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268 lines
8.4 KiB
268 lines
8.4 KiB
/* 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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#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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float vbr_nb_thresh[9][11]={ |
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{-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0}, /* CNG */ |
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{ 3.5, 2.5, 2.0, 1.2, 0.5, 0.0, -0.5, -0.7, -0.8, -0.9, -1.0}, /* 2 kbps */ |
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{10.0, 6.5, 5.2, 4.5, 3.9, 3.5, 3.0, 2.5, 2.3, 1.8, 1.0}, /* 6 kbps */ |
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{11.0, 8.8, 7.5, 6.5, 5.0, 3.9, 3.9, 3.9, 3.5, 3.0, 1.0}, /* 8 kbps */ |
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{11.0, 11.0, 9.9, 9.0, 8.0, 7.0, 6.5, 6.0, 5.0, 4.0, 2.0}, /* 11 kbps */ |
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{11.0, 11.0, 11.0, 11.0, 9.5, 9.0, 8.0, 7.0, 6.5, 5.0, 3.0}, /* 15 kbps */ |
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{11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 9.5, 8.5, 8.0, 6.5, 4.0}, /* 18 kbps */ |
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{11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 9.8, 7.5, 5.5}, /* 24 kbps */ |
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{ 8.0, 5.0, 3.7, 3.0, 2.5, 2.0, 1.8, 1.5, 1.0, 0.0, 0.0} /* 4 kbps */ |
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}; |
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float vbr_hb_thresh[5][11]={ |
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{-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0}, /* silence */ |
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{-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0}, /* 2 kbps */ |
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{11.0, 11.0, 9.5, 8.5, 7.5, 6.0, 5.0, 3.9, 3.0, 2.0, 1.0}, /* 6 kbps */ |
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{11.0, 11.0, 11.0, 11.0, 11.0, 9.5, 8.7, 7.8, 7.0, 6.5, 4.0}, /* 10 kbps */ |
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{11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 11.0, 9.8, 7.5, 5.5} /* 18 kbps */ |
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}; |
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float vbr_uhb_thresh[2][11]={ |
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{-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0}, /* silence */ |
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{ 3.9, 2.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0} /* 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, float *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 += sig[i]*sig[i]; |
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for (i=len>>1;i<len;i++) |
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ener2 += 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(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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