fft_result.cc

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/*
    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];
}