3BandFilter.cxx

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/*
 * Copyright (c) 2001-2004 MUSIC TECHNOLOGY GROUP (MTG)
 *                         UNIVERSITAT POMPEU FABRA
 *
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "3BandFilter.hxx"
#include "ProcessingFactory.hxx"

namespace CLAM
{
namespace Hidden
{
        static const char * metadata[] = {
                "key", "ThreeBandFilter",
                "category", "Spectral Transformations",
                "description", "ThreeBandFilter",
                0
        };
        static FactoryRegistrator<ProcessingFactory, ThreeBandFilter> reg = metadata;
}


bool ThreeBandFilter::Do(const Spectrum& in, Spectrum& out)
{
        if ( !mConfig.GetPreserveOuts() )
        {
                out = in; //TODO big cludge for streaming
        }
        
        DataArray& oMag = out.GetMagBuffer();
        
        int spectrumSize = in.GetSize();
        
        TData spectralResolution = spectrumSize/in.GetSpectralRange();
        
        int lowCutoff = Round(mLowCutoffFreqCtl.GetLastValue()* spectralResolution);
        int highCutoff = Round(mHighCutoffFreqCtl.GetLastValue()* spectralResolution);

        //note: control is supposed to be sent as dB's
        TData lowGain =         log2lin(mLowGainCtl.GetLastValue());
        TData midGain =         log2lin(mMidGainCtl.GetLastValue());
        TData highGain =        log2lin(mHighGainCtl.GetLastValue());
        
        TData currentGain = lowGain;
        for(int i = 0; i<spectrumSize; i++)
        {
                if(i>highCutoff) 
                        currentGain = highGain;
                else if(i==highCutoff)
                        currentGain = (highGain+midGain)*0.5; //implementing small rolloff to avoid Gibbs effect
                else if(i>lowCutoff) 
                        currentGain = midGain;
                else if(i==lowCutoff)
                        currentGain = (lowGain+midGain)*0.5; //implementing small rolloff to avoid Gibbs effect 
                oMag[i] *= currentGain;
        }
        return true;
}


}