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27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "main_FLP.h"
33
34#define MAX_ITERATIONS_RESIDUAL_NRG         10
35#define REGULARIZATION_FACTOR               1e-8f
36
37/* Residual energy: nrg = wxx - 2 * wXx * c + c' * wXX * c */
38silk_float silk_residual_energy_covar_FLP(                              /* O    Weighted residual energy                    */
39    const silk_float                *c,                                 /* I    Filter coefficients                         */
40    silk_float                      *wXX,                               /* I/O  Weighted correlation matrix, reg. out       */
41    const silk_float                *wXx,                               /* I    Weighted correlation vector                 */
42    const silk_float                wxx,                                /* I    Weighted correlation value                  */
43    const opus_int                  D                                   /* I    Dimension                                   */
44)
45{
46    opus_int   i, j, k;
47    silk_float tmp, nrg = 0.0f, regularization;
48
49    /* Safety checks */
50    silk_assert( D >= 0 );
51
52    regularization = REGULARIZATION_FACTOR * ( wXX[ 0 ] + wXX[ D * D - 1 ] );
53    for( k = 0; k < MAX_ITERATIONS_RESIDUAL_NRG; k++ ) {
54        nrg = wxx;
55
56        tmp = 0.0f;
57        for( i = 0; i < D; i++ ) {
58            tmp += wXx[ i ] * c[ i ];
59        }
60        nrg -= 2.0f * tmp;
61
62        /* compute c' * wXX * c, assuming wXX is symmetric */
63        for( i = 0; i < D; i++ ) {
64            tmp = 0.0f;
65            for( j = i + 1; j < D; j++ ) {
66                tmp += matrix_c_ptr( wXX, i, j, D ) * c[ j ];
67            }
68            nrg += c[ i ] * ( 2.0f * tmp + matrix_c_ptr( wXX, i, i, D ) * c[ i ] );
69        }
70        if( nrg > 0 ) {
71            break;
72        } else {
73            /* Add white noise */
74            for( i = 0; i < D; i++ ) {
75                matrix_c_ptr( wXX, i, i, D ) +=  regularization;
76            }
77            /* Increase noise for next run */
78            regularization *= 2.0f;
79        }
80    }
81    if( k == MAX_ITERATIONS_RESIDUAL_NRG ) {
82        silk_assert( nrg == 0 );
83        nrg = 1.0f;
84    }
85
86    return nrg;
87}
88
89/* Calculates residual energies of input subframes where all subframes have LPC_order   */
90/* of preceding samples                                                                 */
91void silk_residual_energy_FLP(
92    silk_float                      nrgs[ MAX_NB_SUBFR ],               /* O    Residual energy per subframe                */
93    const silk_float                x[],                                /* I    Input signal                                */
94    silk_float                      a[ 2 ][ MAX_LPC_ORDER ],            /* I    AR coefs for each frame half                */
95    const silk_float                gains[],                            /* I    Quantization gains                          */
96    const opus_int                  subfr_length,                       /* I    Subframe length                             */
97    const opus_int                  nb_subfr,                           /* I    number of subframes                         */
98    const opus_int                  LPC_order                           /* I    LPC order                                   */
99)
100{
101    opus_int     shift;
102    silk_float   *LPC_res_ptr, LPC_res[ ( MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ) / 2 ];
103
104    LPC_res_ptr = LPC_res + LPC_order;
105    shift = LPC_order + subfr_length;
106
107    /* Filter input to create the LPC residual for each frame half, and measure subframe energies */
108    silk_LPC_analysis_filter_FLP( LPC_res, a[ 0 ], x + 0 * shift, 2 * shift, LPC_order );
109    nrgs[ 0 ] = ( silk_float )( gains[ 0 ] * gains[ 0 ] * silk_energy_FLP( LPC_res_ptr + 0 * shift, subfr_length ) );
110    nrgs[ 1 ] = ( silk_float )( gains[ 1 ] * gains[ 1 ] * silk_energy_FLP( LPC_res_ptr + 1 * shift, subfr_length ) );
111
112    if( nb_subfr == MAX_NB_SUBFR ) {
113        silk_LPC_analysis_filter_FLP( LPC_res, a[ 1 ], x + 2 * shift, 2 * shift, LPC_order );
114        nrgs[ 2 ] = ( silk_float )( gains[ 2 ] * gains[ 2 ] * silk_energy_FLP( LPC_res_ptr + 0 * shift, subfr_length ) );
115        nrgs[ 3 ] = ( silk_float )( gains[ 3 ] * gains[ 3 ] * silk_energy_FLP( LPC_res_ptr + 1 * shift, subfr_length ) );
116    }
117}
118