source: src/spectral/phasevoc.c @ e6c11e3

/*
   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 "fvec.h"
#include "cvec.h"
#include "mathutils.h"
#include "spectral/fft.h"
#include "spectral/phasevoc.h"

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


/** 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;
  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 */
  fvec_weight(pv->data, pv->w);
  /* shift */
  vec_shift(pv->data);
  /* calculate fft */
  aubio_fft_do (pv->fft,pv->data,fftgrain);
}

void aubio_pvoc_rdo(aubio_pvoc_t *pv,cvec_t * fftgrain, fvec_t * synthnew) {
  uint_t i;
  /* calculate rfft */
  aubio_fft_rdo(pv->fft,fftgrain,pv->synth);
  /* unshift */
  vec_shift(pv->synth);
  for (i=0; i<pv->channels; i++) {
    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_WRN("Hop size bigger than half the window size!\n");
  } */

  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_fft(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        = new_aubio_window (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_fvec(pv->w);
  del_aubio_fft(pv->fft);
  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;
}