228 lines
6.7 KiB
C
228 lines
6.7 KiB
C
/* Copyright (C) 2006 Jean-Marc Valin */
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/**
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@file filterbank.c
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@brief Converting between psd and filterbank
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*/
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. The name of the author may not be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "filterbank.h"
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#include "arch.h"
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#include <math.h>
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#include "math_approx.h"
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#include "os_support.h"
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#ifdef FIXED_POINT
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#define toBARK(n) (MULT16_16(26829,spx_atan(SHR32(MULT16_16(97,n),2))) + MULT16_16(4588,spx_atan(MULT16_32_Q15(20,MULT16_16(n,n)))) + MULT16_16(3355,n))
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#else
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#define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n))
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#endif
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#define toMEL(n) (2595.f*log10(1.f+(n)/700.f))
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FilterBank *filterbank_new(int banks, spx_word32_t sampling, int len, int type)
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{
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FilterBank *bank;
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spx_word32_t df;
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spx_word32_t max_mel, mel_interval;
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int i;
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int id1;
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int id2;
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df = DIV32(SHL32(sampling,15),MULT16_16(2,len));
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max_mel = toBARK(EXTRACT16(sampling/2));
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mel_interval = PDIV32(max_mel,banks-1);
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bank = (FilterBank*)speex_alloc(sizeof(FilterBank));
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bank->nb_banks = banks;
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bank->len = len;
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bank->bank_left = (int*)speex_alloc(len*sizeof(int));
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bank->bank_right = (int*)speex_alloc(len*sizeof(int));
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bank->filter_left = (spx_word16_t*)speex_alloc(len*sizeof(spx_word16_t));
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bank->filter_right = (spx_word16_t*)speex_alloc(len*sizeof(spx_word16_t));
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/* Think I can safely disable normalisation that for fixed-point (and probably float as well) */
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#ifndef FIXED_POINT
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bank->scaling = (float*)speex_alloc(banks*sizeof(float));
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#endif
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for (i=0;i<len;i++)
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{
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spx_word16_t curr_freq;
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spx_word32_t mel;
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spx_word16_t val;
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curr_freq = EXTRACT16(MULT16_32_P15(i,df));
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mel = toBARK(curr_freq);
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if (mel > max_mel)
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break;
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#ifdef FIXED_POINT
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id1 = DIV32(mel,mel_interval);
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#else
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id1 = (int)(floor(mel/mel_interval));
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#endif
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if (id1>banks-2)
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{
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id1 = banks-2;
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val = Q15_ONE;
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} else {
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val = DIV32_16(mel - id1*mel_interval,EXTRACT16(PSHR32(mel_interval,15)));
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}
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id2 = id1+1;
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bank->bank_left[i] = id1;
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bank->filter_left[i] = SUB16(Q15_ONE,val);
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bank->bank_right[i] = id2;
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bank->filter_right[i] = val;
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}
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/* Think I can safely disable normalisation for fixed-point (and probably float as well) */
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#ifndef FIXED_POINT
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for (i=0;i<bank->nb_banks;i++)
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bank->scaling[i] = 0;
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for (i=0;i<bank->len;i++)
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{
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int id = bank->bank_left[i];
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bank->scaling[id] += bank->filter_left[i];
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id = bank->bank_right[i];
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bank->scaling[id] += bank->filter_right[i];
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}
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for (i=0;i<bank->nb_banks;i++)
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bank->scaling[i] = Q15_ONE/(bank->scaling[i]);
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#endif
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return bank;
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}
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void filterbank_destroy(FilterBank *bank)
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{
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speex_free(bank->bank_left);
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speex_free(bank->bank_right);
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speex_free(bank->filter_left);
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speex_free(bank->filter_right);
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#ifndef FIXED_POINT
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speex_free(bank->scaling);
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#endif
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speex_free(bank);
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}
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void filterbank_compute_bank32(FilterBank *bank, spx_word32_t *ps, spx_word32_t *mel)
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{
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int i;
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for (i=0;i<bank->nb_banks;i++)
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mel[i] = 0;
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for (i=0;i<bank->len;i++)
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{
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int id;
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id = bank->bank_left[i];
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mel[id] += MULT16_32_P15(bank->filter_left[i],ps[i]);
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id = bank->bank_right[i];
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mel[id] += MULT16_32_P15(bank->filter_right[i],ps[i]);
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}
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/* Think I can safely disable normalisation that for fixed-point (and probably float as well) */
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#ifndef FIXED_POINT
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/*for (i=0;i<bank->nb_banks;i++)
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mel[i] = MULT16_32_P15(Q15(bank->scaling[i]),mel[i]);
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*/
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#endif
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}
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void filterbank_compute_psd16(FilterBank *bank, spx_word16_t *mel, spx_word16_t *ps)
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{
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int i;
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for (i=0;i<bank->len;i++)
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{
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spx_word32_t tmp;
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int id1, id2;
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id1 = bank->bank_left[i];
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id2 = bank->bank_right[i];
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tmp = MULT16_16(mel[id1],bank->filter_left[i]);
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tmp += MULT16_16(mel[id2],bank->filter_right[i]);
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ps[i] = EXTRACT16(PSHR32(tmp,15));
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}
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}
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#ifndef FIXED_POINT
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void filterbank_compute_bank(FilterBank *bank, float *ps, float *mel)
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{
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int i;
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for (i=0;i<bank->nb_banks;i++)
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mel[i] = 0;
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for (i=0;i<bank->len;i++)
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{
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int id = bank->bank_left[i];
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mel[id] += bank->filter_left[i]*ps[i];
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id = bank->bank_right[i];
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mel[id] += bank->filter_right[i]*ps[i];
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}
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for (i=0;i<bank->nb_banks;i++)
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mel[i] *= bank->scaling[i];
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}
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void filterbank_compute_psd(FilterBank *bank, float *mel, float *ps)
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{
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int i;
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for (i=0;i<bank->len;i++)
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{
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int id = bank->bank_left[i];
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ps[i] = mel[id]*bank->filter_left[i];
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id = bank->bank_right[i];
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ps[i] += mel[id]*bank->filter_right[i];
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}
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}
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void filterbank_psy_smooth(FilterBank *bank, float *ps, float *mask)
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{
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/* Low freq slope: 14 dB/Bark*/
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/* High freq slope: 9 dB/Bark*/
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/* Noise vs tone: 5 dB difference */
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/* FIXME: Temporary kludge */
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float bark[100];
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int i;
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/* Assumes 1/3 Bark resolution */
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float decay_low = 0.34145f;
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float decay_high = 0.50119f;
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filterbank_compute_bank(bank, ps, bark);
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for (i=1;i<bank->nb_banks;i++)
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{
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/*float decay_high = 13-1.6*log10(bark[i-1]);
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decay_high = pow(10,(-decay_high/30.f));*/
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bark[i] = bark[i] + decay_high*bark[i-1];
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}
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for (i=bank->nb_banks-2;i>=0;i--)
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{
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bark[i] = bark[i] + decay_low*bark[i+1];
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}
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filterbank_compute_psd(bank, bark, mask);
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}
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#endif
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