c_g_aver.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/c_g_aver.c
 Functions:
            Cb_gain_average_reset
            Cb_gain_average

     Date: 03/28/2000

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

 Description: Made some changes to the comments to match the comments from
    other modules.

 Description: Made changes based on comments from the review meeting.

 Description: Synchronized file with UMTS version 3.2.0. Updated coding
              template.

 Description: Made the following changes per comments from Phase 2/3 review:
              1. Defined one local variable per line.

 Description: Removed the functions Cb_gain_average_init and
 Cb_gain_average_exit.  The Cb_gain_average related structure is no longer
 dynamically allocated.

 Description: Passing in pOverflow to comply with changes needed for EPOC
              Updated the include files for the module.

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


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

 Description:
------------------------------------------------------------------------------
 MODULE DESCRIPTION

 This file contains functions that reset and perform
 codebook gain calculations.

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


/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include    "c_g_aver.h"
#include    "typedef.h"
#include    "mode.h"
#include    "cnst.h"

#include    "basic_op.h"
#include    "oscl_mem.h"

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


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

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

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

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

 Inputs:
    state = pointer to a structure of type Cb_gain_averageState

 Outputs:
    Structure pointed to by state is initialized to zeros

 Returns:
    Returns 0 if memory was successfully initialized,
        otherwise returns -1.

 Global Variables Used:
    None.

 Local Variables Needed:
    None.

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

 Resets state memory

------------------------------------------------------------------------------
 REQUIREMENTS

 None.

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

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

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

Word16 Cb_gain_average_reset (Cb_gain_averageState *state)
{
   if (state == (Cb_gain_averageState *) NULL){
      fprintf(stderr, "Cb_gain_average_reset: invalid parameter\n");
      return -1;
   }

   // Static vectors to zero
   Set_zero (state->cbGainHistory, L_CBGAINHIST);

   // Initialize hangover handling
   state->hangVar = 0;
   state->hangCount= 0;

   return 0;
}

------------------------------------------------------------------------------
 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]

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

Word16  Cb_gain_average_reset(Cb_gain_averageState *state)
{
    if (state == (Cb_gain_averageState *) NULL)
    {
        /* fprint(stderr, "Cb_gain_average_reset: invalid parameter\n");  */
        return(-1);
    }

    /* Static vectors to zero */
    oscl_memset(state->cbGainHistory, 0, L_CBGAINHIST*sizeof(Word16));

    /* Initialize hangover handling */
    state->hangVar = 0;
    state->hangCount = 0;

    return(0);
}

/****************************************************************************/

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

 Inputs:
    st = pointer to structure of type Cb_gain_averageState
    mode = AMR mode (enum Mode)
    gain_code = CB gain (Word16)
    lsp = the LSP for the current frame (Word16)
    lspAver = the average of LSP for 8 frames (Word16)
    bfi = bad frame indication flag (Word16)
    prev_bf = previous bad frame indication flag (Word16)
    pdfi = potential degraded bad frame ind flag (Word16)
    prev_pdf = prev pot. degraded bad frame ind flag (Word16)
    inBackgroundNoise = background noise decision (Word16)
    voicedHangover = # of frames after last voiced frame (Word16)
    pOverflow = address of overflow (Flag)

 Returns:
    cbGainMix = codebook gain (Word16)

 Outputs:
    None.

 Global Variables Used:
    None.

 Local Variables Needed:
    None.

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

 The mix cb gains for MR475, MR515, MR59, MR67, MR102; gain_code other modes

------------------------------------------------------------------------------
 REQUIREMENTS

 None.

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

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

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

Word16 Cb_gain_average (
   Cb_gain_averageState *st, // i/o : State variables for CB gain avergeing
   enum Mode mode,           // i   : AMR mode
   Word16 gain_code,         // i   : CB gain                              Q1
   Word16 lsp[],             // i   : The LSP for the current frame       Q15
   Word16 lspAver[],         // i   : The average of LSP for 8 frames     Q15
   Word16 bfi,               // i   : bad frame indication flag
   Word16 prev_bf,           // i   : previous bad frame indication flag
   Word16 pdfi,              // i   : potential degraded bad frame ind flag
   Word16 prev_pdf,          // i   : prev pot. degraded bad frame ind flag
   Word16 inBackgroundNoise, // i   : background noise decision
   Word16 voicedHangover     // i   : # of frames after last voiced frame
   )
{
   //---------------------------------------------------------*
    * Compute mixed cb gain, used to make cb gain more        *
    * smooth in background noise for modes 5.15, 5.9 and 6.7  *
    * states that needs to be updated by all                  *
    *---------------------------------------------------------
   Word16 i;
   Word16 cbGainMix, diff, tmp_diff, bgMix, cbGainMean;
   Word32 L_sum;
   Word16 tmp[M], tmp1, tmp2, shift1, shift2, shift;

   // set correct cbGainMix for MR74, MR795, MR122
   cbGainMix = gain_code;

    *-------------------------------------------------------*
    *   Store list of CB gain needed in the CB gain         *
    *   averaging                                           *
    *-------------------------------------------------------*
   for (i = 0; i < (L_CBGAINHIST-1); i++)
   {
      st->cbGainHistory[i] = st->cbGainHistory[i+1];
   }
   st->cbGainHistory[L_CBGAINHIST-1] = gain_code;

   // compute lsp difference
   for (i = 0; i < M; i++) {
      tmp1 = abs_s(sub(lspAver[i], lsp[i]));  // Q15
      shift1 = sub(norm_s(tmp1), 1);          // Qn
      tmp1 = shl(tmp1, shift1);               // Q15+Qn
      shift2 = norm_s(lspAver[i]);            // Qm
      tmp2 = shl(lspAver[i], shift2);         // Q15+Qm
      tmp[i] = div_s(tmp1, tmp2);             // Q15+(Q15+Qn)-(Q15+Qm)
      shift = sub(add(2, shift1), shift2);
      if (shift >= 0)
      {
         tmp[i] = shr(tmp[i], shift); // Q15+Qn-Qm-Qx=Q13
      }
      else
      {
         tmp[i] = shl(tmp[i], negate(shift)); // Q15+Qn-Qm-Qx=Q13
      }
   }

   diff = tmp[0];
   for (i = 1; i < M; i++) {
      diff = add(diff, tmp[i]);       // Q13
   }

   // Compute hangover