FreeCalypso > hg > gsm-codec-lib
view libtwamr/gain_q.c @ 581:e2d5cad04cbf
libgsmhr1 RxFE: store CN R0+LPC separately from speech
In the original GSM 06.06 code the ECU for speech mode is entirely
separate from the CN generator, maintaining separate state. (The
main intertie between them is the speech vs CN state variable,
distinguishing between speech and CN BFIs, in addition to the
CN-specific function of distinguishing between initial and update
SIDs.)
In the present RxFE implementation I initially thought that we could
use the same saved_frame buffer for both ECU and CN, overwriting
just the first 4 params (R0 and LPC) when a valid SID comes in.
However, I now realize it was a bad idea: the original code has a
corner case (long sequence of speech-mode BFIs to put the ECU in
state 6, then SID and CN-mode BFIs, then a good speech frame) that
would be broken by that buffer reuse approach. We could eliminate
this corner case by resetting the ECU state when passing through
a CN insertion period, but doing so would needlessly increase
the behavioral diffs between GSM 06.06 and our version.
Solution: use a separate CN-specific buffer for CN R0+LPC parameters,
and match the behavior of GSM 06.06 code in this regard.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 13 Feb 2025 10:02:45 +0000 |
| parents | ccba5812fa44 |
| 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 : gain_q.c * Purpose : Quantazation of gains * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "gain_q.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "tw_amr.h" #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "qua_gain.h" #include "cnst.h" #include "g_code.h" #include "q_gain_c.h" #include "gc_pred.h" #include "calc_en.h" #include "qgain795.h" #include "qgain475.h" #include "memops.h" /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /************************************************************************* * * Function: gainQuant_reset * Purpose: Initializes state memory to zero * ************************************************************************** */ void gainQuant_reset (gainQuantState *state) { state->sf0_exp_gcode0 = 0; state->sf0_frac_gcode0 = 0; state->sf0_exp_target_en = 0; state->sf0_frac_target_en = 0; Set_zero (state->sf0_exp_coeff, 5); Set_zero (state->sf0_frac_coeff, 5); gc_pred_reset(&state->gc_predSt); gc_pred_reset(&state->gc_predUnqSt); gain_adapt_reset(&state->adaptSt); } int gainQuant( gainQuantState *st, /* i/o : State struct */ enum Mode mode, /* i : coder mode */ Word16 res[], /* i : LP residual, Q0 */ Word16 exc[], /* i : LTP excitation (unfiltered), Q0 */ Word16 code[], /* i : CB innovation (unfiltered), Q13 */ /* (unsharpened for MR475) */ Word16 xn[], /* i : Target vector. */ Word16 xn2[], /* i : Target vector. */ Word16 y1[], /* i : Adaptive codebook. */ Word16 Y2[], /* i : Filtered innovative vector. */ Word16 g_coeff[], /* i : Correlations <xn y1> <y1 y1> */ /* Compute in G_pitch(). */ Word16 even_subframe, /* i : even subframe indicator flag */ Word16 gp_limit, /* i : pitch gain limit */ Word16 *sf0_gain_pit, /* o : Pitch gain sf 0. MR475 */ Word16 *sf0_gain_cod, /* o : Code gain sf 0. MR475 */ Word16 *gain_pit, /* i/o : Pitch gain. */ Word16 *gain_cod, /* o : Code gain. */ /* MR475: gain_* unquantized in even */ /* subframes, quantized otherwise */ Word16 **anap /* o : Index of quantization */ ) { Word16 exp_gcode0; Word16 frac_gcode0; Word16 qua_ener_MR122; Word16 qua_ener; Word16 frac_coeff[5]; Word16 exp_coeff[5]; Word16 exp_en, frac_en; Word16 cod_gain_exp, cod_gain_frac; test (); if (sub (mode, MR475) == 0) { test (); if (even_subframe != 0) { /* save position in output parameter stream and current state of codebook gain predictor */ st->gain_idx_ptr = (*anap)++; gc_pred_copy(&st->gc_predSt, &st->gc_predUnqSt); /* predict codebook gain (using "unquantized" predictor)*/ /* (note that code[] is unsharpened in MR475) */ gc_pred(&st->gc_predUnqSt, mode, code, &st->sf0_exp_gcode0, &st->sf0_frac_gcode0, &exp_en, &frac_en); /* calculate energy coefficients for quantization and store them in state structure (will be used in next subframe when real quantizer is run) */ calc_filt_energies(mode, xn, xn2, y1, Y2, g_coeff, st->sf0_frac_coeff, st->sf0_exp_coeff, &cod_gain_frac, &cod_gain_exp); /* store optimum codebook gain (Q1) */ *gain_cod = shl (cod_gain_frac, add (cod_gain_exp, 1)); move16 (); calc_target_energy(xn, &st->sf0_exp_target_en, &st->sf0_frac_target_en); /* calculate optimum codebook gain and update "unquantized" predictor */ MR475_update_unq_pred(&st->gc_predUnqSt, st->sf0_exp_gcode0, st->sf0_frac_gcode0, cod_gain_exp, cod_gain_frac); /* the real quantizer is not run here... */ } else { /* predict codebook gain (using "unquantized" predictor) */ /* (note that code[] is unsharpened in MR475) */ gc_pred(&st->gc_predUnqSt, mode, code, &exp_gcode0, &frac_gcode0, &exp_en, &frac_en); /* calculate energy coefficients for quantization */ calc_filt_energies(mode, xn, xn2, y1, Y2, g_coeff, frac_coeff, exp_coeff, &cod_gain_frac, &cod_gain_exp); calc_target_energy(xn, &exp_en, &frac_en); /* run real (4-dim) quantizer and update real gain predictor */ *st->gain_idx_ptr = MR475_gain_quant( &st->gc_predSt, st->sf0_exp_gcode0, st->sf0_frac_gcode0, st->sf0_exp_coeff, st->sf0_frac_coeff, st->sf0_exp_target_en, st->sf0_frac_target_en, code, exp_gcode0, frac_gcode0, exp_coeff, frac_coeff, exp_en, frac_en, gp_limit, sf0_gain_pit, sf0_gain_cod, gain_pit, gain_cod); } } else { /*-------------------------------------------------------------------* * predict codebook gain and quantize * * (also compute normalized CB innovation energy for MR795) * *-------------------------------------------------------------------*/ gc_pred(&st->gc_predSt, mode, code, &exp_gcode0, &frac_gcode0, &exp_en, &frac_en); test (); if (sub(mode, MR122) == 0) { *gain_cod = G_code (xn2, Y2); move16 (); *(*anap)++ = q_gain_code (mode, exp_gcode0, frac_gcode0, gain_cod, &qua_ener_MR122, &qua_ener); move16 (); } else { /* calculate energy coefficients for quantization */ calc_filt_energies(mode, xn, xn2, y1, Y2, g_coeff, frac_coeff, exp_coeff, &cod_gain_frac, &cod_gain_exp); test (); if (sub (mode, MR795) == 0) { MR795_gain_quant(&st->adaptSt, res, exc, code, frac_coeff, exp_coeff, exp_en, frac_en, exp_gcode0, frac_gcode0, L_SUBFR, cod_gain_frac, cod_gain_exp, gp_limit, gain_pit, gain_cod, &qua_ener_MR122, &qua_ener, anap); } else { *(*anap)++ = Qua_gain(mode, exp_gcode0, frac_gcode0, frac_coeff, exp_coeff, gp_limit, gain_pit, gain_cod, &qua_ener_MR122, &qua_ener); move16 (); } } /*------------------------------------------------------------------* * update table of past quantized energies * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * st->past_qua_en(Q10) = 20 * Log10(qua_gain_code) / constant * * = Log2(qua_gain_code) * * = qua_ener * * constant = 20*Log10(2) * *------------------------------------------------------------------*/ gc_pred_update(&st->gc_predSt, qua_ener_MR122, qua_ener); } return 0; }