c@225: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@225: 
c@225: /*
c@225:     QM DSP Library
c@225: 
c@225:     Centre for Digital Music, Queen Mary, University of London.
c@309:     This file 2005-2006 Christian Landone.
c@309: 
c@309:     This program is free software; you can redistribute it and/or
c@309:     modify it under the terms of the GNU General Public License as
c@309:     published by the Free Software Foundation; either version 2 of the
c@309:     License, or (at your option) any later version.  See the file
c@309:     COPYING included with this distribution for more information.
c@225: */
c@225: 
c@225: #include "PhaseVocoder.h"
c@225: #include "dsp/transforms/FFT.h"
c@225: #include <math.h>
c@225: 
c@225: //////////////////////////////////////////////////////////////////////
c@225: // Construction/Destruction
c@225: //////////////////////////////////////////////////////////////////////
c@225: 
c@289: PhaseVocoder::PhaseVocoder(unsigned int n) :
c@289:     m_n(n)
c@225: {
c@289:     m_fft = new FFTReal(m_n);
c@289:     m_realOut = new double[m_n];
c@289:     m_imagOut = new double[m_n];
c@225: }
c@225: 
c@225: PhaseVocoder::~PhaseVocoder()
c@225: {
c@289:     delete [] m_realOut;
c@289:     delete [] m_imagOut;
c@289:     delete m_fft;
c@225: }
c@225: 
c@225: void PhaseVocoder::FFTShift(unsigned int size, double *src)
c@225: {
c@280:     const int hs = size/2;
c@280:     for (int i = 0; i < hs; ++i) {
c@280:         double tmp = src[i];
c@280:         src[i] = src[i + hs];
c@280:         src[i + hs] = tmp;
c@225:     }
c@225: }
c@225: 
c@289: void PhaseVocoder::process(double *src, double *mag, double *theta)
c@225: {
c@289:     FFTShift( m_n, src);
c@289: 	
c@289:     m_fft->process(0, src, m_realOut, m_imagOut);
c@225: 
c@289:     getMagnitude( m_n/2, mag, m_realOut, m_imagOut);
c@289:     getPhase( m_n/2, theta, m_realOut, m_imagOut);
c@225: }
c@225: 
c@225: void PhaseVocoder::getMagnitude(unsigned int size, double *mag, double *real, double *imag)
c@225: {	
c@225:     unsigned int j;
c@225: 
c@225:     for( j = 0; j < size; j++)
c@225:     {
c@225: 	mag[ j ] = sqrt( real[ j ] * real[ j ] + imag[ j ] * imag[ j ]);
c@225:     }
c@225: }
c@225: 
c@225: void PhaseVocoder::getPhase(unsigned int size, double *theta, double *real, double *imag)
c@225: {
c@225:     unsigned int k;
c@225: 
c@225:     // Phase Angle "matlab" style 
c@225:     //Watch out for quadrant mapping  !!!
c@225:     for( k = 0; k < size; k++)
c@225:     {
c@225: 	theta[ k ] = atan2( -imag[ k ], real[ k ]);
c@225:     }	
c@225: }