ref: 07418d9dd8c486c4b3842a4268b272ed6f1b9c54
dir: /silk/float/prefilter_FLP.c/
/***********************************************************************
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***********************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main_FLP.h"
#include "tuning_parameters.h"
/*
* Prefilter for finding Quantizer input signal
*/
static inline void silk_prefilt_FLP(
silk_prefilter_state_FLP *P, /* I/O state */
silk_float st_res[], /* I */
silk_float xw[], /* O */
silk_float *HarmShapeFIR, /* I */
silk_float Tilt, /* I */
silk_float LF_MA_shp, /* I */
silk_float LF_AR_shp, /* I */
opus_int lag, /* I */
opus_int length /* I */
);
static void silk_warped_LPC_analysis_filter_FLP(
silk_float state[], /* I/O State [order + 1] */
silk_float res[], /* O Residual signal [length] */
const silk_float coef[], /* I Coefficients [order] */
const silk_float input[], /* I Input signal [length] */
const silk_float lambda, /* I Warping factor */
const opus_int length, /* I Length of input signal */
const opus_int order /* I Filter order (even) */
)
{
opus_int n, i;
silk_float acc, tmp1, tmp2;
/* Order must be even */
silk_assert( ( order & 1 ) == 0 );
for( n = 0; n < length; n++ ) {
/* Output of lowpass section */
tmp2 = state[ 0 ] + lambda * state[ 1 ];
state[ 0 ] = input[ n ];
/* Output of allpass section */
tmp1 = state[ 1 ] + lambda * ( state[ 2 ] - tmp2 );
state[ 1 ] = tmp2;
acc = coef[ 0 ] * tmp2;
/* Loop over allpass sections */
for( i = 2; i < order; i += 2 ) {
/* Output of allpass section */
tmp2 = state[ i ] + lambda * ( state[ i + 1 ] - tmp1 );
state[ i ] = tmp1;
acc += coef[ i - 1 ] * tmp1;
/* Output of allpass section */
tmp1 = state[ i + 1 ] + lambda * ( state[ i + 2 ] - tmp2 );
state[ i + 1 ] = tmp2;
acc += coef[ i ] * tmp2;
}
state[ order ] = tmp1;
acc += coef[ order - 1 ] * tmp1;
res[ n ] = input[ n ] - acc;
}
}
/*
* silk_prefilter. Main prefilter function
*/
void silk_prefilter_FLP(
silk_encoder_state_FLP *psEnc, /* I/O Encoder state FLP */
const silk_encoder_control_FLP *psEncCtrl, /* I Encoder control FLP */
silk_float xw[], /* O Weighted signal */
const silk_float x[] /* I Speech signal */
)
{
silk_prefilter_state_FLP *P = &psEnc->sPrefilt;
opus_int j, k, lag;
silk_float HarmShapeGain, Tilt, LF_MA_shp, LF_AR_shp;
silk_float B[ 2 ];
const silk_float *AR1_shp;
const silk_float *px;
silk_float *pxw;
silk_float HarmShapeFIR[ 3 ];
silk_float st_res[ MAX_SUB_FRAME_LENGTH + MAX_LPC_ORDER ];
/* Set up pointers */
px = x;
pxw = xw;
lag = P->lagPrev;
for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {
/* Update Variables that change per sub frame */
if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
lag = psEncCtrl->pitchL[ k ];
}
/* Noise shape parameters */
HarmShapeGain = psEncCtrl->HarmShapeGain[ k ] * ( 1.0f - psEncCtrl->HarmBoost[ k ] );
HarmShapeFIR[ 0 ] = 0.25f * HarmShapeGain;
HarmShapeFIR[ 1 ] = 32767.0f / 65536.0f * HarmShapeGain;
HarmShapeFIR[ 2 ] = 0.25f * HarmShapeGain;
Tilt = psEncCtrl->Tilt[ k ];
LF_MA_shp = psEncCtrl->LF_MA_shp[ k ];
LF_AR_shp = psEncCtrl->LF_AR_shp[ k ];
AR1_shp = &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ];
/* Short term FIR filtering */
silk_warped_LPC_analysis_filter_FLP( P->sAR_shp, st_res, AR1_shp, px,
(silk_float)psEnc->sCmn.warping_Q16 / 65536.0f, psEnc->sCmn.subfr_length, psEnc->sCmn.shapingLPCOrder );
/* Reduce (mainly) low frequencies during harmonic emphasis */
B[ 0 ] = psEncCtrl->GainsPre[ k ];
B[ 1 ] = -psEncCtrl->GainsPre[ k ] *
( psEncCtrl->HarmBoost[ k ] * HarmShapeGain + INPUT_TILT + psEncCtrl->coding_quality * HIGH_RATE_INPUT_TILT );
pxw[ 0 ] = B[ 0 ] * st_res[ 0 ] + B[ 1 ] * P->sHarmHP;
for( j = 1; j < psEnc->sCmn.subfr_length; j++ ) {
pxw[ j ] = B[ 0 ] * st_res[ j ] + B[ 1 ] * st_res[ j - 1 ];
}
P->sHarmHP = st_res[ psEnc->sCmn.subfr_length - 1 ];
silk_prefilt_FLP( P, pxw, pxw, HarmShapeFIR, Tilt, LF_MA_shp, LF_AR_shp, lag, psEnc->sCmn.subfr_length );
px += psEnc->sCmn.subfr_length;
pxw += psEnc->sCmn.subfr_length;
}
P->lagPrev = psEncCtrl->pitchL[ psEnc->sCmn.nb_subfr - 1 ];
}
/*
* Prefilter for finding Quantizer input signal
*/
static inline void silk_prefilt_FLP(
silk_prefilter_state_FLP *P, /* I/O state */
silk_float st_res[], /* I */
silk_float xw[], /* O */
silk_float *HarmShapeFIR, /* I */
silk_float Tilt, /* I */
silk_float LF_MA_shp, /* I */
silk_float LF_AR_shp, /* I */
opus_int lag, /* I */
opus_int length /* I */
)
{
opus_int i;
opus_int idx, LTP_shp_buf_idx;
silk_float n_Tilt, n_LF, n_LTP;
silk_float sLF_AR_shp, sLF_MA_shp;
silk_float *LTP_shp_buf;
/* To speed up use temp variables instead of using the struct */
LTP_shp_buf = P->sLTP_shp;
LTP_shp_buf_idx = P->sLTP_shp_buf_idx;
sLF_AR_shp = P->sLF_AR_shp;
sLF_MA_shp = P->sLF_MA_shp;
for( i = 0; i < length; i++ ) {
if( lag > 0 ) {
silk_assert( HARM_SHAPE_FIR_TAPS == 3 );
idx = lag + LTP_shp_buf_idx;
n_LTP = LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 - 1) & LTP_MASK ] * HarmShapeFIR[ 0 ];
n_LTP += LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 ) & LTP_MASK ] * HarmShapeFIR[ 1 ];
n_LTP += LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 + 1) & LTP_MASK ] * HarmShapeFIR[ 2 ];
} else {
n_LTP = 0;
}
n_Tilt = sLF_AR_shp * Tilt;
n_LF = sLF_AR_shp * LF_AR_shp + sLF_MA_shp * LF_MA_shp;
sLF_AR_shp = st_res[ i ] - n_Tilt;
sLF_MA_shp = sLF_AR_shp - n_LF;
LTP_shp_buf_idx = ( LTP_shp_buf_idx - 1 ) & LTP_MASK;
LTP_shp_buf[ LTP_shp_buf_idx ] = sLF_MA_shp;
xw[ i ] = sLF_MA_shp - n_LTP;
}
/* Copy temp variable back to state */
P->sLF_AR_shp = sLF_AR_shp;
P->sLF_MA_shp = sLF_MA_shp;
P->sLTP_shp_buf_idx = LTP_shp_buf_idx;
}