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1 /***********************************************************************
2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3 Redistribution and use in source and binary forms, with or without
4 modification, are permitted provided that the following conditions
5 are met:
6 - Redistributions of source code must retain the above copyright notice,
7 this list of conditions and the following disclaimer.
8 - Redistributions in binary form must reproduce the above copyright
9 notice, this list of conditions and the following disclaimer in the
10 documentation and/or other materials provided with the distribution.
11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
12 names of specific contributors, may be used to endorse or promote
13 products derived from this software without specific prior written
14 permission.
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
17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 POSSIBILITY OF SUCH DAMAGE.
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 /**********************************************************/
36 /* Core decoder. Performs inverse NSQ operation LTP + LPC */
37 /**********************************************************/
silk_decode_core(silk_decoder_state * psDec,silk_decoder_control * psDecCtrl,opus_int16 xq[],const opus_int16 pulses[MAX_FRAME_LENGTH],int arch)38 void silk_decode_core(
39     silk_decoder_state          *psDec,                         /* I/O  Decoder state                               */
40     silk_decoder_control        *psDecCtrl,                     /* I    Decoder control                             */
41     opus_int16                  xq[],                           /* O    Decoded speech                              */
42     const opus_int16            pulses[ MAX_FRAME_LENGTH ],     /* I    Pulse signal                                */
43     int                         arch                            /* I    Run-time architecture                       */
44 )
45 {
46     opus_int   i, k, lag = 0, start_idx, sLTP_buf_idx, NLSF_interpolation_flag, signalType;
47     opus_int16 *A_Q12, *B_Q14, *pxq, A_Q12_tmp[ MAX_LPC_ORDER ];
48     VARDECL( opus_int16, sLTP );
49     VARDECL( opus_int32, sLTP_Q15 );
50     opus_int32 LTP_pred_Q13, LPC_pred_Q10, Gain_Q10, inv_gain_Q31, gain_adj_Q16, rand_seed, offset_Q10;
51     opus_int32 *pred_lag_ptr, *pexc_Q14, *pres_Q14;
52     VARDECL( opus_int32, res_Q14 );
53     VARDECL( opus_int32, sLPC_Q14 );
54     SAVE_STACK;
55 
56     silk_assert( psDec->prev_gain_Q16 != 0 );
57 
58     ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
59     ALLOC( sLTP_Q15, psDec->ltp_mem_length + psDec->frame_length, opus_int32 );
60     ALLOC( res_Q14, psDec->subfr_length, opus_int32 );
61     ALLOC( sLPC_Q14, psDec->subfr_length + MAX_LPC_ORDER, opus_int32 );
62 
63     offset_Q10 = silk_Quantization_Offsets_Q10[ psDec->indices.signalType >> 1 ][ psDec->indices.quantOffsetType ];
64 
65     if( psDec->indices.NLSFInterpCoef_Q2 < 1 << 2 ) {
66         NLSF_interpolation_flag = 1;
67     } else {
68         NLSF_interpolation_flag = 0;
69     }
70 
71     /* Decode excitation */
72     rand_seed = psDec->indices.Seed;
73     for( i = 0; i < psDec->frame_length; i++ ) {
74         rand_seed = silk_RAND( rand_seed );
75         psDec->exc_Q14[ i ] = silk_LSHIFT( (opus_int32)pulses[ i ], 14 );
76         if( psDec->exc_Q14[ i ] > 0 ) {
77             psDec->exc_Q14[ i ] -= QUANT_LEVEL_ADJUST_Q10 << 4;
78         } else
79         if( psDec->exc_Q14[ i ] < 0 ) {
80             psDec->exc_Q14[ i ] += QUANT_LEVEL_ADJUST_Q10 << 4;
81         }
82         psDec->exc_Q14[ i ] += offset_Q10 << 4;
83         if( rand_seed < 0 ) {
84            psDec->exc_Q14[ i ] = -psDec->exc_Q14[ i ];
85         }
86 
87         rand_seed = silk_ADD32_ovflw( rand_seed, pulses[ i ] );
88     }
89 
90     /* Copy LPC state */
91     silk_memcpy( sLPC_Q14, psDec->sLPC_Q14_buf, MAX_LPC_ORDER * sizeof( opus_int32 ) );
92 
93     pexc_Q14 = psDec->exc_Q14;
94     pxq      = xq;
95     sLTP_buf_idx = psDec->ltp_mem_length;
96     /* Loop over subframes */
97     for( k = 0; k < psDec->nb_subfr; k++ ) {
98         pres_Q14 = res_Q14;
99         A_Q12 = psDecCtrl->PredCoef_Q12[ k >> 1 ];
100 
101         /* Preload LPC coeficients to array on stack. Gives small performance gain */
102         silk_memcpy( A_Q12_tmp, A_Q12, psDec->LPC_order * sizeof( opus_int16 ) );
103         B_Q14        = &psDecCtrl->LTPCoef_Q14[ k * LTP_ORDER ];
104         signalType   = psDec->indices.signalType;
105 
106         Gain_Q10     = silk_RSHIFT( psDecCtrl->Gains_Q16[ k ], 6 );
107         inv_gain_Q31 = silk_INVERSE32_varQ( psDecCtrl->Gains_Q16[ k ], 47 );
108 
109         /* Calculate gain adjustment factor */
110         if( psDecCtrl->Gains_Q16[ k ] != psDec->prev_gain_Q16 ) {
111             gain_adj_Q16 =  silk_DIV32_varQ( psDec->prev_gain_Q16, psDecCtrl->Gains_Q16[ k ], 16 );
112 
113             /* Scale short term state */
114             for( i = 0; i < MAX_LPC_ORDER; i++ ) {
115                 sLPC_Q14[ i ] = silk_SMULWW( gain_adj_Q16, sLPC_Q14[ i ] );
116             }
117         } else {
118             gain_adj_Q16 = (opus_int32)1 << 16;
119         }
120 
121         /* Save inv_gain */
122         silk_assert( inv_gain_Q31 != 0 );
123         psDec->prev_gain_Q16 = psDecCtrl->Gains_Q16[ k ];
124 
125         /* Avoid abrupt transition from voiced PLC to unvoiced normal decoding */
126         if( psDec->lossCnt && psDec->prevSignalType == TYPE_VOICED &&
127             psDec->indices.signalType != TYPE_VOICED && k < MAX_NB_SUBFR/2 ) {
128 
129             silk_memset( B_Q14, 0, LTP_ORDER * sizeof( opus_int16 ) );
130             B_Q14[ LTP_ORDER/2 ] = SILK_FIX_CONST( 0.25, 14 );
131 
132             signalType = TYPE_VOICED;
133             psDecCtrl->pitchL[ k ] = psDec->lagPrev;
134         }
135 
136         if( signalType == TYPE_VOICED ) {
137             /* Voiced */
138             lag = psDecCtrl->pitchL[ k ];
139 
140             /* Re-whitening */
141             if( k == 0 || ( k == 2 && NLSF_interpolation_flag ) ) {
142                 /* Rewhiten with new A coefs */
143                 start_idx = psDec->ltp_mem_length - lag - psDec->LPC_order - LTP_ORDER / 2;
144                 silk_assert( start_idx > 0 );
145 
146                 if( k == 2 ) {
147                     silk_memcpy( &psDec->outBuf[ psDec->ltp_mem_length ], xq, 2 * psDec->subfr_length * sizeof( opus_int16 ) );
148                 }
149 
150                 silk_LPC_analysis_filter( &sLTP[ start_idx ], &psDec->outBuf[ start_idx + k * psDec->subfr_length ],
151                     A_Q12, psDec->ltp_mem_length - start_idx, psDec->LPC_order, arch );
152 
153                 /* After rewhitening the LTP state is unscaled */
154                 if( k == 0 ) {
155                     /* Do LTP downscaling to reduce inter-packet dependency */
156                     inv_gain_Q31 = silk_LSHIFT( silk_SMULWB( inv_gain_Q31, psDecCtrl->LTP_scale_Q14 ), 2 );
157                 }
158                 for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
159                     sLTP_Q15[ sLTP_buf_idx - i - 1 ] = silk_SMULWB( inv_gain_Q31, sLTP[ psDec->ltp_mem_length - i - 1 ] );
160                 }
161             } else {
162                 /* Update LTP state when Gain changes */
163                 if( gain_adj_Q16 != (opus_int32)1 << 16 ) {
164                     for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
165                         sLTP_Q15[ sLTP_buf_idx - i - 1 ] = silk_SMULWW( gain_adj_Q16, sLTP_Q15[ sLTP_buf_idx - i - 1 ] );
166                     }
167                 }
168             }
169         }
170 
171         /* Long-term prediction */
172         if( signalType == TYPE_VOICED ) {
173             /* Set up pointer */
174             pred_lag_ptr = &sLTP_Q15[ sLTP_buf_idx - lag + LTP_ORDER / 2 ];
175             for( i = 0; i < psDec->subfr_length; i++ ) {
176                 /* Unrolled loop */
177                 /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
178                 LTP_pred_Q13 = 2;
179                 LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[  0 ], B_Q14[ 0 ] );
180                 LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -1 ], B_Q14[ 1 ] );
181                 LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -2 ], B_Q14[ 2 ] );
182                 LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -3 ], B_Q14[ 3 ] );
183                 LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -4 ], B_Q14[ 4 ] );
184                 pred_lag_ptr++;
185 
186                 /* Generate LPC excitation */
187                 pres_Q14[ i ] = silk_ADD_LSHIFT32( pexc_Q14[ i ], LTP_pred_Q13, 1 );
188 
189                 /* Update states */
190                 sLTP_Q15[ sLTP_buf_idx ] = silk_LSHIFT( pres_Q14[ i ], 1 );
191                 sLTP_buf_idx++;
192             }
193         } else {
194             pres_Q14 = pexc_Q14;
195         }
196 
197         for( i = 0; i < psDec->subfr_length; i++ ) {
198             /* Short-term prediction */
199             silk_assert( psDec->LPC_order == 10 || psDec->LPC_order == 16 );
200             /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
201             LPC_pred_Q10 = silk_RSHIFT( psDec->LPC_order, 1 );
202             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  1 ], A_Q12_tmp[ 0 ] );
203             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  2 ], A_Q12_tmp[ 1 ] );
204             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  3 ], A_Q12_tmp[ 2 ] );
205             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  4 ], A_Q12_tmp[ 3 ] );
206             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  5 ], A_Q12_tmp[ 4 ] );
207             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  6 ], A_Q12_tmp[ 5 ] );
208             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  7 ], A_Q12_tmp[ 6 ] );
209             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  8 ], A_Q12_tmp[ 7 ] );
210             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i -  9 ], A_Q12_tmp[ 8 ] );
211             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 10 ], A_Q12_tmp[ 9 ] );
212             if( psDec->LPC_order == 16 ) {
213                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 11 ], A_Q12_tmp[ 10 ] );
214                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 12 ], A_Q12_tmp[ 11 ] );
215                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 13 ], A_Q12_tmp[ 12 ] );
216                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 14 ], A_Q12_tmp[ 13 ] );
217                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 15 ], A_Q12_tmp[ 14 ] );
218                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 16 ], A_Q12_tmp[ 15 ] );
219             }
220 
221             /* Add prediction to LPC excitation */
222             sLPC_Q14[ MAX_LPC_ORDER + i ] = silk_ADD_SAT32( pres_Q14[ i ], silk_LSHIFT_SAT32( LPC_pred_Q10, 4 ) );
223 
224             /* Scale with gain */
225             pxq[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14[ MAX_LPC_ORDER + i ], Gain_Q10 ), 8 ) );
226         }
227 
228         /* DEBUG_STORE_DATA( dec.pcm, pxq, psDec->subfr_length * sizeof( opus_int16 ) ) */
229 
230         /* Update LPC filter state */
231         silk_memcpy( sLPC_Q14, &sLPC_Q14[ psDec->subfr_length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
232         pexc_Q14 += psDec->subfr_length;
233         pxq      += psDec->subfr_length;
234     }
235 
236     /* Save LPC state */
237     silk_memcpy( psDec->sLPC_Q14_buf, sLPC_Q14, MAX_LPC_ORDER * sizeof( opus_int32 ) );
238     RESTORE_STACK;
239 }
240