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view libtwamr/qgain795.h @ 581:e2d5cad04cbf

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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 2aa98051d445
children
line wrap: on
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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             : qgain795.h
*      Purpose          : (pre-) quantization of pitch gain for MR795
*
********************************************************************************
*/
#ifndef qgain795_h
#define qgain795_h "$Id $"
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
#include "g_adapt.h"

/*
********************************************************************************
*                         DECLARATION OF PROTOTYPES
********************************************************************************
*/

/*************************************************************************
 *
 * FUNCTION:  MR795_gain_quant
 *
 * PURPOSE:   pitch and codebook quantization for MR795
 *
 *************************************************************************/
void
MR795_gain_quant(
    GainAdaptState *adapt_st, /* i/o: gain adapter state structure       */
    Word16 res[],             /* i  : LP residual,                  Q0   */
    Word16 exc[],             /* i  : LTP excitation (unfiltered),  Q0   */
    Word16 code[],            /* i  : CB innovation (unfiltered),   Q13  */
    Word16 frac_coeff[],      /* i  : coefficients (5),             Q15  */
    Word16 exp_coeff[],       /* i  : energy coefficients (5),      Q0   */
                              /*      coefficients from calc_filt_ener() */
    Word16 exp_code_en,       /* i  : innovation energy (exponent), Q0   */
    Word16 frac_code_en,      /* i  : innovation energy (fraction), Q15  */
    Word16 exp_gcode0,        /* i  : predicted CB gain (exponent), Q0   */
    Word16 frac_gcode0,       /* i  : predicted CB gain (fraction), Q15  */
    Word16 L_subfr,           /* i  : Subframe length                    */
    Word16 cod_gain_frac,     /* i  : opt. codebook gain (fraction),Q15  */
    Word16 cod_gain_exp,      /* i  : opt. codebook gain (exponent), Q0  */
    Word16 gp_limit,          /* i  : pitch gain limit                   */
    Word16 *gain_pit,         /* i/o: Pitch gain (unquant/quant),   Q14  */
    Word16 *gain_cod,         /* o  : Code gain,                    Q1   */
    Word16 *qua_ener_MR122,   /* o  : quantized energy error,       Q10  */
                              /*      (for MR122 MA predictor update)    */
    Word16 *qua_ener,         /* o  : quantized energy error,       Q10  */
                              /*      (for other MA predictor update)    */
    Word16 **anap             /* o  : Index of quantization              */
                              /*      (first gain pitch, then code pitch)*/
);

#endif