source: src/phasevoc.c @ e638bcf

/*
   Copyright (C) 2003 Paul Brossier

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include "aubio_priv.h"
#include "sample.h"
#include "fft.h"
#include "mathutils.h"
#include "phasevoc.h"

/** phasevocoder internal object */
struct _aubio_pvoc_t {
        /** grain length */
        uint_t win_s;
        /** overlap step */
        uint_t hop_s;
        /** number of channels */
        uint_t channels;
        /** spectral data */
        aubio_mfft_t * fft;
        /**cur output grain             [win_s] */
        fvec_t * synth;          
        /**last input frame             [win_s-hop_s] */
        fvec_t * synthold; 
        /**current input grain          [win_s] */
        fvec_t * data;           
        /**last input frame             [win_s-hop_s] */
        fvec_t * dataold;  
        /** grain window                [win_s] */
        float * w;
};


/** returns data and dataold slided by hop_s */
static void aubio_pvoc_swapbuffers(
                smpl_t * data,
                smpl_t * dataold,
                const smpl_t * datanew,
                uint_t win_s, uint_t hop_s);
/** do additive synthesis from 'old' and 'cur' */
static void aubio_pvoc_addsynth(
                const smpl_t * synth,
                smpl_t * synthold,
                smpl_t * synthnew, 
                uint_t win_s, uint_t hop_s);


void aubio_pvoc_do(aubio_pvoc_t *pv, fvec_t * datanew, cvec_t *fftgrain) {
        uint_t i,j;
        for (i=0; i<pv->channels; i++) {
                /* slide  */
                aubio_pvoc_swapbuffers(pv->data->data[i],pv->dataold->data[i],
                                datanew->data[i],pv->win_s,pv->hop_s);
                /* windowing */
                for (j=0; j<pv->win_s; j++) pv->data->data[i][j] *= pv->w[j];
        }
        /* shift */
        vec_shift(pv->data);
        /* calculate fft */
        aubio_mfft_do (pv->fft,pv->data,fftgrain);
}

void aubio_pvoc_rdo(aubio_pvoc_t *pv,cvec_t * fftgrain, fvec_t * synthnew) {
        uint_t i,j;
        /* calculate rfft */
        aubio_mfft_rdo(pv->fft,fftgrain,pv->synth);
        /* unshift */
        vec_shift(pv->synth);
        for (i=0; i<pv->channels; i++) {
                for (j=0; j<pv->win_s; j++) pv->synth->data[i][j] *= pv->w[j];
                aubio_pvoc_addsynth(pv->synth->data[i],pv->synthold->data[i],
                                synthnew->data[i],pv->win_s,pv->hop_s);
        }
}

aubio_pvoc_t * new_aubio_pvoc (uint_t win_s, uint_t hop_s, uint_t channels) {
        aubio_pvoc_t * pv = AUBIO_NEW(aubio_pvoc_t);

        if (win_s < 2*hop_s) {
                AUBIO_ERR("Hop size bigger than half the window size!\n");
                AUBIO_ERR("Resetting hop size to half the window size.\n");
                hop_s = win_s / 2;
        }

        if (hop_s < 1) {
                AUBIO_ERR("Hop size is smaller than 1!\n");
                AUBIO_ERR("Resetting hop size to half the window size.\n");
                hop_s = win_s / 2;
        }
        
        pv->fft      = new_aubio_mfft(win_s,channels);

        /* remember old */
        pv->data     = new_fvec (win_s, channels);
        pv->synth    = new_fvec (win_s, channels);

        /* new input output */
        pv->dataold  = new_fvec  (win_s-hop_s, channels);
        pv->synthold = new_fvec (win_s-hop_s, channels);
        pv->w        = AUBIO_ARRAY(smpl_t,win_s);
        aubio_window(pv->w,win_s,aubio_win_hanningz);

        pv->channels = channels;
        pv->hop_s    = hop_s;
        pv->win_s    = win_s;

        return pv;
}

void del_aubio_pvoc(aubio_pvoc_t *pv) {
        del_fvec(pv->data);
        del_fvec(pv->synth);
        del_fvec(pv->dataold);
        del_fvec(pv->synthold);
        del_aubio_mfft(pv->fft);
        AUBIO_FREE(pv->w);
        AUBIO_FREE(pv);
}

static void aubio_pvoc_swapbuffers(smpl_t * data, smpl_t * dataold, 
                const smpl_t * datanew, uint_t win_s, uint_t hop_s)
{
        uint_t i;
        for (i=0;i<win_s-hop_s;i++)
                data[i] = dataold[i];
        for (i=0;i<hop_s;i++)
                data[win_s-hop_s+i] = datanew[i];
        for (i=0;i<win_s-hop_s;i++)
                dataold[i] = data[i+hop_s];
}

static void aubio_pvoc_addsynth(const smpl_t * synth, smpl_t * synthold, 
                smpl_t * synthnew, uint_t win_s, uint_t hop_s)
{
        uint_t i;
        smpl_t scale = 2*hop_s/(win_s+.0);
        /* add new synth to old one and put result in synthnew */
        for (i=0;i<hop_s;i++)                                           
                synthnew[i] = synthold[i]+synth[i]*scale;
        /* shift synthold */
        for (i=0;i<win_s-2*hop_s;i++)   
                synthold[i] = synthold[i+hop_s];
        /* erase last frame in synthold */
        for (i=win_s-hop_s;i<win_s;i++) 
                synthold[i-hop_s]=0.;
        /* additive synth */
        for (i=0;i<win_s-hop_s;i++)     
                synthold[i] += synth[i+hop_s]*scale;
}