160 lines
7.1 KiB
C++
160 lines
7.1 KiB
C++
/*
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ITU-T G.729A Speech Coder ANSI-C Source Code
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Version 1.1 Last modified: September 1996
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Copyright (c) 1996,
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AT&T, France Telecom, NTT, Universite de Sherbrooke
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All rights reserved.
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*/
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/*---------------------------------------------------------------------------*
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* Gain_predict() : make gcode0(exp_gcode0) *
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* Gain_update() : update table of past quantized energies. *
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* Gain_update_erasure() : update table of past quantized energies. *
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* (frame erasure) *
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* This function is used both Coder and Decoder. *
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*---------------------------------------------------------------------------*/
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#include "g729_typedef.h"
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#include "g729_basic_op.h"
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#include "g729_ld8a.h"
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#include "g729_tab_ld8a.h"
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#include "g729_oper_32b.h"
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/*---------------------------------------------------------------------------*
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* Function Gain_predict *
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* ~~~~~~~~~~~~~~~~~~~~~~ *
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* MA prediction is performed on the innovation energy (in dB with mean *
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* removed). *
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*---------------------------------------------------------------------------*/
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void
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Gain_predict (Word16 past_qua_en[], /* (i) Q10 :Past quantized energies */
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Word16 code[], /* (i) Q13 :Innovative vector. */
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Word16 L_subfr, /* (i) :Subframe length. */
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Word16 * gcode0, /* (o) Qxx :Predicted codebook gain */
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Word16 * exp_gcode0 /* (o) :Q-Format(gcode0) */
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)
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{
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Word16 i, exp, frac;
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Word32 L_tmp;
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/*-------------------------------*
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* Energy coming from code *
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*-------------------------------*/
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L_tmp = 0;
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for (i = 0; i < L_subfr; i++)
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L_tmp = L_mac (L_tmp, code[i], code[i]);
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/*-----------------------------------------------------------------*
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* Compute: means_ener - 10log10(ener_code/ L_sufr) *
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* Note: mean_ener change from 36 dB to 30 dB because input/2 *
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* *
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* = 30.0 - 10 log10( ener_code / lcode) + 10log10(2^27) *
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* !!ener_code in Q27!! *
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* = 30.0 - 3.0103 * log2(ener_code) + 10log10(40) + 10log10(2^27) *
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* = 30.0 - 3.0103 * log2(ener_code) + 16.02 + 81.278 *
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* = 127.298 - 3.0103 * log2(ener_code) *
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*-----------------------------------------------------------------*/
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Log2 (L_tmp, &exp, &frac); /* Q27->Q0 ^Q0 ^Q15 */
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L_tmp = Mpy_32_16 (exp, frac, -24660); /* Q0 Q15 Q13 -> ^Q14 */
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/* hi:Q0+Q13+1 */
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/* lo:Q15+Q13-15+1 */
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/* -24660[Q13]=-3.0103 */
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L_tmp = L_mac (L_tmp, 32588, 32); /* 32588*32[Q14]=127.298 */
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/*-----------------------------------------------------------------*
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* Compute gcode0. *
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* = Sum(i=0,3) g729_pred[i]*past_qua_en[i] - ener_code + mean_ener *
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*-----------------------------------------------------------------*/
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L_tmp = L_shl (L_tmp, 10); /* From Q14 to Q24 */
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for (i = 0; i < 4; i++)
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L_tmp = L_mac (L_tmp, g729_pred[i], past_qua_en[i]); /* Q13*Q10 ->Q24 */
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*gcode0 = extract_h (L_tmp); /* From Q24 to Q8 */
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/*-----------------------------------------------------------------*
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* gcode0 = pow(10.0, gcode0/20) *
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* = pow(2, 3.3219*gcode0/20) *
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* = pow(2, 0.166*gcode0) *
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*-----------------------------------------------------------------*/
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L_tmp = L_mult (*gcode0, 5439); /* *0.166 in Q15, result in Q24 */
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L_tmp = L_shr (L_tmp, 8); /* From Q24 to Q16 */
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L_Extract (L_tmp, &exp, &frac); /* Extract exponent of gcode0 */
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*gcode0 = extract_l (Pow2 (14, frac)); /* Put 14 as exponent so that */
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/* output of Pow2() will be: */
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/* 16768 < Pow2() <= 32767 */
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*exp_gcode0 = sub (14, exp);
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}
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/*---------------------------------------------------------------------------*
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* Function Gain_update *
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* ~~~~~~~~~~~~~~~~~~~~~~ *
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* update table of past quantized energies *
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*---------------------------------------------------------------------------*/
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void
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Gain_update (Word16 past_qua_en[], /* (io) Q10 :Past quantized energies */
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Word32 L_gbk12 /* (i) Q13 : gbk1[indice1][1]+gbk2[indice2][1] */
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)
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{
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Word16 i, tmp;
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Word16 exp, frac;
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Word32 L_acc;
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for (i = 3; i > 0; i--) {
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past_qua_en[i] = past_qua_en[i - 1]; /* Q10 */
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}
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/*----------------------------------------------------------------------*
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* -- past_qua_en[0] = 20*log10(gbk1[index1][1]+gbk2[index2][1]); -- *
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* 2 * 10 log10( gbk1[index1][1]+gbk2[index2][1] ) *
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* = 2 * 3.0103 log2( gbk1[index1][1]+gbk2[index2][1] ) *
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* = 2 * 3.0103 log2( gbk1[index1][1]+gbk2[index2][1] ) *
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* 24660:Q12(6.0205) *
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*----------------------------------------------------------------------*/
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Log2 (L_gbk12, &exp, &frac); /* L_gbk12:Q13 */
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L_acc = L_Comp (sub (exp, 13), frac); /* L_acc:Q16 */
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tmp = extract_h (L_shl (L_acc, 13)); /* tmp:Q13 */
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past_qua_en[0] = mult (tmp, 24660); /* past_qua_en[]:Q10 */
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}
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/*---------------------------------------------------------------------------*
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* Function Gain_update_erasure *
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
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* update table of past quantized energies (frame erasure) *
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*---------------------------------------------------------------------------*
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* av_pred_en = 0.0; *
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* for (i = 0; i < 4; i++) *
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* av_pred_en += past_qua_en[i]; *
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* av_pred_en = av_pred_en*0.25 - 4.0; *
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* if (av_pred_en < -14.0) av_pred_en = -14.0; *
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*---------------------------------------------------------------------------*/
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void
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Gain_update_erasure (Word16 past_qua_en[] /* (i) Q10 :Past quantized energies */
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)
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{
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Word16 i, av_pred_en;
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Word32 L_tmp;
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L_tmp = 0; /* Q10 */
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for (i = 0; i < 4; i++)
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L_tmp = L_add (L_tmp, L_deposit_l (past_qua_en[i]));
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av_pred_en = extract_l (L_shr (L_tmp, 2));
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av_pred_en = sub (av_pred_en, 4096); /* Q10 */
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if (sub (av_pred_en, -14336) < 0) {
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av_pred_en = -14336; /* 14336:14[Q10] */
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}
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for (i = 3; i > 0; i--) {
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past_qua_en[i] = past_qua_en[i - 1];
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}
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past_qua_en[0] = av_pred_en;
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}
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