Chris@35: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@35: 
Chris@42: /*
Chris@42:     Tipic
Chris@42: 
Chris@42:     Centre for Digital Music, Queen Mary, University of London.
Chris@42: 
Chris@42:     This program is free software; you can redistribute it and/or
Chris@42:     modify it under the terms of the GNU General Public License as
Chris@42:     published by the Free Software Foundation; either version 2 of the
Chris@42:     License, or (at your option) any later version.  See the file
Chris@42:     COPYING included with this distribution for more information.
Chris@42: */
Chris@42: 
Chris@35: #include "FeatureDownsample.h"
Chris@35: 
Chris@42: #include "dsp/signalconditioning/Filter.h"
Chris@42: #include "base/Window.h"
Chris@42: #include "maths/MathUtilities.h"
Chris@35: 
Chris@35: #include <stdexcept>
Chris@35: 
Chris@35: using namespace std;
Chris@35: 
Chris@35: FeatureDownsample::FeatureDownsample(Parameters params) :
Chris@35:     m_params(params)
Chris@35: {
Chris@35:     if (params.downsampleFactor < 2 || params.windowLength < 2) {
Chris@35: 	throw invalid_argument
Chris@35: 	    ("Expected downsampleFactor and windowLength each to be at least 2");
Chris@35:     }
Chris@35: 
Chris@35:     // Our windows are periodic rather than symmetric, but we want a
Chris@35:     // symmetric window here
Chris@37:     Window<double> w(HanningWindow, params.windowLength + 1);
Chris@37:     vector<double> wdat(w.getWindowData());;
Chris@37:     vector<double> wd(wdat.begin()+1, wdat.end());
Chris@35: 
Chris@36:     double divisor = 0.0;
Chris@36:     for (auto x: wd) divisor += x;
Chris@36:     for (auto &x: wd) x /= divisor;
Chris@36: 
Chris@35:     // FIR filter
Chris@35:     for (int i = 0; i < m_params.featureSize; ++i) {
Chris@35: 	m_filters.push_back(new Filter({ {}, wd }));
Chris@35:     }
Chris@35: 
Chris@36:     m_toNext = 1;
Chris@36:     m_toDrop = m_params.windowLength / 2;
Chris@36:     m_inCount = 0;
Chris@36:     m_outCount = 0;
Chris@35: }
Chris@35: 
Chris@35: FeatureDownsample::~FeatureDownsample()
Chris@35: {
Chris@35:     for (auto &f: m_filters) delete f;
Chris@35: }
Chris@35: 
Chris@35: void
Chris@35: FeatureDownsample::reset()
Chris@35: {
Chris@35:     for (auto &f: m_filters) f->reset();
Chris@36:     m_toNext = 1;
Chris@36:     m_toDrop = m_params.windowLength / 2;
Chris@36:     m_inCount = 0;
Chris@36:     m_outCount = 0;
Chris@35: }
Chris@35: 
Chris@35: RealBlock
Chris@35: FeatureDownsample::process(const RealBlock &in)
Chris@35: {
Chris@36:     RealBlock out;
Chris@35:     
Chris@35:     for (const auto &col: in) {
Chris@35: 	RealColumn outcol;
Chris@36: 	if (m_toDrop > 0) {
Chris@36: 	    --m_toDrop;
Chris@36: 	} else {
Chris@36: 	    --m_toNext;
Chris@36: 	}
Chris@35: 	for (int i = 0; i < m_params.featureSize; ++i) {
Chris@35: 	    double val = 0.0;
Chris@35: 	    m_filters[i]->process(&col[i], &val, 1);
Chris@35: 	    if (m_toNext == 0) {
Chris@35: 		outcol.push_back(val);
Chris@35: 	    }
Chris@35: 	}
Chris@35: 	if (m_toNext == 0) {
Chris@42: 	    out.push_back(MathUtilities::normaliseLp
Chris@37: 			  (outcol, m_params.normP, m_params.normThresh));
Chris@35: 	    m_toNext = m_params.downsampleFactor;
Chris@36: 	    ++m_outCount;
Chris@35: 	}
Chris@36: 	++m_inCount;
Chris@36:     }
Chris@36:     
Chris@36:     return out;
Chris@36: }
Chris@36: 
Chris@36: RealBlock
Chris@36: FeatureDownsample::getRemainingOutput()
Chris@36: {
Chris@36:     RealBlock pad(m_params.windowLength, RealColumn(m_params.featureSize, 0.0));
Chris@36:     RealBlock tail = process(pad);
Chris@36:     int expected = m_inCount / m_params.downsampleFactor;
Chris@36:     RealBlock out;
Chris@36:     for (int i = 0;
Chris@36: 	 m_outCount < expected && i < int(tail.size());
Chris@36: 	 ++i, ++m_outCount) {
Chris@42: 	out.push_back(MathUtilities::normaliseLp
Chris@37: 		      (tail[i], m_params.normP, m_params.normThresh));
Chris@35:     }
Chris@35:     return out;
Chris@35: }
Chris@35: 
Chris@36: