FreeCalypso > hg > gsm-codec-lib
view libtwamr/dec_gain.c @ 406:85e9768d497f
libtwamr: integrate cl_ltp.c
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Mon, 06 May 2024 23:32:59 +0000 |
parents | 5ccfe176bae1 |
children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : dec_gain.c * Purpose : Decode the pitch and codebook gains * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "dec_gain.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include <stddef.h> #include "tw_amr.h" #include "typedef.h" #include "basic_op.h" #include "oper_32b.h" #include "no_count.h" #include "cnst.h" #include "pow2.h" #include "log2.h" #include "gc_pred.h" #include "qua_gain_tab.h" /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /************************************************************************* * * FUNCTION: Dec_gain() * * PURPOSE: Decode the pitch and codebook gains * ************************************************************************/ void Dec_gain( gc_predState *pred_state, /* i/o: MA predictor state */ enum Mode mode, /* i : AMR mode */ Word16 index, /* i : index of quantization. */ Word16 code[], /* i : Innovative vector. */ Word16 evenSubfr, /* i : Flag for even subframes */ Word16 * gain_pit, /* o : Pitch gain. */ Word16 * gain_cod /* o : Code gain. */ ) { const Word16 *p; Word16 frac, gcode0, exp, qua_ener, qua_ener_MR122; Word16 g_code; Word32 L_tmp; /* Read the quantized gains (table depends on mode) */ index = shl (index, 2); test(); test(); test(); if ( sub (mode, MR102) == 0 || sub (mode, MR74) == 0 || sub (mode, MR67) == 0) { p = &table_gain_highrates[index]; move16 (); *gain_pit = *p++; move16 (); g_code = *p++; move16 (); qua_ener_MR122 = *p++; move16 (); qua_ener = *p; move16 (); } else { test(); if (sub (mode, MR475) == 0) { index = add (index, shl(sub(1, evenSubfr), 1)); p = &table_gain_MR475[index]; move16 (); *gain_pit = *p++; move16 (); g_code = *p++; move16 (); /*---------------------------------------------------------* * calculate predictor update values (not stored in 4.75 * * quantizer table to save space): * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * * * qua_ener = log2(g) * * qua_ener_MR122 = 20*log10(g) * *---------------------------------------------------------*/ /* Log2(x Q12) = log2(x) + 12 */ Log2 (L_deposit_l (g_code), &exp, &frac); exp = sub(exp, 12); qua_ener_MR122 = add (shr_r (frac, 5), shl (exp, 10)); /* 24660 Q12 ~= 6.0206 = 20*log10(2) */ L_tmp = Mpy_32_16(exp, frac, 24660); qua_ener = round (L_shl (L_tmp, 13)); /* Q12 * Q0 = Q13 -> Q10 */ } else { p = &table_gain_lowrates[index]; move16 (); *gain_pit = *p++; move16 (); g_code = *p++; move16 (); qua_ener_MR122 = *p++; move16 (); qua_ener = *p; move16 (); } } /*-------------------------------------------------------------------* * predict codebook gain * * ~~~~~~~~~~~~~~~~~~~~~ * * gc0 = Pow2(int(d)+frac(d)) * * = 2^exp + 2^frac * * * * gcode0 (Q14) = 2^14*2^frac = gc0 * 2^(14-exp) * *-------------------------------------------------------------------*/ gc_pred(pred_state, mode, code, &exp, &frac, NULL, NULL); gcode0 = extract_l(Pow2(14, frac)); /*------------------------------------------------------------------* * read quantized gains, update table of past quantized energies * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * st->past_qua_en(Q10) = 20 * Log10(g_fac) / constant * * = Log2(g_fac) * * = qua_ener * * constant = 20*Log10(2) * *------------------------------------------------------------------*/ L_tmp = L_mult(g_code, gcode0); L_tmp = L_shr(L_tmp, sub(10, exp)); *gain_cod = extract_h(L_tmp); /* update table of past quantized energies */ gc_pred_update(pred_state, qua_ener_MR122, qua_ener); return; }