source: src/spectral/filterbank.c @ 7aa4aaa

/*
  Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org>
                      and Amaury Hazan <ahazan@iua.upf.edu>

  This file is part of aubio.

  aubio 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 3 of the License, or
  (at your option) any later version.

  aubio 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 aubio.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "aubio_priv.h"
#include "fvec.h"
#include "fmat.h"
#include "cvec.h"
#include "spectral/filterbank.h"
#include "mathutils.h"

/** \brief A structure to store a set of n_filters filters of lenghts win_s */
struct _aubio_filterbank_t
{
  uint_t win_s;
  uint_t n_filters;
  fmat_t *filters;
};

aubio_filterbank_t *
new_aubio_filterbank (uint_t n_filters, uint_t win_s)
{
  /* allocate space for filterbank object */
  aubio_filterbank_t *fb = AUBIO_NEW (aubio_filterbank_t);
  fb->win_s = win_s;
  fb->n_filters = n_filters;

  /* allocate filter tables, a matrix of length win_s and of height n_filters */
  fb->filters = new_fmat (n_filters, win_s / 2 + 1);

  return fb;
}

void
del_aubio_filterbank (aubio_filterbank_t * fb)
{
  del_fmat (fb->filters);
  AUBIO_FREE (fb);
}

void
aubio_filterbank_do (aubio_filterbank_t * f, cvec_t * in, fvec_t * out)
{
  uint_t j, fn;

  /* apply filter to all input channel, provided out has enough channels */
  uint_t max_filters = MIN (f->n_filters, out->length);
  uint_t max_length = MIN (in->length, f->filters->length);

  /* reset all values in output vector */
  fvec_zeros (out);

  /* for each filter */
  for (fn = 0; fn < max_filters; fn++) {
    /* for each sample */
    for (j = 0; j < max_length; j++) {
      out->data[fn] += in->norm[j] * f->filters->data[fn][j];
    }
  }

  return;
}

fmat_t *
aubio_filterbank_get_coeffs (aubio_filterbank_t * f)
{
  return f->filters;
}

uint_t
aubio_filterbank_set_coeffs (aubio_filterbank_t * f, fmat_t * filter_coeffs)
{
  fmat_copy(filter_coeffs, f->filters);
  return 0;
}