ref: 9edde42690a11afea6681275411d2c5f16484ea4
dir: /silk/float/SKP_Silk_residual_energy_FLP.c/
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#include "SKP_Silk_main_FLP.h"
#define MAX_ITERATIONS_RESIDUAL_NRG 10
#define REGULARIZATION_FACTOR 1e-8f
/* Residual energy: nrg = wxx - 2 * wXx * c + c' * wXX * c */
SKP_float SKP_Silk_residual_energy_covar_FLP( /* O Weighted residual energy */
const SKP_float *c, /* I Filter coefficients */
SKP_float *wXX, /* I/O Weighted correlation matrix, reg. out */
const SKP_float *wXx, /* I Weighted correlation vector */
const SKP_float wxx, /* I Weighted correlation value */
const SKP_int D /* I Dimension */
)
{
SKP_int i, j, k;
SKP_float tmp, nrg, regularization;
/* Safety checks */
SKP_assert( D >= 0 );
regularization = REGULARIZATION_FACTOR * ( wXX[ 0 ] + wXX[ D * D - 1 ] );
for( k = 0; k < MAX_ITERATIONS_RESIDUAL_NRG; k++ ) {
nrg = wxx;
tmp = 0.0f;
for( i = 0; i < D; i++ ) {
tmp += wXx[ i ] * c[ i ];
}
nrg -= 2.0f * tmp;
/* compute c' * wXX * c, assuming wXX is symmetric */
for( i = 0; i < D; i++ ) {
tmp = 0.0f;
for( j = i + 1; j < D; j++ ) {
tmp += matrix_c_ptr( wXX, i, j, D ) * c[ j ];
}
nrg += c[ i ] * ( 2.0f * tmp + matrix_c_ptr( wXX, i, i, D ) * c[ i ] );
}
if( nrg > 0 ) {
break;
} else {
/* Add white noise */
for( i = 0; i < D; i++ ) {
matrix_c_ptr( wXX, i, i, D ) += regularization;
}
/* Increase noise for next run */
regularization *= 2.0f;
}
}
if( k == MAX_ITERATIONS_RESIDUAL_NRG ) {
SKP_assert( nrg == 0 );
nrg = 1.0f;
}
return nrg;
}
/* Calculates residual energies of input subframes where all subframes have LPC_order */
/* of preceeding samples */
void SKP_Silk_residual_energy_FLP(
SKP_float nrgs[ MAX_NB_SUBFR ], /* O Residual energy per subframe */
const SKP_float x[], /* I Input signal */
const SKP_float a[ 2 ][ MAX_LPC_ORDER ], /* I AR coefs for each frame half */
const SKP_float gains[], /* I Quantization gains */
const SKP_int subfr_length, /* I Subframe length */
const SKP_int nb_subfr, /* I number of subframes */
const SKP_int LPC_order /* I LPC order */
)
{
SKP_int shift;
SKP_float *LPC_res_ptr, LPC_res[ ( MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ) / 2 ];
LPC_res_ptr = LPC_res + LPC_order;
shift = LPC_order + subfr_length;
/* Filter input to create the LPC residual for each frame half, and measure subframe energies */
SKP_Silk_LPC_analysis_filter_FLP( LPC_res, a[ 0 ], x + 0 * shift, 2 * shift, LPC_order );
nrgs[ 0 ] = ( SKP_float )( gains[ 0 ] * gains[ 0 ] * SKP_Silk_energy_FLP( LPC_res_ptr + 0 * shift, subfr_length ) );
nrgs[ 1 ] = ( SKP_float )( gains[ 1 ] * gains[ 1 ] * SKP_Silk_energy_FLP( LPC_res_ptr + 1 * shift, subfr_length ) );
if( nb_subfr == MAX_NB_SUBFR ) {
SKP_Silk_LPC_analysis_filter_FLP( LPC_res, a[ 1 ], x + 2 * shift, 2 * shift, LPC_order );
nrgs[ 2 ] = ( SKP_float )( gains[ 2 ] * gains[ 2 ] * SKP_Silk_energy_FLP( LPC_res_ptr + 0 * shift, subfr_length ) );
nrgs[ 3 ] = ( SKP_float )( gains[ 3 ] * gains[ 3 ] * SKP_Silk_energy_FLP( LPC_res_ptr + 1 * shift, subfr_length ) );
}
}