qgain795.cpp

实现3GPP的GSM中AMR语音的CODECS。

/* ------------------------------------------------------------------
 * Copyright (C) 2008 PacketVideo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 * -------------------------------------------------------------------
 */
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:

    3GPP TS 26.073
    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
    Available from http://www.3gpp.org

(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
------------------------------------------------------------------------------



 Pathname: ./audio/gsm-amr/c/src/qgain795.c
 Functions: MR795_gain_code_quant3
            MR795_gain_code_quant_mod
            MR795_gain_quant

     Date: 02/04/2002

------------------------------------------------------------------------------
 REVISION HISTORY

 Description: Updated template used to PV coding template.
 Changed to accept the pOverflow flag for EPOC compatibility.

 Description:
 (1) Removed optimization -- mult(i, 3, pOverflow) is NOT the same as adding
     i to itself 3 times.  The reason is because the mult function does a
     right shift by 15, which will obliterate smaller numbers.

 Description:  Replaced OSCL mem type functions and eliminated include
               files that now are chosen by OSCL definitions

 Description:  Replaced "int" and/or "char" with OSCL defined types.

 Description: Changed round function name to pv_round to avoid conflict with
              round function in C standard library.

 Description: Added #ifdef __cplusplus around extern'ed table.

 Description:

------------------------------------------------------------------------------
 MODULE DESCRIPTION


------------------------------------------------------------------------------
*/

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "qgain795.h"
#include "typedef.h"
#include "basic_op.h"
#include "cnst.h"
#include "log2.h"
#include "pow2.h"
#include "sqrt_l.h"
#include "g_adapt.h"
#include "calc_en.h"
#include "q_gain_p.h"


/*--------------------------------------------------------------------------*/
#ifdef __cplusplus
extern "C"
{
#endif

    /*----------------------------------------------------------------------------
    ; MACROS
    ; Define module specific macros here
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; DEFINES
    ; Include all pre-processor statements here. Include conditional
    ; compile variables also.
    ----------------------------------------------------------------------------*/
#define NB_QUA_CODE 32

    /*----------------------------------------------------------------------------
    ; LOCAL FUNCTION DEFINITIONS
    ; Function Prototype declaration
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; LOCAL VARIABLE DEFINITIONS
    ; Variable declaration - defined here and used outside this module
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
    ; Declare variables used in this module but defined elsewhere
    ----------------------------------------------------------------------------*/
    extern const Word16 qua_gain_code[NB_QUA_CODE*3];


    /*--------------------------------------------------------------------------*/
#ifdef __cplusplus
}
#endif

/*
------------------------------------------------------------------------------
 FUNCTION NAME: MR795_gain_code_quant3
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    exp_gcode0     -- Word16       -- predicted CB gain (exponent), Q0
    gcode0         -- Word16       -- predicted CB gain (norm.)
    g_pitch_cand[] -- Word16 array -- Pitch gain candidates (3),    Q14
    g_pitch_cind[] -- Word16 array -- Pitch gain cand. indices (3), Q0
    frac_coeff[]   -- Word16 array -- coefficients (5),             Q15
    exp_coeff[]    -- Word16 array -- energy coefficients (5),      Q0
                                      coefficients from calc_filt_ener()

 Outputs:
    gain_pit       -- Pointer to Word16 -- Pitch gain,                     Q14
    gain_pit_ind   -- Pointer to Word16 -- Pitch gain index,               Q0
    gain_cod       -- Pointer to Word16 -- Code gain,                      Q1
    gain_cod_ind   -- Pointer to Word16 -- Code gain index,                Q0
    qua_ener_MR122 -- Pointer to Word16 -- quantized energy error,         Q10
                                          (for MR122 MA predictor update)

    qua_ener -- Pointer to Word16 -- quantized energy error,       Q10
                                     (for other MA predictor update)

    pOverflow -- Pointer to Flag --  overflow indicator

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION

 PURPOSE: Pre-quantization of codebook gains, given three possible
          LTP gains (using predicted codebook gain)
------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 qgain795.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

------------------------------------------------------------------------------
 PSEUDO-CODE


------------------------------------------------------------------------------
 RESOURCES USED [optional]

 When the code is written for a specific target processor the
 the resources used should be documented below.

 HEAP MEMORY USED: x bytes

 STACK MEMORY USED: x bytes

 CLOCK CYCLES: (cycle count equation for this function) + (variable
                used to represent cycle count for each subroutine
                called)
     where: (cycle count variable) = cycle count for [subroutine
                                     name]

------------------------------------------------------------------------------
 CAUTION [optional]
 [State any special notes, constraints or cautions for users of this function]

------------------------------------------------------------------------------
*/

static void
MR795_gain_code_quant3(
    Word16 exp_gcode0,        /* i  : predicted CB gain (exponent), Q0  */
    Word16 gcode0,            /* i  : predicted CB gain (norm.),    Q14 */
    Word16 g_pitch_cand[],    /* i  : Pitch gain candidates (3),    Q14 */
    Word16 g_pitch_cind[],    /* i  : Pitch gain cand. indices (3), Q0  */
    Word16 frac_coeff[],      /* i  : coefficients (5),             Q15 */
    Word16 exp_coeff[],       /* i  : energy coefficients (5),      Q0  */
    /*      coefficients from calc_filt_ener()*/
    Word16 *gain_pit,         /* o  : Pitch gain,                   Q14 */
    Word16 *gain_pit_ind,     /* o  : Pitch gain index,             Q0  */
    Word16 *gain_cod,         /* o  : Code gain,                    Q1  */
    Word16 *gain_cod_ind,     /* o  : Code gain index,              Q0  */
    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)   */
    Flag   *pOverflow         /* o  : overflow indicator                */
)
{
    const Word16 *p;
    Word16 i;
    Word16 j;
    Word16 cod_ind;
    Word16 pit_ind;
    Word16 e_max;
    Word16 exp_code;
    Word16 g_pitch;
    Word16 g2_pitch;
    Word16 g_code;
    Word16 g2_code_h;
    Word16 g2_code_l;
    Word16 g_pit_cod_h;
    Word16 g_pit_cod_l;
    Word16 coeff[5];
    Word16 coeff_lo[5];
    Word16 exp_max[5];
    Word32 L_tmp;
    Word32 L_tmp0;
    Word32 dist_min;

    /*
     * The error energy (sum) to be minimized consists of five terms, t[0..4].
     *
     *                      t[0] =    gp^2  * <y1 y1>
     *                      t[1] = -2*gp    * <xn y1>
     *                      t[2] =    gc^2  * <y2 y2>
     *                      t[3] = -2*gc    * <xn y2>
     *                      t[4] =  2*gp*gc * <y1 y2>
     *
     */

    /* determine the scaling exponent for g_code: ec = ec0 - 10 */
    exp_code = sub(exp_gcode0, 10, pOverflow);

    /* calculate exp_max[i] = s[i]-1 */
    exp_max[0] = sub(exp_coeff[0], 13, pOverflow);
    exp_max[1] = sub(exp_coeff[1], 14, pOverflow);
    exp_max[2] = add(exp_coeff[2], add(15, shl(exp_code, 1, pOverflow), pOverflow), pOverflow);
    exp_max[3] = add(exp_coeff[3], exp_code, pOverflow);
    exp_max[4] = add(exp_coeff[4], add(exp_code, 1, pOverflow), pOverflow);


    /*-------------------------------------------------------------------*
     *  Find maximum exponent:                                           *
     *  ~~~~~~~~~~~~~~~~~~~~~~                                           *
     *                                                                   *
     *  For the sum operation, all terms must have the same scaling;     *
     *  that scaling should be low enough to prevent overflow. There-    *
     *  fore, the maximum scale is determined and all coefficients are   *
     *  re-scaled:                                                       *
     *                                                                   *
     *    e_max = max(exp_max[i]) + 1;                                   *
     *    e = exp_max[i]-e_max;         e <= 0!                          *
     *    c[i] = c[i]*2^e                                                *
     *-------------------------------------------------------------------*/

    e_max = exp_max[0];
    for (i = 1; i < 5; i++)     /* implemented flattened */
    {
        if (exp_max[i] > e_max)
        {
            e_max = exp_max[i];
        }
    }

    e_max = add(e_max, 1, pOverflow);      /* To avoid overflow */

    for (i = 0; i < 5; i++)
    {
        j = sub(e_max, exp_max[i], pOverflow);
        L_tmp = L_deposit_h(frac_coeff[i]);
        L_tmp = L_shr(L_tmp, j, pOverflow);
        L_Extract(L_tmp, &coeff[i], &coeff_lo[i], pOverflow);
    }


    /*-------------------------------------------------------------------*