demboyz/external/SILK_SDK_SRC_FLP_v1.0.9/src/SKP_Silk_prefilter_FLP.c

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/***********************************************************************
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modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/
#include "SKP_Silk_main_FLP.h"
#include "SKP_Silk_tuning_parameters.h"
/*
* SKP_Silk_prefilter. Prefilter for finding Quantizer input signal
*/
SKP_INLINE void SKP_Silk_prefilt_FLP(
SKP_Silk_prefilter_state_FLP *P,/* I/O state */
SKP_float st_res[], /* I */
SKP_float xw[], /* O */
SKP_float *HarmShapeFIR, /* I */
SKP_float Tilt, /* I */
SKP_float LF_MA_shp, /* I */
SKP_float LF_AR_shp, /* I */
SKP_int lag, /* I */
SKP_int length /* I */
);
void SKP_Silk_warped_LPC_analysis_filter_FLP(
SKP_float state[], /* I/O State [order + 1] */
SKP_float res[], /* O Residual signal [length] */
const SKP_float coef[], /* I Coefficients [order] */
const SKP_float input[], /* I Input signal [length] */
const SKP_float lambda, /* I Warping factor */
const SKP_int length, /* I Length of input signal */
const SKP_int order /* I Filter order (even) */
)
{
SKP_int n, i;
SKP_float acc, tmp1, tmp2;
/* Order must be even */
SKP_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;
}
}
/*
* SKP_Silk_prefilter. Main prefilter function
*/
void SKP_Silk_prefilter_FLP(
SKP_Silk_encoder_state_FLP *psEnc, /* I/O Encoder state FLP */
const SKP_Silk_encoder_control_FLP *psEncCtrl, /* I Encoder control FLP */
SKP_float xw[], /* O Weighted signal */
const SKP_float x[] /* I Speech signal */
)
{
SKP_Silk_prefilter_state_FLP *P = &psEnc->sPrefilt;
SKP_int j, k, lag;
SKP_float HarmShapeGain, Tilt, LF_MA_shp, LF_AR_shp;
SKP_float B[ 2 ];
const SKP_float *AR1_shp;
const SKP_float *px;
SKP_float *pxw;
SKP_float HarmShapeFIR[ 3 ];
SKP_float st_res[ MAX_FRAME_LENGTH / NB_SUBFR + MAX_SHAPE_LPC_ORDER ];
/* Set up pointers */
px = x;
pxw = xw;
lag = P->lagPrev;
for( k = 0; k < NB_SUBFR; k++ ) {
/* Update Variables that change per sub frame */
if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
lag = psEncCtrl->sCmn.pitchL[ k ];
}
/* Noise shape parameters */
HarmShapeGain = psEncCtrl->HarmShapeGain[ k ] * ( 1.0f - psEncCtrl->HarmBoost[ k ] );
HarmShapeFIR[ 0 ] = SKP_Silk_HarmShapeFIR_FLP[ 0 ] * HarmShapeGain;
HarmShapeFIR[ 1 ] = SKP_Silk_HarmShapeFIR_FLP[ 1 ] * HarmShapeGain;
HarmShapeFIR[ 2 ] = SKP_Silk_HarmShapeFIR_FLP[ 2 ] * 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 */
SKP_Silk_warped_LPC_analysis_filter_FLP( P->sAR_shp, st_res, AR1_shp, px,
(SKP_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 ];
SKP_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->sCmn.pitchL[ NB_SUBFR - 1 ];
}
/*
* Prefilter for finding Quantizer input signal
*/
SKP_INLINE void SKP_Silk_prefilt_FLP(
SKP_Silk_prefilter_state_FLP *P,/* I/O state */
SKP_float st_res[], /* I */
SKP_float xw[], /* O */
SKP_float *HarmShapeFIR, /* I */
SKP_float Tilt, /* I */
SKP_float LF_MA_shp, /* I */
SKP_float LF_AR_shp, /* I */
SKP_int lag, /* I */
SKP_int length /* I */
)
{
SKP_int i;
SKP_int idx, LTP_shp_buf_idx;
SKP_float n_Tilt, n_LF, n_LTP;
SKP_float sLF_AR_shp, sLF_MA_shp;
SKP_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 ) {
SKP_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;
}