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4 modification, are permitted provided that the following conditions
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15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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26 ***********************************************************************/
27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31
32 #include "main.h"
33 #include "stack_alloc.h"
34
35 /* Generates excitation for CNG LPC synthesis */
silk_CNG_exc(opus_int32 residual_Q10[],opus_int32 exc_buf_Q14[],opus_int32 Gain_Q16,opus_int length,opus_int32 * rand_seed)36 static OPUS_INLINE void silk_CNG_exc(
37 opus_int32 residual_Q10[], /* O CNG residual signal Q10 */
38 opus_int32 exc_buf_Q14[], /* I Random samples buffer Q10 */
39 opus_int32 Gain_Q16, /* I Gain to apply */
40 opus_int length, /* I Length */
41 opus_int32 *rand_seed /* I/O Seed to random index generator */
42 )
43 {
44 opus_int32 seed;
45 opus_int i, idx, exc_mask;
46
47 exc_mask = CNG_BUF_MASK_MAX;
48 while( exc_mask > length ) {
49 exc_mask = silk_RSHIFT( exc_mask, 1 );
50 }
51
52 seed = *rand_seed;
53 for( i = 0; i < length; i++ ) {
54 seed = silk_RAND( seed );
55 idx = (opus_int)( silk_RSHIFT( seed, 24 ) & exc_mask );
56 silk_assert( idx >= 0 );
57 silk_assert( idx <= CNG_BUF_MASK_MAX );
58 residual_Q10[ i ] = (opus_int16)silk_SAT16( silk_SMULWW( exc_buf_Q14[ idx ], Gain_Q16 >> 4 ) );
59 }
60 *rand_seed = seed;
61 }
62
silk_CNG_Reset(silk_decoder_state * psDec)63 void silk_CNG_Reset(
64 silk_decoder_state *psDec /* I/O Decoder state */
65 )
66 {
67 opus_int i, NLSF_step_Q15, NLSF_acc_Q15;
68
69 NLSF_step_Q15 = silk_DIV32_16( silk_int16_MAX, psDec->LPC_order + 1 );
70 NLSF_acc_Q15 = 0;
71 for( i = 0; i < psDec->LPC_order; i++ ) {
72 NLSF_acc_Q15 += NLSF_step_Q15;
73 psDec->sCNG.CNG_smth_NLSF_Q15[ i ] = NLSF_acc_Q15;
74 }
75 psDec->sCNG.CNG_smth_Gain_Q16 = 0;
76 psDec->sCNG.rand_seed = 3176576;
77 }
78
79 /* Updates CNG estimate, and applies the CNG when packet was lost */
silk_CNG(silk_decoder_state * psDec,silk_decoder_control * psDecCtrl,opus_int16 frame[],opus_int length)80 void silk_CNG(
81 silk_decoder_state *psDec, /* I/O Decoder state */
82 silk_decoder_control *psDecCtrl, /* I/O Decoder control */
83 opus_int16 frame[], /* I/O Signal */
84 opus_int length /* I Length of residual */
85 )
86 {
87 opus_int i, subfr;
88 opus_int32 sum_Q6, max_Gain_Q16;
89 opus_int16 A_Q12[ MAX_LPC_ORDER ];
90 silk_CNG_struct *psCNG = &psDec->sCNG;
91 SAVE_STACK;
92
93 if( psDec->fs_kHz != psCNG->fs_kHz ) {
94 /* Reset state */
95 silk_CNG_Reset( psDec );
96
97 psCNG->fs_kHz = psDec->fs_kHz;
98 }
99 if( psDec->lossCnt == 0 && psDec->prevSignalType == TYPE_NO_VOICE_ACTIVITY ) {
100 /* Update CNG parameters */
101
102 /* Smoothing of LSF's */
103 for( i = 0; i < psDec->LPC_order; i++ ) {
104 psCNG->CNG_smth_NLSF_Q15[ i ] += silk_SMULWB( (opus_int32)psDec->prevNLSF_Q15[ i ] - (opus_int32)psCNG->CNG_smth_NLSF_Q15[ i ], CNG_NLSF_SMTH_Q16 );
105 }
106 /* Find the subframe with the highest gain */
107 max_Gain_Q16 = 0;
108 subfr = 0;
109 for( i = 0; i < psDec->nb_subfr; i++ ) {
110 if( psDecCtrl->Gains_Q16[ i ] > max_Gain_Q16 ) {
111 max_Gain_Q16 = psDecCtrl->Gains_Q16[ i ];
112 subfr = i;
113 }
114 }
115 /* Update CNG excitation buffer with excitation from this subframe */
116 silk_memmove( &psCNG->CNG_exc_buf_Q14[ psDec->subfr_length ], psCNG->CNG_exc_buf_Q14, ( psDec->nb_subfr - 1 ) * psDec->subfr_length * sizeof( opus_int32 ) );
117 silk_memcpy( psCNG->CNG_exc_buf_Q14, &psDec->exc_Q14[ subfr * psDec->subfr_length ], psDec->subfr_length * sizeof( opus_int32 ) );
118
119 /* Smooth gains */
120 for( i = 0; i < psDec->nb_subfr; i++ ) {
121 psCNG->CNG_smth_Gain_Q16 += silk_SMULWB( psDecCtrl->Gains_Q16[ i ] - psCNG->CNG_smth_Gain_Q16, CNG_GAIN_SMTH_Q16 );
122 }
123 }
124
125 /* Add CNG when packet is lost or during DTX */
126 if( psDec->lossCnt ) {
127 VARDECL( opus_int32, CNG_sig_Q10 );
128
129 ALLOC( CNG_sig_Q10, length + MAX_LPC_ORDER, opus_int32 );
130
131 /* Generate CNG excitation */
132 silk_CNG_exc( CNG_sig_Q10 + MAX_LPC_ORDER, psCNG->CNG_exc_buf_Q14, psCNG->CNG_smth_Gain_Q16, length, &psCNG->rand_seed );
133
134 /* Convert CNG NLSF to filter representation */
135 silk_NLSF2A( A_Q12, psCNG->CNG_smth_NLSF_Q15, psDec->LPC_order );
136
137 /* Generate CNG signal, by synthesis filtering */
138 silk_memcpy( CNG_sig_Q10, psCNG->CNG_synth_state, MAX_LPC_ORDER * sizeof( opus_int32 ) );
139 for( i = 0; i < length; i++ ) {
140 silk_assert( psDec->LPC_order == 10 || psDec->LPC_order == 16 );
141 /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
142 sum_Q6 = silk_RSHIFT( psDec->LPC_order, 1 );
143 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 1 ], A_Q12[ 0 ] );
144 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 2 ], A_Q12[ 1 ] );
145 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 3 ], A_Q12[ 2 ] );
146 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 4 ], A_Q12[ 3 ] );
147 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 5 ], A_Q12[ 4 ] );
148 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 6 ], A_Q12[ 5 ] );
149 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 7 ], A_Q12[ 6 ] );
150 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 8 ], A_Q12[ 7 ] );
151 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 9 ], A_Q12[ 8 ] );
152 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
153 if( psDec->LPC_order == 16 ) {
154 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 11 ], A_Q12[ 10 ] );
155 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 12 ], A_Q12[ 11 ] );
156 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 13 ], A_Q12[ 12 ] );
157 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 14 ], A_Q12[ 13 ] );
158 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 15 ], A_Q12[ 14 ] );
159 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 16 ], A_Q12[ 15 ] );
160 }
161
162 /* Update states */
163 CNG_sig_Q10[ MAX_LPC_ORDER + i ] = silk_ADD_LSHIFT( CNG_sig_Q10[ MAX_LPC_ORDER + i ], sum_Q6, 4 );
164
165 frame[ i ] = silk_ADD_SAT16( frame[ i ], silk_RSHIFT_ROUND( sum_Q6, 6 ) );
166 }
167 silk_memcpy( psCNG->CNG_synth_state, &CNG_sig_Q10[ length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
168 } else {
169 silk_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order * sizeof( opus_int32 ) );
170 }
171 RESTORE_STACK;
172 }
173