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27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31
32 #include "main_FLP.h"
33 #include "tuning_parameters.h"
34
silk_find_LTP_FLP(silk_float b[MAX_NB_SUBFR * LTP_ORDER],silk_float WLTP[MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER],silk_float * LTPredCodGain,const silk_float r_lpc[],const opus_int lag[MAX_NB_SUBFR],const silk_float Wght[MAX_NB_SUBFR],const opus_int subfr_length,const opus_int nb_subfr,const opus_int mem_offset)35 void silk_find_LTP_FLP(
36 silk_float b[ MAX_NB_SUBFR * LTP_ORDER ], /* O LTP coefs */
37 silk_float WLTP[ MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER ], /* O Weight for LTP quantization */
38 silk_float *LTPredCodGain, /* O LTP coding gain */
39 const silk_float r_lpc[], /* I LPC residual */
40 const opus_int lag[ MAX_NB_SUBFR ], /* I LTP lags */
41 const silk_float Wght[ MAX_NB_SUBFR ], /* I Weights */
42 const opus_int subfr_length, /* I Subframe length */
43 const opus_int nb_subfr, /* I number of subframes */
44 const opus_int mem_offset /* I Number of samples in LTP memory */
45 )
46 {
47 opus_int i, k;
48 silk_float *b_ptr, temp, *WLTP_ptr;
49 silk_float LPC_res_nrg, LPC_LTP_res_nrg;
50 silk_float d[ MAX_NB_SUBFR ], m, g, delta_b[ LTP_ORDER ];
51 silk_float w[ MAX_NB_SUBFR ], nrg[ MAX_NB_SUBFR ], regu;
52 silk_float Rr[ LTP_ORDER ], rr[ MAX_NB_SUBFR ];
53 const silk_float *r_ptr, *lag_ptr;
54
55 b_ptr = b;
56 WLTP_ptr = WLTP;
57 r_ptr = &r_lpc[ mem_offset ];
58 for( k = 0; k < nb_subfr; k++ ) {
59 lag_ptr = r_ptr - ( lag[ k ] + LTP_ORDER / 2 );
60
61 silk_corrMatrix_FLP( lag_ptr, subfr_length, LTP_ORDER, WLTP_ptr );
62 silk_corrVector_FLP( lag_ptr, r_ptr, subfr_length, LTP_ORDER, Rr );
63
64 rr[ k ] = ( silk_float )silk_energy_FLP( r_ptr, subfr_length );
65 regu = 1.0f + rr[ k ] +
66 matrix_ptr( WLTP_ptr, 0, 0, LTP_ORDER ) +
67 matrix_ptr( WLTP_ptr, LTP_ORDER-1, LTP_ORDER-1, LTP_ORDER );
68 regu *= LTP_DAMPING / 3;
69 silk_regularize_correlations_FLP( WLTP_ptr, &rr[ k ], regu, LTP_ORDER );
70 silk_solve_LDL_FLP( WLTP_ptr, LTP_ORDER, Rr, b_ptr );
71
72 /* Calculate residual energy */
73 nrg[ k ] = silk_residual_energy_covar_FLP( b_ptr, WLTP_ptr, Rr, rr[ k ], LTP_ORDER );
74
75 temp = Wght[ k ] / ( nrg[ k ] * Wght[ k ] + 0.01f * subfr_length );
76 silk_scale_vector_FLP( WLTP_ptr, temp, LTP_ORDER * LTP_ORDER );
77 w[ k ] = matrix_ptr( WLTP_ptr, LTP_ORDER / 2, LTP_ORDER / 2, LTP_ORDER );
78
79 r_ptr += subfr_length;
80 b_ptr += LTP_ORDER;
81 WLTP_ptr += LTP_ORDER * LTP_ORDER;
82 }
83
84 /* Compute LTP coding gain */
85 if( LTPredCodGain != NULL ) {
86 LPC_LTP_res_nrg = 1e-6f;
87 LPC_res_nrg = 0.0f;
88 for( k = 0; k < nb_subfr; k++ ) {
89 LPC_res_nrg += rr[ k ] * Wght[ k ];
90 LPC_LTP_res_nrg += nrg[ k ] * Wght[ k ];
91 }
92
93 silk_assert( LPC_LTP_res_nrg > 0 );
94 *LTPredCodGain = 3.0f * silk_log2( LPC_res_nrg / LPC_LTP_res_nrg );
95 }
96
97 /* Smoothing */
98 /* d = sum( B, 1 ); */
99 b_ptr = b;
100 for( k = 0; k < nb_subfr; k++ ) {
101 d[ k ] = 0;
102 for( i = 0; i < LTP_ORDER; i++ ) {
103 d[ k ] += b_ptr[ i ];
104 }
105 b_ptr += LTP_ORDER;
106 }
107 /* m = ( w * d' ) / ( sum( w ) + 1e-3 ); */
108 temp = 1e-3f;
109 for( k = 0; k < nb_subfr; k++ ) {
110 temp += w[ k ];
111 }
112 m = 0;
113 for( k = 0; k < nb_subfr; k++ ) {
114 m += d[ k ] * w[ k ];
115 }
116 m = m / temp;
117
118 b_ptr = b;
119 for( k = 0; k < nb_subfr; k++ ) {
120 g = LTP_SMOOTHING / ( LTP_SMOOTHING + w[ k ] ) * ( m - d[ k ] );
121 temp = 0;
122 for( i = 0; i < LTP_ORDER; i++ ) {
123 delta_b[ i ] = silk_max_float( b_ptr[ i ], 0.1f );
124 temp += delta_b[ i ];
125 }
126 temp = g / temp;
127 for( i = 0; i < LTP_ORDER; i++ ) {
128 b_ptr[ i ] = b_ptr[ i ] + delta_b[ i ] * temp;
129 }
130 b_ptr += LTP_ORDER;
131 }
132 }
133