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/* ------------------------------------------------------------------
* Copyright (C) 1998-2009 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/dec_gain.c
Funtions: dec_gain
Date: 01/31/2002
------------------------------------------------------------------------------
REVISION HISTORY
Description: Updating include file lists, and other things as per review
comments.
Description: Added fixes to the code as per review comments. Removed nested
function calls and declared temp2 as a variable.
Description: A Word32 was being stored improperly in a Word16.
Description: Removed qua_gain.tab and qgain475.tab from Include section and
added qua_gain_tbl.h and qgain475_tab.h to Include section.
Description: Changed round function name to pv_round to avoid conflict with
round function in C standard library.
Description: Added casting to eliminate warnings
Description: Replaced "int" and/or "char" with OSCL defined types.
Description:
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "dec_gain.h"
#include "typedef.h"
#include "mode.h"
#include "cnst.h"
#include "pow2.h"
#include "log2.h"
#include "gc_pred.h"
#include "basic_op.h"
#include "qua_gain_tbl.h"
#include "qgain475_tab.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: dec_gain
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
pred_state = pointer to MA predictor state of type gc_predState
index = AMR mode of type enum Mode
code[] = pointer to innovative vector of type Word16
evenSubfr = Flag for even subframes of type Word16
pOverflow = pointer to overflow flag
Outputs:
pred_state = pointer to MA predictor state of type gc_predState
gain_pit = pointer to pitch gain of type Word16
gain_cod = pointer to code gain of type Word16
Returns:
None.
Global Variables Used:
None.
Local Variables Needed:
None.
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
File : dec_gain.c
Purpose : Decode the pitch and codebook gains
------------------------------------------------------------------------------
REQUIREMENTS
None.
------------------------------------------------------------------------------
REFERENCES
agc.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]
------------------------------------------------------------------------------
*/
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. */
Flag * pOverflow
)
{
const Word16 *p;
Word16 frac;
Word16 gcode0;
Word16 exp;
Word16 qua_ener;
Word16 qua_ener_MR122;
Word16 g_code;
Word32 L_tmp;
Word16 temp1;
Word16 temp2;
/* Read the quantized gains (table depends on mode) */
index = shl(index, 2, pOverflow);
if (mode == MR102 || mode == MR74 || mode == MR67)
{
p = &table_gain_highrates[index];
*gain_pit = *p++;
g_code = *p++;
qua_ener_MR122 = *p++;
qua_ener = *p;
}
else
{
if (mode == MR475)
{
index += (1 ^ evenSubfr) << 1; /* evenSubfr is 0 or 1 */
if (index > (MR475_VQ_SIZE*4 - 2))
{
index = (MR475_VQ_SIZE * 4 - 2); /* avoid possible buffer overflow */
}
p = &table_gain_MR475[index];
*gain_pit = *p++;
g_code = *p++;
/*---------------------------------------------------------*
* 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 */
temp1 = (Word16) L_deposit_l(g_code);
Log2(temp1, &exp, &frac, pOverflow);
exp = sub(exp, 12, pOverflow);
temp1 = shr_r(frac, 5, pOverflow);
temp2 = shl(exp, 10, pOverflow);
qua_ener_MR122 = add(temp1, temp2, pOverflow);
/* 24660 Q12 ~= 6.0206 = 20*log10(2) */
L_tmp = Mpy_32_16(exp, frac, 24660, pOverflow);
L_tmp = L_shl(L_tmp, 13, pOverflow);
qua_ener = pv_round(L_tmp, pOverflow);
/* Q12 * Q0 = Q13 -> Q10 */
}
else
{
p = &table_gain_lowrates[index];
*gain_pit = *p++;
g_code = *p++;
qua_ener_MR122 = *p++;
qua_ener = *p;
}
}
/*-------------------------------------------------------------------*
* 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, pOverflow);
gcode0 = (Word16) Pow2(14, frac, pOverflow);
/*------------------------------------------------------------------*
* 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, pOverflow);
temp1 = sub(10, exp, pOverflow);
L_tmp = L_shr(L_tmp, temp1, pOverflow);
*gain_cod = extract_h(L_tmp);
/* update table of past quantized energies */
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
return;
}
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