/*----------------------------------------------------------------------------
; FUNCTION CODE
----------------------------------------------------------------------------*/
void d_gain_code(
gc_predState *pred_state, /* i/o : MA predictor state */
enum Mode mode, /* i : AMR mode (MR795 or MR122) */
Word16 index, /* i : received quantization index */
Word16 code[], /* i : innovation codevector */
Word16 *gain_code, /* o : decoded innovation gain */
Flag *pOverflow
)
{
Word16 gcode0, exp, frac;
const Word16 *p;
Word16 qua_ener_MR122, qua_ener;
Word16 exp_inn_en;
Word16 frac_inn_en;
Word32 L_tmp;
Word16 tbl_tmp;
Word16 temp;
/*-------------- Decode codebook gain ---------------*/
/*-------------------------------------------------------------------*
* predict codebook gain *
* ~~~~~~~~~~~~~~~~~~~~~ *
* gc0 = Pow2(int(d)+frac(d)) *
* = 2^exp + 2^frac *
* *
*-------------------------------------------------------------------*/
gc_pred(pred_state, mode, code, &exp, &frac,
&exp_inn_en, &frac_inn_en, pOverflow);
tbl_tmp = add(add(index, index, pOverflow), index, pOverflow);
p = &qua_gain_code[tbl_tmp];
/* Different scalings between MR122 and the other modes */
temp = sub((Word16)mode, (Word16)MR122, pOverflow);
if (temp == 0)
{
gcode0 = (Word16)(Pow2(exp, frac, pOverflow)); /* predicted gain */
gcode0 = shl(gcode0, 4, pOverflow);
*gain_code = shl(mult(gcode0, *p++, pOverflow), 1, pOverflow);
}
else
{
gcode0 = (Word16)(Pow2(14, frac, pOverflow));
L_tmp = L_mult(*p++, gcode0, pOverflow);
L_tmp = L_shr(L_tmp, sub(9, exp, pOverflow), pOverflow);
*gain_code = extract_h(L_tmp); /* Q1 */
}
/*-------------------------------------------------------------------*
* update table of past quantized energies *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
*-------------------------------------------------------------------*/
qua_ener_MR122 = *p++;
qua_ener = *p++;
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
return;
}
/*
------------------------------------------------------------------------------
FUNCTION NAME: ec_gain_code
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
st = pointer to a pointer to a structure containing code state data of
stucture type ec_gain_codeState
pred_state = pointer to MA predictor state of type gc_predState
state = state of the state machine of type Word16
gain_code = pointer to decoded innovation gain of type Word16
pOverflow = pointer to overflow indicator of type Flag
Outputs:
st = pointer to a pointer to a structure containing code state data of
stucture type ec_gain_codeState
pred_state = pointer to MA predictor state of type gc_predState
pOverflow = 1 if there is an overflow else it is zero.
Returns:
None.
Global Variables Used:
None.
Local Variables Needed:
None.
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function does error concealment using the codebook. Call this function
only in BFI (instead of normal gain decoding function).
------------------------------------------------------------------------------
REQUIREMENTS
None.
------------------------------------------------------------------------------
REFERENCES
ec_gain.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
static const Word16 cdown[7] =
{
32767, 32112, 32112, 32112,
32112, 32112, 22937
};
Word16 tmp;
Word16 qua_ener_MR122;
Word16 qua_ener;
// calculate median of last five gain values
tmp = gmed_n (st->gbuf,5);
// new gain = minimum(median, past_gain) * cdown[state]
if (sub (tmp, st->past_gain_code) > 0)
{
tmp = st->past_gain_code;
}
tmp = mult (tmp, cdown[state]);
*gain_code = tmp;
// update table of past quantized energies with average of
// current values
gc_pred_average_limited(pred_state, &qua_ener_MR122, &qua_ener);
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
}
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
void ec_gain_code(
ec_gain_codeState *st, /* i/o : State struct */
gc_predState *pred_state, /* i/o : MA predictor state */
Word16 state, /* i : state of the state machine */
Word16 *gain_code, /* o : decoded innovation gain */
Flag *pOverflow
)
{
static const Word16 cdown[7] =
{
32767, 32112, 32112, 32112,
32112, 32112, 22937
};
Word16 tmp;
Word16 qua_ener_MR122;
Word16 qua_ener;
/* calculate median of last five gain values */
tmp = gmed_n(st->gbuf, 5);
/* new gain = minimum(median, past_gain) * cdown[state] */
if (sub(tmp, st->past_gain_code, pOverflow) > 0)
{
tmp = st->past_gain_code;
}
tmp = mult(tmp, cdown[state], pOverflow);
*gain_code = tmp;
/* update table of past quantized energies with average of
* current values
*/
gc_pred_average_limited(pred_state, &qua_ener_MR122, &qua_ener, pOverflow);
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
}
/*
********************************************************************************
* PRIVATE PROGRAM CODE
********************************************************************************
*/
void MR475_quant_store_results(
gc_predState *pred_st, /* i/o: gain predictor state struct */
const Word16 *p, /* i : pointer to selected quantizer table entry */
Word16 gcode0, /* i : predicted CB gain, Q(14 - exp_gcode0) */
Word16 exp_gcode0, /* i : exponent of predicted CB gain, Q0 */
Word16 *gain_pit, /* o : Pitch gain, Q14 */
Word16 *gain_cod /* o : Code gain, Q1 */
)
{
Word16 g_code, exp, frac, tmp;
Word32 L_tmp;
Word16 qua_ener_MR122; /* o : quantized energy error, MR122 version Q10 */
Word16 qua_ener; /* o : quantized energy error, Q10 */
/* Read the quantized gains */
*gain_pit = *p++;
g_code = *p++;
/*------------------------------------------------------------------*
* calculate final fixed codebook gain: *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
* *
* gc = gc0 * g *
*------------------------------------------------------------------*/
L_tmp = L_mult(g_code, gcode0);
L_tmp = L_shr(L_tmp, sub(10, exp_gcode0));
*gain_cod = extract_h(L_tmp);
/*------------------------------------------------------------------*
* calculate predictor update values and update gain predictor: *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
* *
* qua_ener = log2(g) *
* qua_ener_MR122 = 20*log10(g) *
*------------------------------------------------------------------*/
Log2 (L_deposit_l (g_code), &exp, &frac); /* Log2(x Q12) = log2(x) + 12 */
exp = sub(exp, 12);
tmp = shr_r (frac, 5);
qua_ener_MR122 = add (tmp, shl (exp, 10));
L_tmp = Mpy_32_16(exp, frac, 24660); /* 24660 Q12 ~= 6.0206 = 20*log10(2) */
qua_ener = round (L_shl (L_tmp, 13)); /* Q12 * Q0 = Q13 -> Q10 */
gc_pred_update(pred_st, qua_ener_MR122, qua_ener);
}
/*************************************************************************
*
* FUNCTION: Dec_gain()
*
* PURPOSE: Decode the pitch and codebook gains
*
************************************************************************/
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. */
)
{
const Word16 *p;
Word16 frac, gcode0, exp, qua_ener, qua_ener_MR122;
Word16 g_code;
Word32 L_tmp;
/* Read the quantized gains (table depends on mode) */
index = shl (index, 2);
test(); test(); test();
if ( sub (mode, MR102) == 0
|| sub (mode, MR74) == 0
|| sub (mode, MR67) == 0)
{
p = &table_gain_highrates[index]; move16 ();
*gain_pit = *p++; move16 ();
g_code = *p++; move16 ();
qua_ener_MR122 = *p++; move16 ();
qua_ener = *p; move16 ();
}
else
{
test();
if (sub (mode, MR475) == 0)
{
index = add (index, shl(sub(1, evenSubfr), 1));
p = &table_gain_MR475[index]; move16 ();
*gain_pit = *p++; move16 ();
g_code = *p++; move16 ();
/*---------------------------------------------------------*
* 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 */
Log2 (L_deposit_l (g_code), &exp, &frac);
exp = sub(exp, 12);
qua_ener_MR122 = add (shr_r (frac, 5), shl (exp, 10));
/* 24660 Q12 ~= 6.0206 = 20*log10(2) */
L_tmp = Mpy_32_16(exp, frac, 24660);
qua_ener = round (L_shl (L_tmp, 13)); /* Q12 * Q0 = Q13 -> Q10 */
}
else
{
p = &table_gain_lowrates[index]; move16 ();
*gain_pit = *p++; move16 ();
g_code = *p++; move16 ();
qua_ener_MR122 = *p++; move16 ();
qua_ener = *p; move16 ();
}
}
/*-------------------------------------------------------------------*
* 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);
gcode0 = extract_l(Pow2(14, frac));
/*------------------------------------------------------------------*
* 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);
L_tmp = L_shr(L_tmp, sub(10, exp));
*gain_cod = extract_h(L_tmp);
/* update table of past quantized energies */
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
return;
}
//=============================================================================
//函数名称:Dec_gain
//函数功能:解码的音调和码书增益
//=============================================================================
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) */
//阅读量化收益（表取决于模式）
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) *
*---------------------------------------------------------*/
//计算预测更新值（不存储在4.75量化表，以节省空间）
/* 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 */
//过去的量化能量表更新
gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
return;
}
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;
}
