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276 lines
8.5 KiB
C
276 lines
8.5 KiB
C
12 years ago
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/* Copyright (C) 2002 Jean-Marc Valin
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File: vbr.c
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VBR-related routines
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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
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- 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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- Neither the name of the Xiph.org Foundation nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE 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 "vbr.h"
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#include <math.h>
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#define sqr(x) ((x)*(x))
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#define MIN_ENERGY 6000
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#define NOISE_POW .3
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#ifndef DISABLE_VBR
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const float vbr_nb_thresh[9][11]={
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{-1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f}, /* CNG */
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{ 4.0f, 2.5f, 2.0f, 1.2f, 0.5f, 0.0f, -0.5f, -0.7f, -0.8f, -0.9f, -1.0f}, /* 2 kbps */
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{10.0f, 6.5f, 5.2f, 4.5f, 3.9f, 3.5f, 3.0f, 2.5f, 2.3f, 1.8f, 1.0f}, /* 6 kbps */
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{11.0f, 8.8f, 7.5f, 6.5f, 5.0f, 3.9f, 3.9f, 3.9f, 3.5f, 3.0f, 1.0f}, /* 8 kbps */
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{11.0f, 11.0f, 9.9f, 8.5f, 7.0f, 6.0f, 4.5f, 4.0f, 4.0f, 4.0f, 2.0f}, /* 11 kbps */
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{11.0f, 11.0f, 11.0f, 11.0f, 9.5f, 8.5f, 8.0f, 7.0f, 6.0f, 5.0f, 3.0f}, /* 15 kbps */
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{11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 9.5f, 8.5f, 7.0f, 6.0f, 5.0f}, /* 18 kbps */
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{11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 9.8f, 9.5f, 7.5f}, /* 24 kbps */
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{ 7.0f, 4.5f, 3.7f, 3.0f, 2.5f, 2.0f, 1.8f, 1.5f, 1.0f, 0.0f, 0.0f} /* 4 kbps */
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};
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const float vbr_hb_thresh[5][11]={
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{-1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f}, /* silence */
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{-1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f}, /* 2 kbps */
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{11.0f, 11.0f, 9.5f, 8.5f, 7.5f, 6.0f, 5.0f, 3.9f, 3.0f, 2.0f, 1.0f}, /* 6 kbps */
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{11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 9.5f, 8.7f, 7.8f, 7.0f, 6.5f, 4.0f}, /* 10 kbps */
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{11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 11.0f, 9.8f, 7.5f, 5.5f} /* 18 kbps */
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};
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const float vbr_uhb_thresh[2][11]={
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{-1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f}, /* silence */
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{ 3.9f, 2.5f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f} /* 2 kbps */
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};
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void vbr_init(VBRState *vbr)
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{
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int i;
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vbr->average_energy=0;
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vbr->last_energy=1;
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vbr->accum_sum=0;
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vbr->energy_alpha=.1;
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vbr->soft_pitch=0;
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vbr->last_pitch_coef=0;
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vbr->last_quality=0;
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vbr->noise_accum = .05*pow(MIN_ENERGY, NOISE_POW);
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vbr->noise_accum_count=.05;
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vbr->noise_level=vbr->noise_accum/vbr->noise_accum_count;
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vbr->consec_noise=0;
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for (i=0;i<VBR_MEMORY_SIZE;i++)
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vbr->last_log_energy[i] = log(MIN_ENERGY);
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}
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/*
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This function should analyse the signal and decide how critical the
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coding error will be perceptually. The following factors should be
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taken into account:
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-Attacks (positive energy derivative) should be coded with more bits
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-Stationary voiced segments should receive more bits
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-Segments with (very) low absolute energy should receive less bits (maybe
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only shaped noise?)
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-DTX for near-zero energy?
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-Stationary fricative segments should have less bits
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-Temporal masking: when energy slope is decreasing, decrease the bit-rate
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-Decrease bit-rate for males (low pitch)?
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-(wideband only) less bits in the high-band when signal is very
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non-stationary (harder to notice high-frequency noise)???
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*/
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float vbr_analysis(VBRState *vbr, spx_word16_t *sig, int len, int pitch, float pitch_coef)
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{
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int i;
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float ener=0, ener1=0, ener2=0;
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float qual=7;
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int va;
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float log_energy;
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float non_st=0;
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float voicing;
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float pow_ener;
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for (i=0;i<len>>1;i++)
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ener1 += ((float)sig[i])*sig[i];
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for (i=len>>1;i<len;i++)
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ener2 += ((float)sig[i])*sig[i];
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ener=ener1+ener2;
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log_energy = log(ener+MIN_ENERGY);
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for (i=0;i<VBR_MEMORY_SIZE;i++)
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non_st += sqr(log_energy-vbr->last_log_energy[i]);
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non_st = non_st/(30*VBR_MEMORY_SIZE);
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if (non_st>1)
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non_st=1;
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voicing = 3*(pitch_coef-.4)*fabs(pitch_coef-.4);
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vbr->average_energy = (1-vbr->energy_alpha)*vbr->average_energy + vbr->energy_alpha*ener;
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vbr->noise_level=vbr->noise_accum/vbr->noise_accum_count;
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pow_ener = pow(ener,NOISE_POW);
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if (vbr->noise_accum_count<.06 && ener>MIN_ENERGY)
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vbr->noise_accum = .05*pow_ener;
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if ((voicing<.3 && non_st < .2 && pow_ener < 1.2*vbr->noise_level)
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|| (voicing<.3 && non_st < .05 && pow_ener < 1.5*vbr->noise_level)
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|| (voicing<.4 && non_st < .05 && pow_ener < 1.2*vbr->noise_level)
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|| (voicing<0 && non_st < .05))
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{
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float tmp;
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va = 0;
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vbr->consec_noise++;
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if (pow_ener > 3*vbr->noise_level)
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tmp = 3*vbr->noise_level;
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else
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tmp = pow_ener;
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if (vbr->consec_noise>=4)
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{
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vbr->noise_accum = .95*vbr->noise_accum + .05*tmp;
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vbr->noise_accum_count = .95*vbr->noise_accum_count + .05;
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}
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} else {
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va = 1;
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vbr->consec_noise=0;
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}
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if (pow_ener < vbr->noise_level && ener>MIN_ENERGY)
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{
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vbr->noise_accum = .95*vbr->noise_accum + .05*pow_ener;
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vbr->noise_accum_count = .95*vbr->noise_accum_count + .05;
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}
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/* Checking for very low absolute energy */
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if (ener < 30000)
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{
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qual -= .7;
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if (ener < 10000)
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qual-=.7;
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if (ener < 3000)
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qual-=.7;
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} else {
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float short_diff, long_diff;
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short_diff = log((ener+1)/(1+vbr->last_energy));
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long_diff = log((ener+1)/(1+vbr->average_energy));
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/*fprintf (stderr, "%f %f\n", short_diff, long_diff);*/
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if (long_diff<-5)
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long_diff=-5;
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if (long_diff>2)
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long_diff=2;
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if (long_diff>0)
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qual += .6*long_diff;
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if (long_diff<0)
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qual += .5*long_diff;
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if (short_diff>0)
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{
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if (short_diff>5)
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short_diff=5;
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qual += .5*short_diff;
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}
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/* Checking for energy increases */
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if (ener2 > 1.6*ener1)
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qual += .5;
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}
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vbr->last_energy = ener;
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vbr->soft_pitch = .6*vbr->soft_pitch + .4*pitch_coef;
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qual += 2.2*((pitch_coef-.4) + (vbr->soft_pitch-.4));
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if (qual < vbr->last_quality)
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qual = .5*qual + .5*vbr->last_quality;
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if (qual<4)
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qual=4;
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if (qual>10)
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qual=10;
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/*
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if (vbr->consec_noise>=2)
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qual-=1.3;
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if (vbr->consec_noise>=5)
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qual-=1.3;
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if (vbr->consec_noise>=12)
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qual-=1.3;
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*/
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if (vbr->consec_noise>=3)
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qual=4;
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if (vbr->consec_noise)
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qual -= 1.0 * (log(3.0 + vbr->consec_noise)-log(3));
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if (qual<0)
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qual=0;
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if (ener<60000)
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{
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if (vbr->consec_noise>2)
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qual-=0.5*(log(3.0 + vbr->consec_noise)-log(3));
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if (ener<10000&&vbr->consec_noise>2)
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qual-=0.5*(log(3.0 + vbr->consec_noise)-log(3));
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if (qual<0)
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qual=0;
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qual += .3*log(.0001+ener/60000.0);
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}
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if (qual<-1)
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qual=-1;
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/*printf ("%f %f %f %f %d\n", qual, voicing, non_st, pow_ener/(.01+vbr->noise_level), va);*/
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vbr->last_pitch_coef = pitch_coef;
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vbr->last_quality = qual;
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for (i=VBR_MEMORY_SIZE-1;i>0;i--)
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vbr->last_log_energy[i] = vbr->last_log_energy[i-1];
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vbr->last_log_energy[0] = log_energy;
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/*printf ("VBR: %f %f %f %d %f\n", (float)(log_energy-log(vbr->average_energy+MIN_ENERGY)), non_st, voicing, va, vbr->noise_level);*/
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return qual;
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}
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void vbr_destroy(VBRState *vbr)
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{
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}
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#endif /* #ifndef DISABLE_VBR */
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