X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Faudioscopes%2Fffttools.h;h=26cee848288bfcca5015de29da86389d50bc8182;hb=6ee97189c48f7e8271aa04fb34b650c1ae1037d2;hp=acc8e6ee2f65f9e4f70540b372b60fb442931813;hpb=d445699b4be47caffd2604c669088571696763b9;p=kdenlive

diff --git a/src/audioscopes/ffttools.h b/src/audioscopes/ffttools.h
index acc8e6ee..26cee848 100644
--- a/src/audioscopes/ffttools.h
+++ b/src/audioscopes/ffttools.h
@@ -12,11 +12,14 @@
 #define FFTTOOLS_H
 
 #include <QVector>
+#include <QHash>
+#include "kiss_fft/tools/kiss_fftr.h"
 
 class FFTTools
 {
 public:
     FFTTools();
+    ~FFTTools();
 
     enum WindowType { Window_Rect, Window_Triangle, Window_Hamming };
 
@@ -33,7 +36,46 @@ public:
           default is 0)
         * Nothing for the Hamming window
     */
-    static const QVector<float> window(WindowType windowType, const int size, const float param);
+    static const QVector<float> window(const WindowType windowType, const int size, const float param = 0);
+
+    static const QString windowSignature(const WindowType windowType, const int size, const float param = 0);
+
+    /** Returns a signature for a kiss_fft configuration
+        used as a hash in the cache */
+    static const QString cfgSignature(const int size);
+
+    /** Calculates the Fourier Tranformation of the input audio frame.
+        The resulting values will be given in relative dezibel: The maximum power is 0 dB, lower powers have
+        negative dB values.
+        * audioFrame: Interleaved format with #numChannels channels
+        * freqSpectrum: Array pointer to write the data into
+        * windowSize must be divisible by 2,
+        * freqSpectrum has to be of size windowSize/2
+        For windowType and param see the FFTTools::window() function above.
+    */
+    void fftNormalized(const QVector<int16_t> audioFrame, const uint channel, const uint numChannels, float *freqSpectrum,
+                       const WindowType windowType, const uint windowSize, const float param = 0);
+
+
+    /** This is linear interpolation with the special property that it preserves peaks, which is required
+        for e.g. showing correct Decibel values (where the peak values are of interest because of clipping which
+        may occur for too strong frequencies; The lower values are smeared by the window function anyway).
+        Consider f = {0, 100, 0}
+                 x = {0.5,  1.5}: With default linear interpolation x0 and x1 would both be mapped to 50.
+        This function maps x1 (the first position after the peak) to 100.
+
+        @param in           The source vector containing the data
+        @param targetSize   Number of interpolation nodes between ...
+        @param left         the left array index in the in-vector and ...
+        @param right        the right array index (both inclusive).
+        @param fill         If right lies outside of the array bounds (which is perfectly fine here) then this value
+                            will be used for filling the missing information.
+        */
+    static const QVector<float> interpolatePeakPreserving(const QVector<float> in, const uint targetSize, uint left = 0, uint right = 0, float fill = 0.0);
+
+private:
+    QHash<QString, kiss_fftr_cfg> m_fftCfgs; // FFT cfg cache
+    QHash<QString, QVector<float> > m_windowFunctions; // Window function cache
 
 };