ref: 974dddc7e5fc66721c791c6dac2582395f1f39ea
dir: /src/spectral/filterbank.c/
/* Copyright (C) 2007 Amaury Hazan <ahazan@iua.upf.edu> and Paul Brossier <piem@piem.org> 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 "spectral/filterbank.h" #include "mathutils.h" #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; } /* 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_mfcc(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("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++){ fft_freqs->data[0][bin_cnt]= aubio_bintofreq(bin_cnt, samplerate, 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]); //zeroing begining of filter for(bin_cnt=0; bin_cnt<win_s-1; bin_cnt++){ fb->filters[filter_cnt]->data[0][bin_cnt]=0.f; 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++; //positive slope for(; bin_cnt<win_s-1; bin_cnt++){ 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 for(; bin_cnt<win_s-1; bin_cnt++){ //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++; //zeroing tail for(; bin_cnt<win_s; bin_cnt++) 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 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; } fvec_t * aubio_filterbank_getchannel(aubio_filterbank_t * f, uint_t channel) { if ( (channel < f->n_filters) ) { return f->filters[channel]; } else { return NULL; } }