFilteredData[i][Mid] / m_averageDivisor, Mid) + 0.5));
+                        m_postScaleConversion * m_averageFilteredData[i][Mid] /
+                                        m_averageDivisor +
+                                0.5));
                 datum.filtered.high = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_averageFilteredData[i][High] / m_averageDivisor, High) + 0.5));
+                        m_postScaleConversion * m_averageFilteredData[i][High] /
+                                        m_averageDivisor +
+                                0.5));
             }
         } else {
             // This is the case if The Overview Waveform has more samples than the detailed waveform
             for (int i = 0; i < ChannelCount; ++i) {
                 WaveformData& datum = *(data + i);
                 datum.filtered.all = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_overallData[i]) + 0.5));
+                        m_postScaleConversion * m_overallData[i] + 0.5));
                 datum.filtered.low = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_filteredData[i][Low], Low) + 0.5));
+                        m_postScaleConversion * m_filteredData[i][Low] + 0.5));
                 datum.filtered.mid = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_filteredData[i][Mid], Mid) + 0.5));
+                        m_postScaleConversion * m_filteredData[i][Mid] + 0.5));
                 datum.filtered.high = static_cast<unsigned char>(math_min(255.0,
-                        m_postScaleConversion * scaleSignal(m_filteredData[i][High], High) + 0.5));
+                        m_postScaleConversion * m_filteredData[i][High] + 0.5));
             }
         }
 

src/waveform/renderers/allshader/waveformrendererhsv.cpp

@@ -138,8 +138,6 @@ void WaveformRendererHSV::paintGL() {
             maxMid[chn] = static_cast<float>(u8maxMid);
             maxHigh[chn] = static_cast<float>(u8maxHigh);
             maxAll[chn] = static_cast<float>(u8maxAll);
-            // Uncomment to undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-            // maxAll[chn] = unscale(u8maxAll);
         }
 
         float total{};

src/waveform/renderers/allshader/waveformrendererrgb.cpp

@@ -168,8 +168,6 @@ void WaveformRendererRGB::paintGL() {
             float maxLow = static_cast<float>(u8maxLow[chn]);
             float maxMid = static_cast<float>(u8maxMid[chn]);
             float maxHigh = static_cast<float>(u8maxHigh[chn]);
-            // Uncomment to undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-            // float maxAllChn[2]{unscale(u8maxAllChn[0]), unscale(u8maxAllChn[1])};
 
             // Calculate the squared magnitude of the maxLow, maxMid and maxHigh values.
             // We take the square root to get the magnitude below.

src/waveform/renderers/allshader/waveformrenderersimple.cpp

@@ -121,9 +121,6 @@ void WaveformRendererSimple::paintGL() {
             for (int i = visualIndexStart + chn; i < visualIndexStop + chn; i += 2) {
                 const WaveformData& waveformData = data[i];
                 const float filteredAll = static_cast<float>(waveformData.filtered.all);
-                // Uncomment to undo scaling with pow(value, 2.0f * 0.316f) done
-                // in analyzerwaveform.h const float filteredAll =
-                // unscale(waveformData.filtered.all);
 
                 max[chn] = math_max(max[chn], filteredAll);
             }

src/waveform/renderers/waveformrenderersignalbase.cpp

@@ -226,13 +226,3 @@ void WaveformRendererSignalBase::getGains(float* pAllGain,
         }
     }
 }
-
-std::span<float, 256> WaveformRendererSignalBase::unscaleTable() {
-    // Table to undo the scaling std::pow(invalue, 2.0f * 0.316f);
-    // done in scaleSignal in analyzerwaveform.h
-    static std::array<float, 256> result;
-    for (int i = 0; i < 256; i++) {
-        result[i] = 255.f * std::pow(static_cast<float>(i) / 255.f, 1.f / 0.632f);
-    }
-    return result;
-}

src/waveform/renderers/waveformrenderersignalbase.h

@@ -27,15 +27,6 @@ class WaveformRendererSignalBase : public WaveformRendererAbstract {
             float* pMidGain,
             float* highGain);
 
-    static std::span<float, 256> unscaleTable();
-    inline float unscale(unsigned char value) {
-        // The all and hi components of the waveform data are scaled with pow(value, 2.0f * 0.316f)
-        // (see analyzerwaveform.h). This function can be used to undo that scaling,
-        // but apparently it is intentional.
-        static const auto table = unscaleTable();
-        return table[value];
-    }
-
   protected:
     ControlProxy* m_pEQEnabled;
     ControlProxy* m_pLowFilterControlObject;

src/waveform/waveformfactory.cpp

@@ -33,6 +33,14 @@ WaveformFactory::VersionClass WaveformFactory::waveformVersionToVersionClass(con
         return VC_REMOVE;
     }
 
+#ifdef __STEM__
+    if (version == WAVEFORM_6_0_VERSION) {
+        // Used in Mixxx 2.6 beta, introducing stem data but later replaced with
+        // the signal scale removal
+        return VC_REMOVE;
+    }
+#endif
+
     // possible a future version
     return VC_KEEP;
 }

src/waveform/waveformfactory.h

@@ -28,9 +28,13 @@ class Waveform;
 #define WAVEFORMSUMMARY_5_DESCRIPTION "WaveformSummary 5.0"
 
 #ifdef __STEM__
-// Used from Mixxx 2.6 with Stem data
-#define WAVEFORM_6_VERSION "Waveform-6.0"
-#define WAVEFORM_6_DESCRIPTION "Waveform 6.0"
+// Used from Mixxx 2.6-pre-alpha with Stem data (6.0) and without
+// analyzer/analyzerwaveform.h:scaleSignal (6.1)
+#define WAVEFORM_6_0_VERSION "Waveform-6.0" // Superseded by 6.1
+#define WAVEFORM_6_VERSION "Waveform-6.1"
+#define WAVEFORMSUMMARY_6_VERSION "WaveformSummary-6.1"
+#define WAVEFORM_6_DESCRIPTION "Waveform 6.1"
+#define WAVEFORMSUMMARY_6_DESCRIPTION "WaveformSummary 6.1"
 
 #define WAVEFORM_CURRENT_VERSION WAVEFORM_6_VERSION
 #define WAVEFORM_CURRENT_DESCRIPTION WAVEFORM_6_DESCRIPTION