cannam@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
cannam@0: 
cannam@0: /*
cannam@0:     QM DSP Library
cannam@0: 
cannam@0:     Centre for Digital Music, Queen Mary, University of London.
Chris@84:     This file 2005-2006 Christian Landone.
Chris@84: 
Chris@84:     This program is free software; you can redistribute it and/or
Chris@84:     modify it under the terms of the GNU General Public License as
Chris@84:     published by the Free Software Foundation; either version 2 of the
Chris@84:     License, or (at your option) any later version.  See the file
Chris@84:     COPYING included with this distribution for more information.
cannam@0: */
cannam@0: 
cannam@0: #include "PhaseVocoder.h"
cannam@0: #include "dsp/transforms/FFT.h"
cannam@0: #include <math.h>
cannam@0: 
cannam@0: //////////////////////////////////////////////////////////////////////
cannam@0: // Construction/Destruction
cannam@0: //////////////////////////////////////////////////////////////////////
cannam@0: 
cannam@64: PhaseVocoder::PhaseVocoder(unsigned int n) :
cannam@64:     m_n(n)
cannam@0: {
cannam@64:     m_fft = new FFTReal(m_n);
cannam@64:     m_realOut = new double[m_n];
cannam@64:     m_imagOut = new double[m_n];
cannam@0: }
cannam@0: 
cannam@0: PhaseVocoder::~PhaseVocoder()
cannam@0: {
cannam@64:     delete [] m_realOut;
cannam@64:     delete [] m_imagOut;
cannam@64:     delete m_fft;
cannam@0: }
cannam@0: 
cannam@0: void PhaseVocoder::FFTShift(unsigned int size, double *src)
cannam@0: {
cannam@55:     const int hs = size/2;
cannam@55:     for (int i = 0; i < hs; ++i) {
cannam@55:         double tmp = src[i];
cannam@55:         src[i] = src[i + hs];
cannam@55:         src[i + hs] = tmp;
cannam@0:     }
cannam@0: }
cannam@0: 
cannam@64: void PhaseVocoder::process(double *src, double *mag, double *theta)
cannam@0: {
cannam@64:     FFTShift( m_n, src);
cannam@64: 	
cannam@64:     m_fft->process(0, src, m_realOut, m_imagOut);
cannam@0: 
cannam@64:     getMagnitude( m_n/2, mag, m_realOut, m_imagOut);
cannam@64:     getPhase( m_n/2, theta, m_realOut, m_imagOut);
cannam@0: }
cannam@0: 
cannam@0: void PhaseVocoder::getMagnitude(unsigned int size, double *mag, double *real, double *imag)
cannam@0: {	
cannam@0:     unsigned int j;
cannam@0: 
cannam@0:     for( j = 0; j < size; j++)
cannam@0:     {
cannam@0: 	mag[ j ] = sqrt( real[ j ] * real[ j ] + imag[ j ] * imag[ j ]);
cannam@0:     }
cannam@0: }
cannam@0: 
cannam@0: void PhaseVocoder::getPhase(unsigned int size, double *theta, double *real, double *imag)
cannam@0: {
cannam@0:     unsigned int k;
cannam@0: 
cannam@0:     // Phase Angle "matlab" style 
cannam@0:     //Watch out for quadrant mapping  !!!
cannam@0:     for( k = 0; k < size; k++)
cannam@0:     {
cannam@0: 	theta[ k ] = atan2( -imag[ k ], real[ k ]);
cannam@0:     }	
cannam@0: }