ref: bc4ba753e5c7e50f6149add3c46e47f54ba23f05
dir: /src/filterbank.c/
/*
Copyright (C) 2007 Amaury Hazan <[email protected]>
and Paul Brossier <[email protected]>
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 "filterbank.h"
#include "stdio.h"
#define USE_EQUAL_GAIN 1
#define VERY_SMALL_NUMBER 2e-42
/** \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;
fvec_t **filters;
};
aubio_filterbank_t * new_aubio_filterbank(uint_t n_filters, uint_t win_s){
/** allocating space for filterbank object */
aubio_filterbank_t * fb = AUBIO_NEW(aubio_filterbank_t);
uint_t filter_cnt;
fb->win_s=win_s;
fb->n_filters=n_filters;
/** allocating filter tables */
fb->filters=AUBIO_ARRAY(fvec_t*,n_filters);
for (filter_cnt=0; filter_cnt<n_filters; filter_cnt++)
/* considering one-channel filters */
fb->filters[filter_cnt]=new_fvec(win_s, 1);
return fb;
}
aubio_filterbank_t * new_aubio_filterbank_mfcc(uint_t n_filters, uint_t win_s, uint_t samplerate, smpl_t freq_min, smpl_t freq_max){
smpl_t nyquist = samplerate/2.;
uint_t style = 1;
aubio_filterbank_t * fb = new_aubio_filterbank(n_filters, win_s);
uint_t n, i, k, *fft_peak, M, next_peak;
smpl_t norm, mel_freq_max, mel_freq_min, norm_fact, height, inc, val,
freq_bw_mel, *mel_peak, *height_norm, *lin_peak;
mel_peak = height_norm = lin_peak = NULL;
fft_peak = NULL;
norm = 1;
mel_freq_max = 1127 * log(1 + freq_max / 700);
mel_freq_min = 1127 * log(1 + freq_min / 700);
freq_bw_mel = (mel_freq_max - mel_freq_min) / fb->n_filters;
mel_peak = (smpl_t *)malloc((fb->n_filters + 2) * sizeof(smpl_t));
/* +2 for zeros at start and end */
lin_peak = (smpl_t *)malloc((fb->n_filters + 2) * sizeof(smpl_t));
fft_peak = (uint_t *)malloc((fb->n_filters + 2) * sizeof(uint_t));
height_norm = (smpl_t *)malloc(fb->n_filters * sizeof(smpl_t));
if(mel_peak == NULL || height_norm == NULL ||
lin_peak == NULL || fft_peak == NULL)
return NULL;
M = fb->win_s >> 1;
mel_peak[0] = mel_freq_min;
lin_peak[0] = 700 * (exp(mel_peak[0] / 1127) - 1);
fft_peak[0] = lin_peak[0] / nyquist * M;
for (n = 1; n <= fb->n_filters; n++){
/*roll out peak locations - mel, linear and linear on fft window scale */
mel_peak[n] = mel_peak[n - 1] + freq_bw_mel;
lin_peak[n] = 700 * (exp(mel_peak[n] / 1127) -1);
fft_peak[n] = lin_peak[n] / nyquist * M;
}
for (n = 0; n < fb->n_filters; n++){
/*roll out normalised gain of each peak*/
if (style == USE_EQUAL_GAIN){
height = 1;
norm_fact = norm;
}
else{
height = 2 / (lin_peak[n + 2] - lin_peak[n]);
norm_fact = norm / (2 / (lin_peak[2] - lin_peak[0]));
}
height_norm[n] = height * norm_fact;
}
i = 0;
for(n = 0; n < fb->n_filters; n++){
/*calculate the rise increment*/
if(n > 0)
inc = height_norm[n] / (fft_peak[n] - fft_peak[n - 1]);
else
inc = height_norm[n] / fft_peak[n];
val = 0;
/*zero the start of the array*/
for(k = 0; k < i; k++)
fb->filters[n]->data[0][k]=0.f;
/*fill in the rise */
for(; i <= fft_peak[n]; i++){
fb->filters[n]->data[0][k]=val;
val += inc;
}
/*calculate the fall increment */
inc = height_norm[n] / (fft_peak[n + 1] - fft_peak[n]);
val = 0;
next_peak = fft_peak[n + 1];
/*reverse fill the 'fall' */
for(i = next_peak; i > fft_peak[n]; i--){
fb->filters[n]->data[0][k]=val;
val += inc;
}
/*zero the rest of the array*/
for(k = next_peak + 1; k < fb->win_s; k++)
fb->filters[n]->data[0][k]=0.f;
}
free(mel_peak);
free(lin_peak);
free(height_norm);
free(fft_peak);
return fb;
}
/*
FB initialization based on Slaney's auditory toolbox
TODO:
*solve memory leak problems while
*solve quantization issues when constructing signal:
*bug for win_s=512
*corrections for win_s=1024 -> why even filters with smaller amplitude
*/
aubio_filterbank_t * new_aubio_filterbank_mfcc2(uint_t n_filters, uint_t win_s, uint_t samplerate, smpl_t freq_min, smpl_t freq_max){
aubio_filterbank_t * fb = new_aubio_filterbank(n_filters, win_s);
//slaney params
smpl_t lowestFrequency = 133.3333;
smpl_t linearSpacing = 66.66666666;
smpl_t logSpacing = 1.0711703;
uint_t linearFilters = 13;
uint_t logFilters = 27;
uint_t allFilters = linearFilters + logFilters;
//buffers for computing filter frequencies
fvec_t * freqs=new_fvec(allFilters+2 , 1);
fvec_t * lower_freqs=new_fvec( allFilters, 1);
fvec_t * upper_freqs=new_fvec( allFilters, 1);
fvec_t * center_freqs=new_fvec( allFilters, 1);
fvec_t * triangle_heights=new_fvec( allFilters, 1);
//lookup table of each bin frequency in hz
fvec_t * fft_freqs=new_fvec(win_s, 1);
uint_t filter_cnt, bin_cnt;
//first step: filling all the linear filter frequencies
for(filter_cnt=0; filter_cnt<linearFilters; filter_cnt++){
freqs->data[0][filter_cnt]=lowestFrequency+ filter_cnt*linearSpacing;
}
smpl_t lastlinearCF=freqs->data[0][filter_cnt-1];
//second step: filling all the log filter frequencies
for(filter_cnt=0; filter_cnt<logFilters+2; filter_cnt++){
freqs->data[0][filter_cnt+linearFilters]=lastlinearCF*(pow(logSpacing,filter_cnt+1));
}
//Option 1. copying interesting values to lower_freqs, center_freqs and upper freqs arrays
//TODO: would be nicer to have a reference to freqs->data, anyway we do not care in this init step
for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
lower_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt];
center_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt+1];
upper_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt+2];
}
//computing triangle heights so that each triangle has unit area
for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
triangle_heights->data[0][filter_cnt]=2./(upper_freqs->data[0][filter_cnt]-lower_freqs->data[0][filter_cnt]);
}
//AUBIO_DBG
AUBIO_DBG("filter tables frequencies\n");
for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++)
AUBIO_DBG("filter n. %d %f %f %f %f\n",filter_cnt, lower_freqs->data[0][filter_cnt], center_freqs->data[0][filter_cnt], upper_freqs->data[0][filter_cnt], triangle_heights->data[0][filter_cnt]);
//filling the fft_freqs lookup table, which assigns the frequency in hz to each bin
for(bin_cnt=0; bin_cnt<win_s; bin_cnt++){
//TODO: check the formula!
fft_freqs->data[0][bin_cnt]= (smpl_t)samplerate* (smpl_t)bin_cnt/ (smpl_t)win_s;
}
//building each filter table
for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
//TODO:check special case : lower freq =0
//calculating rise increment in mag/Hz
smpl_t riseInc= triangle_heights->data[0][filter_cnt]/(center_freqs->data[0][filter_cnt]-lower_freqs->data[0][filter_cnt]);
AUBIO_DBG("\nfilter %d",filter_cnt);
//zeroing begining of filter
AUBIO_DBG("\nzero begin\n");
for(bin_cnt=0; bin_cnt<win_s-1; bin_cnt++){
//zeroing beigining of array
fb->filters[filter_cnt]->data[0][bin_cnt]=0.f;
AUBIO_DBG(".");
//AUBIO_DBG("%f %f %f\n", fft_freqs->data[0][bin_cnt], fft_freqs->data[0][bin_cnt+1], lower_freqs->data[0][filter_cnt]);
if(fft_freqs->data[0][bin_cnt]<= lower_freqs->data[0][filter_cnt] && fft_freqs->data[0][bin_cnt+1]> lower_freqs->data[0][filter_cnt]){
break;
}
}
bin_cnt++;
AUBIO_DBG("\npos slope\n");
//positive slope
for(; bin_cnt<win_s-1; bin_cnt++){
AUBIO_DBG(".");
fb->filters[filter_cnt]->data[0][bin_cnt]=(fft_freqs->data[0][bin_cnt]-lower_freqs->data[0][filter_cnt])*riseInc;
//if(fft_freqs->data[0][bin_cnt]<= center_freqs->data[0][filter_cnt] && fft_freqs->data[0][bin_cnt+1]> center_freqs->data[0][filter_cnt])
if(fft_freqs->data[0][bin_cnt+1]> center_freqs->data[0][filter_cnt])
break;
}
//bin_cnt++;
//negative slope
AUBIO_DBG("\nneg slope\n");
for(; bin_cnt<win_s-1; bin_cnt++){
//AUBIO_DBG(".");
//checking whether last value is less than 0...
smpl_t val=triangle_heights->data[0][filter_cnt]-(fft_freqs->data[0][bin_cnt]-center_freqs->data[0][filter_cnt])*riseInc;
if(val>=0)
fb->filters[filter_cnt]->data[0][bin_cnt]=val;
else fb->filters[filter_cnt]->data[0][bin_cnt]=0.f;
//if(fft_freqs->data[0][bin_cnt]<= upper_freqs->data[0][bin_cnt] && fft_freqs->data[0][bin_cnt+1]> upper_freqs->data[0][filter_cnt])
//TODO: CHECK whether bugfix correct
if(fft_freqs->data[0][bin_cnt+1]> upper_freqs->data[0][filter_cnt])
break;
}
//bin_cnt++;
AUBIO_DBG("\nzero end\n");
//zeroing tail
for(; bin_cnt<win_s; bin_cnt++)
//AUBIO_DBG(".");
fb->filters[filter_cnt]->data[0][bin_cnt]=0.f;
}
del_fvec(freqs);
del_fvec(lower_freqs);
del_fvec(upper_freqs);
del_fvec(center_freqs);
del_fvec(triangle_heights);
del_fvec(fft_freqs);
return fb;
}
void aubio_dump_filterbank(aubio_filterbank_t * fb){
FILE * mlog;
mlog=fopen("filterbank.txt","w");
int k,n;
//dumping filter values
//smpl_t area_tmp=0.f;
for(n = 0; n < fb->n_filters; n++){
for(k = 0; k < fb->win_s; k++){
fprintf(mlog,"%f ",fb->filters[n]->data[0][k]);
}
fprintf(mlog,"\n");
}
if(mlog) fclose(mlog);
}
void del_aubio_filterbank(aubio_filterbank_t * fb){
uint_t filter_cnt;
/** deleting filter tables first */
for (filter_cnt=0; filter_cnt<fb->n_filters; filter_cnt++)
del_fvec(fb->filters[filter_cnt]);
AUBIO_FREE(fb->filters);
AUBIO_FREE(fb);
}
void aubio_filterbank_do(aubio_filterbank_t * f, cvec_t * in, fvec_t *out) {
uint_t n, filter_cnt;
for(filter_cnt = 0; (filter_cnt < f->n_filters)
&& (filter_cnt < out->length); filter_cnt++){
out->data[0][filter_cnt] = 0.f;
for(n = 0; n < in->length; n++){
out->data[0][filter_cnt] += in->norm[0][n]
* f->filters[filter_cnt]->data[0][n];
}
out->data[0][filter_cnt] =
LOG(out->data[0][filter_cnt] < VERY_SMALL_NUMBER ?
VERY_SMALL_NUMBER : out->data[0][filter_cnt]);
}
return;
}