FreeCalypso > hg > gsm-codec-lib
view libgsmefr/d_gains.c @ 95:f80a3202c8ff
libgsmefr: implement main decoder wrapper
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 26 Nov 2022 18:58:56 +0000 |
parents | a18782a7d270 |
children | 9b07190a6d08 |
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/************************************************************************* * * FILE NAME: D_GAINS.C * * FUNCTIONS DEFINED IN THIS FILE: * * d_gain_pitch(), d_gain_code() and gmed5() * * MA prediction is performed on the innovation energy * ( in dB/(20*log10(2)) ) with mean removed. *************************************************************************/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "oper_32b.h" #include "no_count.h" #include "sig_proc.h" #include "memops.h" #include "codec.h" #include "gains_tb.h" #include "cnst.h" #include "dec_state.h" #include "dtx.h" /************************************************************************* * * FUNCTION: gmed5 * * PURPOSE: calculates 5-point median. * * DESCRIPTION: * *************************************************************************/ static Word16 gmed5 ( /* out : index of the median value (0...4) */ Word16 ind[] /* in : Past gain values */ ) { Word16 i, j, ix = 0, tmp[5]; Word16 max, tmp2[5]; Copy (ind, tmp2, 5); for (i = 0; i < 5; i++) { max = -8192; move16 (); for (j = 0; j < 5; j++) { if (tmp2[j] >= max) { max = tmp2[j]; move16 (); ix = j; move16 (); } } tmp2[ix] = -16384; move16 (); tmp[i] = ix; move16 (); } return (ind[tmp[2]]); } /************************************************************************* * * FUNCTION: d_gain_pitch * * PURPOSE: decodes the pitch gain using the received index. * * DESCRIPTION: * In case of no frame erasure, the gain is obtained from the * quantization table at the given index; otherwise, a downscaled * past gain is used. * *************************************************************************/ Word16 d_gain_pitch ( /* out : quantized pitch gain */ struct EFR_decoder_state *st, Word16 index, /* in : index of quantization */ Word16 bfi, /* in : bad frame indicator (good = 0) */ Word16 state, Word16 prev_bf, Word16 rxdtx_ctrl ) { static const Word16 pdown[7] = { 32767, 32112, 32112, 26214, 9830, 6553, 6553 }; Word16 gain, tmp, i; if (bfi == 0) { if ((rxdtx_ctrl & RX_SP_FLAG) != 0) { gain = shr (qua_gain_pitch[index], 2); if (prev_bf != 0) { if (gain > st->prev_gp) { gain = st->prev_gp; } } } else { gain = 0; } st->prev_gp = gain; } else { if ((rxdtx_ctrl & RX_SP_FLAG) != 0) { tmp = gmed5 (st->pbuf); if (tmp < st->past_gain_pit) { st->past_gain_pit = tmp; } gain = mult (pdown[state], st->past_gain_pit); } else { gain = 0; } } st->past_gain_pit = gain; if (sub (st->past_gain_pit, 4096) > 0) /* if (past_gain_pit > 1.0) */ { st->past_gain_pit = 4096; } for (i = 1; i < 5; i++) { st->pbuf[i - 1] = st->pbuf[i]; } st->pbuf[4] = st->past_gain_pit; return gain; } /************************************************************************* * * FUNCTION: d_gain_code * * PURPOSE: decode the fixed codebook gain using the received index. * * DESCRIPTION: * The received index gives the gain correction factor gamma. * The quantized gain is given by g_q = g0 * gamma * where g0 is the predicted gain. * To find g0, 4th order MA prediction is applied to the mean-removed * innovation energy in dB. * In case of frame erasure, downscaled past gain is used. * *************************************************************************/ /* average innovation energy. */ /* MEAN_ENER = 36.0/constant, constant = 20*Log10(2) */ #define MEAN_ENER 783741L /* 36/(20*log10(2)) */ void d_gain_code ( struct EFR_decoder_state *st, Word16 index, /* input : received quantization index */ Word16 code[], /* input : innovation codevector */ Word16 lcode, /* input : codevector length */ Word16 *gain_code, /* output: decoded innovation gain */ Word16 bfi, /* input : bad frame indicator */ Word16 state, Word16 prev_bf, Word16 rxdtx_ctrl, Word16 i_subfr, Word16 rx_dtx_state ) { static const Word16 cdown[7] = { 32767, 32112, 32112, 32112, 32112, 32112, 22937 }; Word16 i, tmp; Word16 gcode0, exp, frac, av_pred_en; Word32 ener, ener_code; if (((rxdtx_ctrl & RX_UPD_SID_QUANT_MEM) != 0) && (i_subfr == 0)) { st->gcode0_CN = update_gcode0_CN (st->gain_code_old_rx); st->gcode0_CN = shl (st->gcode0_CN, 4); } /* Handle cases of comfort noise fixed codebook gain decoding in which past valid SID frames are repeated */ if (((rxdtx_ctrl & RX_NO_TRANSMISSION) != 0) || ((rxdtx_ctrl & RX_INVALID_SID_FRAME) != 0) || ((rxdtx_ctrl & RX_LOST_SID_FRAME) != 0)) { if ((rxdtx_ctrl & RX_NO_TRANSMISSION) != 0) { /* DTX active: no transmission. Interpolate gain values in memory */ if (i_subfr == 0) { *gain_code = interpolate_CN_param (st->gain_code_old_CN, st->gain_code_new_CN, rx_dtx_state); } else { *gain_code = st->prev_gc; } } else { /* Invalid or lost SID frame: use gain values from last good SID frame */ st->gain_code_old_CN = st->gain_code_new_CN; *gain_code = st->gain_code_new_CN; /* reset table of past quantized energies */ for (i = 0; i < 4; i++) { st->past_qua_en[i] = -2381; } } if ((rxdtx_ctrl & RX_DTX_MUTING) != 0) { /* attenuate the gain value by 0.75 dB in each subframe */ /* (total of 3 dB per frame) */ st->gain_code_muting_CN = mult (st->gain_code_muting_CN, 30057); *gain_code = st->gain_code_muting_CN; } else { /* Prepare for DTX muting by storing last good gain value */ st->gain_code_muting_CN = st->gain_code_new_CN; } st->past_gain_code = *gain_code; for (i = 1; i < 5; i++) { st->gbuf[i - 1] = st->gbuf[i]; } st->gbuf[4] = st->past_gain_code; st->prev_gc = st->past_gain_code; return; } /*----------------- Test erasure ---------------*/ if (bfi != 0) { tmp = gmed5 (st->gbuf); if (sub (tmp, st->past_gain_code) < 0) { st->past_gain_code = tmp; } st->past_gain_code = mult (st->past_gain_code, cdown[state]); *gain_code = st->past_gain_code; av_pred_en = 0; for (i = 0; i < 4; i++) { av_pred_en = add (av_pred_en, st->past_qua_en[i]); } /* av_pred_en = 0.25*av_pred_en - 4/(20Log10(2)) */ av_pred_en = mult (av_pred_en, 8192); /* *= 0.25 */ /* if (av_pred_en < -14/(20Log10(2))) av_pred_en = .. */ if (sub (av_pred_en, -2381) < 0) { av_pred_en = -2381; } for (i = 3; i > 0; i--) { st->past_qua_en[i] = st->past_qua_en[i - 1]; } st->past_qua_en[0] = av_pred_en; for (i = 1; i < 5; i++) { st->gbuf[i - 1] = st->gbuf[i]; } st->gbuf[4] = st->past_gain_code; /* Use the most recent comfort noise fixed codebook gain value for updating the fixed codebook gain history */ if (st->gain_code_new_CN == 0) { tmp = st->prev_gc; } else { tmp = st->gain_code_new_CN; } update_gain_code_history_rx (st, tmp); if (sub (i_subfr, (3 * L_SUBFR)) == 0) { st->gain_code_old_CN = *gain_code; } return; } if ((rxdtx_ctrl & RX_SP_FLAG) != 0) { /*-------------- Decode codebook gain ---------------*/ /*-------------------------------------------------------------------* * energy of code: * * ~~~~~~~~~~~~~~~ * * ener_code = 10 * Log10(energy/lcode) / constant * * = 1/2 * Log2(energy/lcode) * * constant = 20*Log10(2) * *-------------------------------------------------------------------*/ /* ener_code = log10(ener_code/lcode) / (20*log10(2)) */ ener_code = 0; move32 (); for (i = 0; i < lcode; i++) { ener_code = L_mac (ener_code, code[i], code[i]); } /* ener_code = ener_code / lcode */ ener_code = L_mult (round (ener_code), 26214); /* ener_code = 1/2 * Log2(ener_code) */ Log2 (ener_code, &exp, &frac); ener_code = L_Comp (sub (exp, 30), frac); /* predicted energy */ ener = MEAN_ENER; move32 (); for (i = 0; i < 4; i++) { ener = L_mac (ener, st->past_qua_en[i], st->pred[i]); } /*-------------------------------------------------------------------* * predicted codebook gain * * ~~~~~~~~~~~~~~~~~~~~~~~ * * gcode0 = Pow10( (ener*constant - ener_code*constant) / 20 ) * * = Pow2(ener-ener_code) * * constant = 20*Log10(2) * *-------------------------------------------------------------------*/ ener = L_shr (L_sub (ener, ener_code), 1); L_Extract (ener, &exp, &frac); gcode0 = extract_l (Pow2 (exp, frac)); /* predicted gain */ gcode0 = shl (gcode0, 4); *gain_code = mult (qua_gain_code[index], gcode0); move16 (); if (prev_bf != 0) { if (sub (*gain_code, st->prev_gc) > 0) { *gain_code = st->prev_gc; } } /*-------------------------------------------------------------------* * update table of past quantized energies * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * past_qua_en = 20 * Log10(qua_gain_code) / constant * * = Log2(qua_gain_code) * * constant = 20*Log10(2) * *-------------------------------------------------------------------*/ for (i = 3; i > 0; i--) { st->past_qua_en[i] = st->past_qua_en[i - 1]; } Log2 (L_deposit_l (qua_gain_code[index]), &exp, &frac); st->past_qua_en[0] = shr (frac, 5); st->past_qua_en[0] = add (st->past_qua_en[0], shl (sub (exp, 11), 10)); update_gain_code_history_rx (st, *gain_code); if (sub (i_subfr, (3 * L_SUBFR)) == 0) { st->gain_code_old_CN = *gain_code; } } else { if (((rxdtx_ctrl & RX_FIRST_SID_UPDATE) != 0) && (i_subfr == 0)) { st->gain_code_new_CN = mult (st->gcode0_CN, qua_gain_code[index]); /*---------------------------------------------------------------* * reset table of past quantized energies * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * *---------------------------------------------------------------*/ for (i = 0; i < 4; i++) { st->past_qua_en[i] = -2381; } } if (((rxdtx_ctrl & RX_CONT_SID_UPDATE) != 0) && (i_subfr == 0)) { st->gain_code_old_CN = st->gain_code_new_CN; st->gain_code_new_CN = mult (st->gcode0_CN, qua_gain_code[index]); } if (i_subfr == 0) { *gain_code = interpolate_CN_param (st->gain_code_old_CN, st->gain_code_new_CN, rx_dtx_state); } else { *gain_code = st->prev_gc; } } st->past_gain_code = *gain_code; for (i = 1; i < 5; i++) { st->gbuf[i - 1] = st->gbuf[i]; } st->gbuf[4] = st->past_gain_code; st->prev_gc = st->past_gain_code; return; }