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fft_result.cc

/*
    Copyright (C) 2006 Paul Davis
      Written by Sampo Savolainen

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <fft_result.h>
#include <fft_graph.h>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>

#include <iostream>

using namespace std;

FFTResult::FFTResult(FFTGraph *graph, Gdk::Color color, string trackname)
{
      _graph = graph;
      
      _windowSize = _graph->windowSize();
      _dataSize   = _windowSize / 2;

      _averages = 0;

      _data_avg = (float *) malloc(sizeof(float) * _dataSize);
      memset(_data_avg,0,sizeof(float) * _dataSize);

      _data_min = (float *) malloc(sizeof(float) * _dataSize);
      _data_max = (float *) malloc(sizeof(float) * _dataSize);

      for (int i = 0; i < _dataSize; i++) {
            _data_min[i] = FLT_MAX;
            _data_max[i] = FLT_MIN;
      }

      _color     = color;
      _trackname = trackname;
}

void
FFTResult::analyzeWindow(float *window)
{
      float *_hanning = _graph->_hanning;
      float *_in = _graph->_in;
      float *_out = _graph->_out;

      int i;
      // Copy the data and apply the hanning window
      for (i = 0; i < _windowSize; i++) {
            _in[i] = window[ i ] * _hanning[ i ];
      }

      fftwf_execute(_graph->_plan);

      float b = _out[0] * _out[0];

      _data_avg[0] += b;
      if (b < _data_min[0]) _data_min[0] = b;
      if (b > _data_max[0]) _data_max[0] = b;
      
      for (i=1; i < _dataSize - 1; i++) { // TODO: check with Jesse whether this is really correct
            b = (_out[i] * _out[i]);

            _data_avg[i] += b;  // + (_out[_windowSize-i] * _out[_windowSize-i]);, TODO: thanks to Stefan Kost
            
            if (_data_min[i] > b)  _data_min[i] = b;
            if (_data_max[i] < b ) _data_max[i] = b;
      }


      _averages++;
}

void
FFTResult::finalize()
{
      if (_averages == 0) {
            _minimum = 0.0;
            _maximum = 0.0;
            return;
      }

      // Average & scale
      for (int i = 0; i < _dataSize; i++) {
            _data_avg[i] /= _averages;
            _data_avg[i]  = 10.0f * log10f(_data_avg[i]); 

            _data_min[i]  = 10.0f * log10f(_data_min[i]); 
            if (_data_min[i] < -10000.0f) {
                  _data_min[i] = -10000.0f;
            }
            _data_max[i]  = 10.0f * log10f(_data_max[i]); 
      }

      // find min & max
      _minimum = _maximum = _data_avg[0];
      
      for (int i = 1; i < _dataSize; i++) {
            if (_data_avg[i] < _minimum        && !isinf(_data_avg[i])) {
                  _minimum = _data_avg[i];
            } else if (_data_avg[i] > _maximum && !isinf(_data_avg[i])) {
                  _maximum = _data_avg[i];
            }
      }

      _averages = 0;
}

FFTResult::~FFTResult()
{
      free(_data_avg);
      free(_data_min);
      free(_data_max);
}


float
FFTResult::avgAt(int x)
{
      if (x < 0 || x>= _dataSize)
            return 0.0f;

      return _data_avg[x];
}

float
FFTResult::minAt(int x)
{
      if (x < 0 || x>= _dataSize)
            return 0.0f;

      return _data_min[x];
}

float
FFTResult::maxAt(int x)
{
      if (x < 0 || x>= _dataSize)
            return 0.0f;

      return _data_max[x];
}


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