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.
cannam@0:     This file copyright 2005-2006 Christian Landone.
cannam@0:     All rights reserved.
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@0: PhaseVocoder::PhaseVocoder()
cannam@0: {
cannam@0: 
cannam@0: }
cannam@0: 
cannam@0: PhaseVocoder::~PhaseVocoder()
cannam@0: {
cannam@0: 
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@0: void PhaseVocoder::process(unsigned int size, double *src, double *mag, double *theta)
cannam@0: {
cannam@0: 
cannam@0:     // Primary Interface to Phase Vocoder
cannam@0:     realOut = new double[ size ];
cannam@0:     imagOut = new double[ size ];
cannam@0: 
cannam@0:     FFTShift( size, src);
cannam@0: 	
cannam@0:     coreFFT( size, src, 0, realOut, imagOut);
cannam@0: 
cannam@0:     getMagnitude( size/2, mag, realOut, imagOut);
cannam@0:     getPhase( size/2, theta, realOut, imagOut);
cannam@0: 
cannam@0:     delete [] realOut;
cannam@0:     delete [] imagOut;
cannam@0: }
cannam@0: 
cannam@0: 
cannam@0: void PhaseVocoder::coreFFT( unsigned int NumSamples, double *RealIn, double* ImagIn, double *RealOut, double *ImagOut)
cannam@0: {
cannam@0:     // This function is taken from a standard freeware implementation defined in FFT.h
cannam@0:     // TODO: Use  FFTW
cannam@0:     FFT::process( NumSamples,0, RealIn, ImagIn, RealOut, 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: }