dont unscale, apparently its intentional

src/analyzer/analyzerwaveform.h

@@ -27,9 +27,15 @@ inline CSAMPLE scaleSignal(CSAMPLE invalue, FilterIndex index = FilterCount) {
         return std::pow(invalue, 2.0f * 0.316f);
     }
 
-    // TODO this function needs an explanation of why this scaling is applied.
-    // Note that in the allshader waveform-renderers, this scaling is undone for
-    // the filtered.all band.
+    // 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 {

src/waveform/renderers/allshader/waveformrendererhsv.cpp

@@ -129,8 +129,9 @@ void WaveformRendererHSV::paintGL() {
             maxLow[chn] = static_cast<float>(u8maxLow);
             maxMid[chn] = static_cast<float>(u8maxMid);
             maxHigh[chn] = static_cast<float>(u8maxHigh);
-            // Undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-            maxAll[chn] = unscale(u8maxAll);
+            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/waveformrendererlrrgb.cpp

@@ -136,8 +136,9 @@ void WaveformRendererLRRGB::paintGL() {
             float maxLow = static_cast<float>(u8maxLow);
             float maxMid = static_cast<float>(u8maxMid);
             float maxHigh = static_cast<float>(u8maxHigh);
-            // Undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-            float maxAll = unscale(u8maxAll);
+            float maxAll = static_cast<float>(u8maxAll);
+            // Uncomment to undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
+            // float maxAll = unscale(u8maxAll);
 
             // 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/waveformrendererrgb.cpp

@@ -138,8 +138,9 @@ void WaveformRendererRGB::paintGL() {
         float maxLow = static_cast<float>(u8maxLow);
         float maxMid = static_cast<float>(u8maxMid);
         float maxHigh = static_cast<float>(u8maxHigh);
-        // Undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-        float maxAllChn[2]{unscale(u8maxAllChn[0]), unscale(u8maxAllChn[1])};
+        float maxAllChn[2]{static_cast<float>(u8maxAllChn[0]), static_cast<float>(u8maxAllChn[1])};
+        // 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

@@ -119,8 +119,10 @@ void WaveformRendererSimple::paintGL() {
             // data is interleaved left / right
             for (int i = visualIndexStart + chn; i < visualIndexStop + chn; i += 2) {
                 const WaveformData& waveformData = data[i];
-                // Undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
-                const float filteredAll = unscale(waveformData.filtered.all);
+                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.h

@@ -23,9 +23,11 @@ class WaveformRendererSignalBase : public WaveformRendererAbstract {
     void getGains(float* pAllGain, float* pLowGain, float* pMidGain,
                   float* highGain);
 
-    // To undo scaling with pow(value, 2.0f * 0.316f) done in analyzerwaveform.h
     static float* 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 float* table = unscaleTable();
         return table[value];
     }