first performance version

1 files changed, 45 insertions, 0 deletions

diff --git a/07_performance/src/FFTOctaveAnalyzer.h b/07_performance/src/FFTOctaveAnalyzer.h
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+++ b/07_performance/src/FFTOctaveAnalyzer.h
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+
+#ifndef _FFTANALYZER
+#define _FFTANALYZER
+
+#ifndef M_PI
+#define	M_PI		3.14159265358979323846  /* pi */
+#endif
+
+
+class FFTOctaveAnalyzer {
+	
+public:
+	
+	//FFT fft;  // a reference to the FFT instance
+	
+	float samplingRate; // sampling rate in Hz (needed to calculate frequency spans)
+	int nSpectrum; // number of spectrum bins in the fft
+	int nAverages; // number of averaging bins here
+	int nAveragesPerOctave; // number of averages per octave as requested by user
+	float spectrumFrequencySpan; // the "width" of an fft spectrum bin in Hz
+	float firstOctaveFrequency; // the "top" of the first averaging bin here in Hz
+	float averageFrequencyIncrement; // the root-of-two multiplier between averaging bin frequencies
+	float * averages; // the actual averages
+	float * peaks; // peaks of the averages, aka "maxAverages" in other implementations
+	int * peakHoldTimes; // how long to hold THIS peak meter?  decay if == 0
+	int peakHoldTime; // how long do we hold peaks? (in fft frames)
+	float peakDecayRate; // how quickly the peaks decay:  0f=instantly .. 1f=not at all
+	int * spe2avg; // the mapping between spectrum[] indices and averages[] indices
+	// the fft's log equalizer() is no longer of any use (it would be nonsense to log scale
+	// the spectrum values into log-sized average bins) so here's a quick-and-dirty linear
+	// equalizer instead:
+	float linearEQSlope; // the rate of linear eq
+	float linearEQIntercept; // the base linear scaling used at the first averaging bin
+	// the formula is:  spectrum[i] * (linearEQIntercept + i * linearEQSlope)
+	// so.. note that clever use of it can also provide a "gain" control of sorts
+	// (fe: set intercept to 2f and slope to 0f to double gain)
+	
+	void setup(float samplingRate, int nBandsInTheFFT, int nAveragesPerOctave);
+	
+	void calculate(float * fftData);
+	
+};
+
+
+#endif