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@225:     This file copyright 2005-2006 Christian Landone.
c@225:     All rights reserved.
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@225: PhaseVocoder::PhaseVocoder()
c@225: {
c@225: 
c@225: }
c@225: 
c@225: PhaseVocoder::~PhaseVocoder()
c@225: {
c@225: 
c@225: }
c@225: 
c@225: void PhaseVocoder::FFTShift(unsigned int size, double *src)
c@225: {
c@225:     // IN-place Rotation of FFT arrays
c@225:     unsigned int i;
c@225: 
c@225:     shiftBuffer = new double[size/2];
c@225: 
c@225:     for( i = 0; i < size/2; i++)
c@225:     {
c@225: 	shiftBuffer[ i ] = src[ i ];
c@225: 	src[ i ] = src[ i + size/2];
c@225:     }
c@225: 	
c@225:     for( i =size/2; i < size;  i++)
c@225:     {
c@225: 	src[ i ] = shiftBuffer[ i -(size/2)];
c@225:     }
c@225: 
c@225:     delete [] shiftBuffer;
c@225: 
c@225: }
c@225: 
c@225: void PhaseVocoder::process(unsigned int size, double *src, double *mag, double *theta)
c@225: {
c@225: 
c@225:     // Primary Interface to Phase Vocoder
c@225:     realOut = new double[ size ];
c@225:     imagOut = new double[ size ];
c@225: 
c@225:     FFTShift( size, src);
c@225: 	
c@225:     coreFFT( size, src, 0, realOut, imagOut);
c@225: 
c@225:     getMagnitude( size/2, mag, realOut, imagOut);
c@225:     getPhase( size/2, theta, realOut, imagOut);
c@225: 
c@225:     delete [] realOut;
c@225:     delete [] imagOut;
c@225: }
c@225: 
c@225: 
c@225: void PhaseVocoder::coreFFT( unsigned int NumSamples, double *RealIn, double* ImagIn, double *RealOut, double *ImagOut)
c@225: {
c@225:     // This function is taken from a standard freeware implementation defined in FFT.h
c@225:     // TODO: Use  FFTW
c@225:     FFT::process( NumSamples,0, RealIn, ImagIn, RealOut, 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: }