/*************************************************************************
*
* Function: cl_ltp
* Purpose: closed-loop fractional pitch search
*
**************************************************************************
*/
void cl_ltp (
clLtpState *clSt, /* i/o : State struct */
tonStabState *tonSt, /* i/o : State struct */
enum Mode mode, /* i : coder mode */
Word16 frameOffset, /* i : Offset to subframe */
Word16 T_op[], /* i : Open loop pitch lags */
Word16 *h1, /* i : Impulse response vector Q12 */
Word16 *exc, /* i/o : Excitation vector Q0 */
Word16 res2[], /* i/o : Long term prediction residual Q0 */
Word16 xn[], /* i : Target vector for pitch search Q0 */
Word16 lsp_flag, /* i : LSP resonance flag */
Word16 xn2[], /* o : Target vector for codebook search Q0 */
Word16 y1[], /* o : Filtered adaptive excitation Q0 */
Word16 *T0, /* o : Pitch delay (integer part) */
Word16 *T0_frac, /* o : Pitch delay (fractional part) */
Word16 *gain_pit, /* o : Pitch gain Q14 */
Word16 g_coeff[], /* o : Correlations between xn, y1, & y2 */
Word16 **anap, /* o : Analysis parameters */
Word16 *gp_limit /* o : pitch gain limit */
)
{
Word16 i;
Word16 index;
Word32 L_temp; /* temporarily variable */
Word16 resu3; /* flag for upsample resolution */
Word16 gpc_flag;
/*----------------------------------------------------------------------*
* Closed-loop fractional pitch search *
*----------------------------------------------------------------------*/
*T0 = Pitch_fr(&clSt->pitchSt,
mode, T_op, exc, xn, h1,
L_SUBFR, frameOffset,
T0_frac, &resu3, &index);
*(*anap)++ = index;
/*-----------------------------------------------------------------*
* - find unity gain pitch excitation (adapitve codebook entry) *
* with fractional interpolation. *
* - find filtered pitch exc. y1[]=exc[] convolve with h1[]) *
* - compute pitch gain and limit between 0 and 1.2 *
* - update target vector for codebook search *
* - find LTP residual. *
*-----------------------------------------------------------------*/
Pred_lt_3or6(exc, *T0, *T0_frac, L_SUBFR, resu3);
Convolve(exc, h1, y1, L_SUBFR);
/* gain_pit is Q14 for all modes */
*gain_pit = G_pitch(mode, xn, y1, g_coeff, L_SUBFR);
/* check if the pitch gain should be limit due to resonance in LPC filter */
gpc_flag = 0;
*gp_limit = MAX_16;
if (lsp_flag != 0 && *gain_pit > GP_CLIP)
{
gpc_flag = check_gp_clipping(tonSt, *gain_pit);
}
/* special for the MR475, MR515 mode; limit the gain to 0.85 to */
/* cope with bit errors in the decoder in a better way. */
if (mode == MR475 || mode == MR515) {
if (*gain_pit > 13926) {
*gain_pit = 13926; /* 0.85 in Q14 */
}
if (gpc_flag != 0) {
*gp_limit = GP_CLIP;
}
}
else
{
if (gpc_flag != 0)
{
*gp_limit = GP_CLIP;
*gain_pit = GP_CLIP;
}
/* For MR122, gain_pit is quantized here and not in gainQuant */
if ( mode == MR122 )
{
*(*anap)++ = q_gain_pitch(MR122, *gp_limit, gain_pit,
NULL, NULL);
}
}
/* update target vector und evaluate LTP residual */
for (i = 0; i < L_SUBFR; i++) {
L_temp = ((Word32)y1[i] * *gain_pit) >> 14;
xn2[i] = xn[i] - (Word16)L_temp;
L_temp = ((Word32)exc[i] * *gain_pit) >> 14;
res2[i] -= (Word16)L_temp;
}
}
/*************************************************************************
*
* 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, 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)*/
)
{
Word16 frac_en[4];
Word16 exp_en[4];
Word16 ltpg, alpha, gcode0;
Word16 g_pitch_cand[3]; /* pitch gain candidates Q14 */
Word16 g_pitch_cind[3]; /* pitch gain indices Q0 */
Word16 gain_pit_index;
Word16 gain_cod_index;
Word16 exp;
Word16 gain_cod_unq; /* code gain (unq.) Q(10-exp_gcode0) */
/* get list of candidate quantized pitch gain values
* and corresponding quantization indices
*/
gain_pit_index = q_gain_pitch (MR795, gp_limit, gain_pit,
g_pitch_cand, g_pitch_cind);
/* function result */
/*-------------------------------------------------------------------*
* predicted codebook gain *
* ~~~~~~~~~~~~~~~~~~~~~~~ *
* gc0 = 2^exp_gcode0 + 2^frac_gcode0 *
* *
* gcode0 (Q14) = 2^14*2^frac_gcode0 = gc0 * 2^(14-exp_gcode0) *
*-------------------------------------------------------------------*/
gcode0 = extract_l(Pow2(14, frac_gcode0)); /* Q14 */
/* pre-quantization of codebook gain
* (using three pitch gain candidates);
* result: best guess of pitch gain and code gain
*/
MR795_gain_code_quant3(
exp_gcode0, gcode0, g_pitch_cand, g_pitch_cind,
frac_coeff, exp_coeff,
gain_pit, &gain_pit_index, gain_cod, &gain_cod_index,
qua_ener_MR122, qua_ener);
/* calculation of energy coefficients and LTP coding gain */
calc_unfilt_energies(res, exc, code, *gain_pit, L_subfr,
frac_en, exp_en, <pg);
/* run gain adaptor, calculate alpha factor to balance LTP/CB gain
* (this includes the gain adaptor update)
* Note: ltpg = 0 if frac_en[0] == 0, so the update is OK in that case
*/
gain_adapt(adapt_st, ltpg, *gain_cod, &alpha);
/* if this is a very low energy signal (threshold: see
* calc_unfilt_energies) or alpha <= 0 then don't run the modified quantizer
*/
if (frac_en[0] != 0 && alpha > 0)
{
/* innovation energy <cod cod> was already computed in gc_pred() */
/* (this overwrites the LtpResEn which is no longer needed) */
frac_en[3] = frac_code_en;
exp_en[3] = exp_code_en;
/* store optimum codebook gain in Q(10-exp_gcode0) */
exp = add (sub (cod_gain_exp, exp_gcode0), 10);
gain_cod_unq = shl (cod_gain_frac, exp);
/* run quantization with modified criterion */
gain_cod_index = MR795_gain_code_quant_mod(
*gain_pit, exp_gcode0, gcode0,
frac_en, exp_en, alpha, gain_cod_unq,
gain_cod, qua_ener_MR122, qua_ener); /* function result */
}
*(*anap)++ = gain_pit_index;
*(*anap)++ = gain_cod_index;
}
