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opus_silk.c
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1 /*
2  * Copyright (c) 2012 Andrew D'Addesio
3  * Copyright (c) 2013-2014 Mozilla Corporation
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Opus SILK decoder
25  */
26 
27 #include <stdint.h>
28 
29 #include "opus.h"
30 
31 typedef struct SilkFrame {
32  int coded;
33  int log_gain;
34  int16_t nlsf[16];
35  float lpc[16];
36 
37  float output [2 * SILK_HISTORY];
38  float lpc_history[2 * SILK_HISTORY];
39  int primarylag;
40 
41  int prev_voiced;
42 } SilkFrame;
43 
44 struct SilkContext {
45  AVCodecContext *avctx;
46  int output_channels;
47 
48  int midonly;
49  int subframes;
50  int sflength;
51  int flength;
52  int nlsf_interp_factor;
53 
54  enum OpusBandwidth bandwidth;
55  int wb;
56 
57  SilkFrame frame[2];
58  float prev_stereo_weights[2];
59  float stereo_weights[2];
60 
61  int prev_coded_channels;
62 };
63 
64 static const uint16_t silk_model_stereo_s1[] = {
65  256, 7, 9, 10, 11, 12, 22, 46, 54, 55, 56, 59, 82, 174, 197, 200,
66  201, 202, 210, 234, 244, 245, 246, 247, 249, 256
67 };
68 
69 static const uint16_t silk_model_stereo_s2[] = {256, 85, 171, 256};
70 
71 static const uint16_t silk_model_stereo_s3[] = {256, 51, 102, 154, 205, 256};
72 
73 static const uint16_t silk_model_mid_only[] = {256, 192, 256};
74 
75 static const uint16_t silk_model_frame_type_inactive[] = {256, 26, 256};
76 
77 static const uint16_t silk_model_frame_type_active[] = {256, 24, 98, 246, 256};
78 
79 static const uint16_t silk_model_gain_highbits[3][9] = {
80  {256, 32, 144, 212, 241, 253, 254, 255, 256},
81  {256, 2, 19, 64, 124, 186, 233, 252, 256},
82  {256, 1, 4, 30, 101, 195, 245, 254, 256}
83 };
84 
85 static const uint16_t silk_model_gain_lowbits[] = {256, 32, 64, 96, 128, 160, 192, 224, 256};
86 
87 static const uint16_t silk_model_gain_delta[] = {
88  256, 6, 11, 22, 53, 185, 206, 214, 218, 221, 223, 225, 227, 228, 229, 230,
89  231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246,
90  247, 248, 249, 250, 251, 252, 253, 254, 255, 256
91 };
92 static const uint16_t silk_model_lsf_s1[2][2][33] = {
93  {
94  { // NB or MB, unvoiced
95  256, 44, 78, 108, 127, 148, 160, 171, 174, 177, 179, 195, 197, 199, 200, 205,
96  207, 208, 211, 214, 215, 216, 218, 220, 222, 225, 226, 235, 244, 246, 253, 255, 256
97  }, { // NB or MB, voiced
98  256, 1, 11, 12, 20, 23, 31, 39, 53, 66, 80, 81, 95, 107, 120, 131,
99  142, 154, 165, 175, 185, 196, 204, 213, 221, 228, 236, 237, 238, 244, 245, 251, 256
100  }
101  }, {
102  { // WB, unvoiced
103  256, 31, 52, 55, 72, 73, 81, 98, 102, 103, 121, 137, 141, 143, 146, 147,
104  157, 158, 161, 177, 188, 204, 206, 208, 211, 213, 224, 225, 229, 238, 246, 253, 256
105  }, { // WB, voiced
106  256, 1, 5, 21, 26, 44, 55, 60, 74, 89, 90, 93, 105, 118, 132, 146,
107  152, 166, 178, 180, 186, 187, 199, 211, 222, 232, 235, 245, 250, 251, 252, 253, 256
108  }
109  }
110 };
111 
112 static const uint16_t silk_model_lsf_s2[32][10] = {
113  // NB, MB
114  { 256, 1, 2, 3, 18, 242, 253, 254, 255, 256 },
115  { 256, 1, 2, 4, 38, 221, 253, 254, 255, 256 },
116  { 256, 1, 2, 6, 48, 197, 252, 254, 255, 256 },
117  { 256, 1, 2, 10, 62, 185, 246, 254, 255, 256 },
118  { 256, 1, 4, 20, 73, 174, 248, 254, 255, 256 },
119  { 256, 1, 4, 21, 76, 166, 239, 254, 255, 256 },
120  { 256, 1, 8, 32, 85, 159, 226, 252, 255, 256 },
121  { 256, 1, 2, 20, 83, 161, 219, 249, 255, 256 },
122 
123  // WB
124  { 256, 1, 2, 3, 12, 244, 253, 254, 255, 256 },
125  { 256, 1, 2, 4, 32, 218, 253, 254, 255, 256 },
126  { 256, 1, 2, 5, 47, 199, 252, 254, 255, 256 },
127  { 256, 1, 2, 12, 61, 187, 252, 254, 255, 256 },
128  { 256, 1, 5, 24, 72, 172, 249, 254, 255, 256 },
129  { 256, 1, 2, 16, 70, 170, 242, 254, 255, 256 },
130  { 256, 1, 2, 17, 78, 165, 226, 251, 255, 256 },
131  { 256, 1, 8, 29, 79, 156, 237, 254, 255, 256 }
132 };
133 
134 static const uint16_t silk_model_lsf_s2_ext[] = { 256, 156, 216, 240, 249, 253, 255, 256 };
135 
136 static const uint16_t silk_model_lsf_interpolation_offset[] = { 256, 13, 35, 64, 75, 256 };
137 
138 static const uint16_t silk_model_pitch_highbits[] = {
139  256, 3, 6, 12, 23, 44, 74, 106, 125, 136, 146, 158, 171, 184, 196, 207,
140  216, 224, 231, 237, 241, 243, 245, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256
141 };
142 
143 static const uint16_t silk_model_pitch_lowbits_nb[]= { 256, 64, 128, 192, 256 };
144 
145 static const uint16_t silk_model_pitch_lowbits_mb[]= { 256, 43, 85, 128, 171, 213, 256 };
146 
147 static const uint16_t silk_model_pitch_lowbits_wb[]= { 256, 32, 64, 96, 128, 160, 192, 224, 256 };
148 
149 static const uint16_t silk_model_pitch_delta[] = {
150  256, 46, 48, 50, 53, 57, 63, 73, 88, 114, 152, 182, 204, 219, 229, 236,
151  242, 246, 250, 252, 254, 256
152 };
153 
154 static const uint16_t silk_model_pitch_contour_nb10ms[] = { 256, 143, 193, 256 };
155 
156 static const uint16_t silk_model_pitch_contour_nb20ms[] = {
157  256, 68, 80, 101, 118, 137, 159, 189, 213, 230, 246, 256
158 };
159 
160 static const uint16_t silk_model_pitch_contour_mbwb10ms[] = {
161  256, 91, 137, 176, 195, 209, 221, 229, 236, 242, 247, 252, 256
162 };
163 
164 static const uint16_t silk_model_pitch_contour_mbwb20ms[] = {
165  256, 33, 55, 73, 89, 104, 118, 132, 145, 158, 168, 177, 186, 194, 200, 206,
166  212, 217, 221, 225, 229, 232, 235, 238, 240, 242, 244, 246, 248, 250, 252, 253,
167  254, 255, 256
168 };
169 
170 static const uint16_t silk_model_ltp_filter[] = { 256, 77, 157, 256 };
171 
172 static const uint16_t silk_model_ltp_filter0_sel[] = {
173  256, 185, 200, 213, 226, 235, 244, 250, 256
174 };
175 
176 static const uint16_t silk_model_ltp_filter1_sel[] = {
177  256, 57, 91, 112, 132, 147, 160, 172, 185, 195, 205, 214, 224, 233, 241, 248, 256
178 };
179 
180 static const uint16_t silk_model_ltp_filter2_sel[] = {
181  256, 15, 31, 45, 57, 69, 81, 92, 103, 114, 124, 133, 142, 151, 160, 168,
182  176, 184, 192, 199, 206, 212, 218, 223, 227, 232, 236, 240, 244, 247, 251, 254, 256
183 };
184 
185 static const uint16_t silk_model_ltp_scale_index[] = { 256, 128, 192, 256 };
186 
187 static const uint16_t silk_model_lcg_seed[] = { 256, 64, 128, 192, 256 };
188 
189 static const uint16_t silk_model_exc_rate[2][10] = {
190  { 256, 15, 66, 78, 124, 169, 182, 215, 242, 256 }, // unvoiced
191  { 256, 33, 63, 99, 116, 150, 199, 217, 238, 256 } // voiced
192 };
193 
194 static const uint16_t silk_model_pulse_count[11][19] = {
195  { 256, 131, 205, 230, 238, 241, 244, 245, 246,
196  247, 248, 249, 250, 251, 252, 253, 254, 255, 256 },
197  { 256, 58, 151, 211, 234, 241, 244, 245, 246,
198  247, 248, 249, 250, 251, 252, 253, 254, 255, 256 },
199  { 256, 43, 94, 140, 173, 197, 213, 224, 232,
200  238, 241, 244, 247, 249, 250, 251, 253, 254, 256 },
201  { 256, 17, 69, 140, 197, 228, 240, 245, 246,
202  247, 248, 249, 250, 251, 252, 253, 254, 255, 256 },
203  { 256, 6, 27, 68, 121, 170, 205, 226, 237,
204  243, 246, 248, 250, 251, 252, 253, 254, 255, 256 },
205  { 256, 7, 21, 43, 71, 100, 128, 153, 173,
206  190, 203, 214, 223, 230, 235, 239, 243, 246, 256 },
207  { 256, 2, 7, 21, 50, 92, 138, 179, 210,
208  229, 240, 246, 249, 251, 252, 253, 254, 255, 256 },
209  { 256, 1, 3, 7, 17, 36, 65, 100, 137,
210  171, 199, 219, 233, 241, 246, 250, 252, 254, 256 },
211  { 256, 1, 3, 5, 10, 19, 33, 53, 77,
212  104, 132, 158, 181, 201, 216, 227, 235, 241, 256 },
213  { 256, 1, 2, 3, 9, 36, 94, 150, 189,
214  214, 228, 238, 244, 247, 250, 252, 253, 254, 256 },
215  { 256, 2, 3, 9, 36, 94, 150, 189, 214,
216  228, 238, 244, 247, 250, 252, 253, 254, 256, 256 }
217 };
218 
219 static const uint16_t silk_model_pulse_location[4][168] = {
220  {
221  256, 126, 256,
222  256, 56, 198, 256,
223  256, 25, 126, 230, 256,
224  256, 12, 72, 180, 244, 256,
225  256, 7, 42, 126, 213, 250, 256,
226  256, 4, 24, 83, 169, 232, 253, 256,
227  256, 3, 15, 53, 125, 200, 242, 254, 256,
228  256, 2, 10, 35, 89, 162, 221, 248, 255, 256,
229  256, 2, 7, 24, 63, 126, 191, 233, 251, 255, 256,
230  256, 1, 5, 17, 45, 94, 157, 211, 241, 252, 255, 256,
231  256, 1, 5, 13, 33, 70, 125, 182, 223, 245, 253, 255, 256,
232  256, 1, 4, 11, 26, 54, 98, 151, 199, 232, 248, 254, 255, 256,
233  256, 1, 3, 9, 21, 42, 77, 124, 172, 212, 237, 249, 254, 255, 256,
234  256, 1, 2, 6, 16, 33, 60, 97, 144, 187, 220, 241, 250, 254, 255, 256,
235  256, 1, 2, 3, 11, 25, 47, 80, 120, 163, 201, 229, 245, 253, 254, 255, 256,
236  256, 1, 2, 3, 4, 17, 35, 62, 98, 139, 180, 214, 238, 252, 253, 254, 255, 256
237  },{
238  256, 127, 256,
239  256, 53, 202, 256,
240  256, 22, 127, 233, 256,
241  256, 11, 72, 183, 246, 256,
242  256, 6, 41, 127, 215, 251, 256,
243  256, 4, 24, 83, 170, 232, 253, 256,
244  256, 3, 16, 56, 127, 200, 241, 254, 256,
245  256, 3, 12, 39, 92, 162, 218, 246, 255, 256,
246  256, 3, 11, 30, 67, 124, 185, 229, 249, 255, 256,
247  256, 3, 10, 25, 53, 97, 151, 200, 233, 250, 255, 256,
248  256, 1, 8, 21, 43, 77, 123, 171, 209, 237, 251, 255, 256,
249  256, 1, 2, 13, 35, 62, 97, 139, 186, 219, 244, 254, 255, 256,
250  256, 1, 2, 8, 22, 48, 85, 128, 171, 208, 234, 248, 254, 255, 256,
251  256, 1, 2, 6, 16, 36, 67, 107, 149, 189, 220, 240, 250, 254, 255, 256,
252  256, 1, 2, 5, 13, 29, 55, 90, 128, 166, 201, 227, 243, 251, 254, 255, 256,
253  256, 1, 2, 4, 10, 22, 43, 73, 109, 147, 183, 213, 234, 246, 252, 254, 255, 256
254  },{
255  256, 127, 256,
256  256, 49, 206, 256,
257  256, 20, 127, 236, 256,
258  256, 11, 71, 184, 246, 256,
259  256, 7, 43, 127, 214, 250, 256,
260  256, 6, 30, 87, 169, 229, 252, 256,
261  256, 5, 23, 62, 126, 194, 236, 252, 256,
262  256, 6, 20, 49, 96, 157, 209, 239, 253, 256,
263  256, 1, 16, 39, 74, 125, 175, 215, 245, 255, 256,
264  256, 1, 2, 23, 55, 97, 149, 195, 236, 254, 255, 256,
265  256, 1, 7, 23, 50, 86, 128, 170, 206, 233, 249, 255, 256,
266  256, 1, 6, 18, 39, 70, 108, 148, 186, 217, 238, 250, 255, 256,
267  256, 1, 4, 13, 30, 56, 90, 128, 166, 200, 226, 243, 252, 255, 256,
268  256, 1, 4, 11, 25, 47, 76, 110, 146, 180, 209, 231, 245, 252, 255, 256,
269  256, 1, 3, 8, 19, 37, 62, 93, 128, 163, 194, 219, 237, 248, 253, 255, 256,
270  256, 1, 2, 6, 15, 30, 51, 79, 111, 145, 177, 205, 226, 241, 250, 254, 255, 256
271  },{
272  256, 128, 256,
273  256, 42, 214, 256,
274  256, 21, 128, 235, 256,
275  256, 12, 72, 184, 245, 256,
276  256, 8, 42, 128, 214, 249, 256,
277  256, 8, 31, 86, 176, 231, 251, 256,
278  256, 5, 20, 58, 130, 202, 238, 253, 256,
279  256, 6, 18, 45, 97, 174, 221, 241, 251, 256,
280  256, 6, 25, 53, 88, 128, 168, 203, 231, 250, 256,
281  256, 4, 18, 40, 71, 108, 148, 185, 216, 238, 252, 256,
282  256, 3, 13, 31, 57, 90, 128, 166, 199, 225, 243, 253, 256,
283  256, 2, 10, 23, 44, 73, 109, 147, 183, 212, 233, 246, 254, 256,
284  256, 1, 6, 16, 33, 58, 90, 128, 166, 198, 223, 240, 250, 255, 256,
285  256, 1, 5, 12, 25, 46, 75, 110, 146, 181, 210, 231, 244, 251, 255, 256,
286  256, 1, 3, 8, 18, 35, 60, 92, 128, 164, 196, 221, 238, 248, 253, 255, 256,
287  256, 1, 3, 7, 14, 27, 48, 76, 110, 146, 180, 208, 229, 242, 249, 253, 255, 256
288  }
289 };
290 
291 static const uint16_t silk_model_excitation_lsb[] = {256, 136, 256};
292 
293 static const uint16_t silk_model_excitation_sign[3][2][7][3] = {
294  { // Inactive
295  { // Low offset
296  {256, 2, 256},
297  {256, 207, 256},
298  {256, 189, 256},
299  {256, 179, 256},
300  {256, 174, 256},
301  {256, 163, 256},
302  {256, 157, 256}
303  }, { // High offset
304  {256, 58, 256},
305  {256, 245, 256},
306  {256, 238, 256},
307  {256, 232, 256},
308  {256, 225, 256},
309  {256, 220, 256},
310  {256, 211, 256}
311  }
312  }, { // Unvoiced
313  { // Low offset
314  {256, 1, 256},
315  {256, 210, 256},
316  {256, 190, 256},
317  {256, 178, 256},
318  {256, 169, 256},
319  {256, 162, 256},
320  {256, 152, 256}
321  }, { // High offset
322  {256, 48, 256},
323  {256, 242, 256},
324  {256, 235, 256},
325  {256, 224, 256},
326  {256, 214, 256},
327  {256, 205, 256},
328  {256, 190, 256}
329  }
330  }, { // Voiced
331  { // Low offset
332  {256, 1, 256},
333  {256, 162, 256},
334  {256, 152, 256},
335  {256, 147, 256},
336  {256, 144, 256},
337  {256, 141, 256},
338  {256, 138, 256}
339  }, { // High offset
340  {256, 8, 256},
341  {256, 203, 256},
342  {256, 187, 256},
343  {256, 176, 256},
344  {256, 168, 256},
345  {256, 161, 256},
346  {256, 154, 256}
347  }
348  }
349 };
350 
351 static const int16_t silk_stereo_weights[] = {
352  -13732, -10050, -8266, -7526, -6500, -5000, -2950, -820,
353  820, 2950, 5000, 6500, 7526, 8266, 10050, 13732
354 };
355 
356 static const uint8_t silk_lsf_s2_model_sel_nbmb[32][10] = {
357  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
358  { 1, 3, 1, 2, 2, 1, 2, 1, 1, 1 },
359  { 2, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
360  { 1, 2, 2, 2, 2, 1, 2, 1, 1, 1 },
361  { 2, 3, 3, 3, 3, 2, 2, 2, 2, 2 },
362  { 0, 5, 3, 3, 2, 2, 2, 2, 1, 1 },
363  { 0, 2, 2, 2, 2, 2, 2, 2, 2, 1 },
364  { 2, 3, 6, 4, 4, 4, 5, 4, 5, 5 },
365  { 2, 4, 5, 5, 4, 5, 4, 6, 4, 4 },
366  { 2, 4, 4, 7, 4, 5, 4, 5, 5, 4 },
367  { 4, 3, 3, 3, 2, 3, 2, 2, 2, 2 },
368  { 1, 5, 5, 6, 4, 5, 4, 5, 5, 5 },
369  { 2, 7, 4, 6, 5, 5, 5, 5, 5, 5 },
370  { 2, 7, 5, 5, 5, 5, 5, 6, 5, 4 },
371  { 3, 3, 5, 4, 4, 5, 4, 5, 4, 4 },
372  { 2, 3, 3, 5, 5, 4, 4, 4, 4, 4 },
373  { 2, 4, 4, 6, 4, 5, 4, 5, 5, 5 },
374  { 2, 5, 4, 6, 5, 5, 5, 4, 5, 4 },
375  { 2, 7, 4, 5, 4, 5, 4, 5, 5, 5 },
376  { 2, 5, 4, 6, 7, 6, 5, 6, 5, 4 },
377  { 3, 6, 7, 4, 6, 5, 5, 6, 4, 5 },
378  { 2, 7, 6, 4, 4, 4, 5, 4, 5, 5 },
379  { 4, 5, 5, 4, 6, 6, 5, 6, 5, 4 },
380  { 2, 5, 5, 6, 5, 6, 4, 6, 4, 4 },
381  { 4, 5, 5, 5, 3, 7, 4, 5, 5, 4 },
382  { 2, 3, 4, 5, 5, 6, 4, 5, 5, 4 },
383  { 2, 3, 2, 3, 3, 4, 2, 3, 3, 3 },
384  { 1, 1, 2, 2, 2, 2, 2, 3, 2, 2 },
385  { 4, 5, 5, 6, 6, 6, 5, 6, 4, 5 },
386  { 3, 5, 5, 4, 4, 4, 4, 3, 3, 2 },
387  { 2, 5, 3, 7, 5, 5, 4, 4, 5, 4 },
388  { 4, 4, 5, 4, 5, 6, 5, 6, 5, 4 }
389 };
390 
391 static const uint8_t silk_lsf_s2_model_sel_wb[32][16] = {
392  { 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 },
393  { 10, 11, 11, 11, 11, 11, 10, 10, 10, 10, 10, 9, 9, 9, 8, 11 },
394  { 10, 13, 13, 11, 15, 12, 12, 13, 10, 13, 12, 13, 13, 12, 11, 11 },
395  { 8, 10, 9, 10, 10, 9, 9, 9, 9, 9, 8, 8, 8, 8, 8, 9 },
396  { 8, 14, 13, 12, 14, 12, 15, 13, 12, 12, 12, 13, 13, 12, 12, 11 },
397  { 8, 11, 13, 13, 12, 11, 11, 13, 11, 11, 11, 11, 11, 11, 10, 12 },
398  { 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 },
399  { 8, 10, 14, 11, 15, 10, 13, 11, 12, 13, 13, 12, 11, 11, 10, 11 },
400  { 8, 14, 10, 14, 14, 12, 13, 12, 14, 13, 12, 12, 13, 11, 11, 11 },
401  { 10, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 },
402  { 8, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9 },
403  { 10, 10, 11, 12, 13, 11, 11, 11, 11, 11, 11, 11, 10, 10, 9, 11 },
404  { 10, 10, 11, 11, 12, 11, 11, 11, 11, 11, 11, 11, 11, 10, 9, 11 },
405  { 11, 12, 12, 12, 14, 12, 12, 13, 11, 13, 12, 12, 13, 12, 11, 12 },
406  { 8, 14, 12, 13, 12, 15, 13, 10, 14, 13, 15, 12, 12, 11, 13, 11 },
407  { 8, 9, 8, 9, 9, 9, 9, 9, 9, 9, 8, 8, 8, 8, 9, 8 },
408  { 9, 14, 13, 15, 13, 12, 13, 11, 12, 13, 12, 12, 12, 11, 11, 12 },
409  { 9, 11, 11, 12, 12, 11, 11, 13, 10, 11, 11, 13, 13, 13, 11, 12 },
410  { 10, 11, 11, 10, 10, 10, 11, 10, 9, 10, 9, 10, 9, 9, 9, 12 },
411  { 8, 10, 11, 13, 11, 11, 10, 10, 10, 9, 9, 8, 8, 8, 8, 8 },
412  { 11, 12, 11, 13, 11, 11, 10, 10, 9, 9, 9, 9, 9, 10, 10, 12 },
413  { 10, 14, 11, 15, 15, 12, 13, 12, 13, 11, 13, 11, 11, 10, 11, 11 },
414  { 10, 11, 13, 14, 14, 11, 13, 11, 12, 12, 11, 11, 11, 11, 10, 12 },
415  { 9, 11, 11, 12, 12, 12, 12, 11, 13, 13, 13, 11, 9, 9, 9, 9 },
416  { 10, 13, 11, 14, 14, 12, 15, 12, 12, 13, 11, 12, 12, 11, 11, 11 },
417  { 8, 14, 9, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 },
418  { 8, 14, 14, 11, 13, 10, 13, 13, 11, 12, 12, 15, 15, 12, 12, 12 },
419  { 11, 11, 15, 11, 13, 12, 11, 11, 11, 10, 10, 11, 11, 11, 10, 11 },
420  { 8, 8, 9, 8, 8, 8, 10, 9, 10, 9, 9, 10, 10, 10, 9, 9 },
421  { 8, 11, 10, 13, 11, 11, 10, 11, 10, 9, 8, 8, 9, 8, 8, 9 },
422  { 11, 13, 13, 12, 15, 13, 11, 11, 10, 11, 10, 10, 9, 8, 9, 8 },
423  { 10, 11, 13, 11, 12, 11, 11, 11, 10, 9, 10, 14, 12, 8, 8, 8 }
424 };
425 
426 static const uint8_t silk_lsf_pred_weights_nbmb[2][9] = {
427  {179, 138, 140, 148, 151, 149, 153, 151, 163},
428  {116, 67, 82, 59, 92, 72, 100, 89, 92}
429 };
430 
431 static const uint8_t silk_lsf_pred_weights_wb[2][15] = {
432  {175, 148, 160, 176, 178, 173, 174, 164, 177, 174, 196, 182, 198, 192, 182},
433  { 68, 62, 66, 60, 72, 117, 85, 90, 118, 136, 151, 142, 160, 142, 155}
434 };
435 
436 static const uint8_t silk_lsf_weight_sel_nbmb[32][9] = {
437  { 0, 1, 0, 0, 0, 0, 0, 0, 0 },
438  { 1, 0, 0, 0, 0, 0, 0, 0, 0 },
439  { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
440  { 1, 1, 1, 0, 0, 0, 0, 1, 0 },
441  { 0, 1, 0, 0, 0, 0, 0, 0, 0 },
442  { 0, 1, 0, 0, 0, 0, 0, 0, 0 },
443  { 1, 0, 1, 1, 0, 0, 0, 1, 0 },
444  { 0, 1, 1, 0, 0, 1, 1, 0, 0 },
445  { 0, 0, 1, 1, 0, 1, 0, 1, 1 },
446  { 0, 0, 1, 1, 0, 0, 1, 1, 1 },
447  { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
448  { 0, 1, 0, 1, 1, 1, 1, 1, 0 },
449  { 0, 1, 0, 1, 1, 1, 1, 1, 0 },
450  { 0, 1, 1, 1, 1, 1, 1, 1, 0 },
451  { 1, 0, 1, 1, 0, 1, 1, 1, 1 },
452  { 0, 1, 1, 1, 1, 1, 0, 1, 0 },
453  { 0, 0, 1, 1, 0, 1, 0, 1, 0 },
454  { 0, 0, 1, 1, 1, 0, 1, 1, 1 },
455  { 0, 1, 1, 0, 0, 1, 1, 1, 0 },
456  { 0, 0, 0, 1, 1, 1, 0, 1, 0 },
457  { 0, 1, 1, 0, 0, 1, 0, 1, 0 },
458  { 0, 1, 1, 0, 0, 0, 1, 1, 0 },
459  { 0, 0, 0, 0, 0, 1, 1, 1, 1 },
460  { 0, 0, 1, 1, 0, 0, 0, 1, 1 },
461  { 0, 0, 0, 1, 0, 1, 1, 1, 1 },
462  { 0, 1, 1, 1, 1, 1, 1, 1, 0 },
463  { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
464  { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
465  { 0, 0, 1, 0, 1, 1, 0, 1, 0 },
466  { 1, 0, 0, 1, 0, 0, 0, 0, 0 },
467  { 0, 0, 0, 1, 1, 0, 1, 0, 1 },
468  { 1, 0, 1, 1, 0, 1, 1, 1, 1 }
469 };
470 
471 static const uint8_t silk_lsf_weight_sel_wb[32][15] = {
472  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
473  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
474  { 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0 },
475  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 },
476  { 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0 },
477  { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
478  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0 },
479  { 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1 },
480  { 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1 },
481  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
482  { 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
483  { 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0 },
484  { 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0 },
485  { 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0 },
486  { 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1 },
487  { 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0 },
488  { 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0 },
489  { 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0 },
490  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
491  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 },
492  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
493  { 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0 },
494  { 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0 },
495  { 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0 },
496  { 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1 },
497  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
498  { 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1 },
499  { 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1 },
500  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
501  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
502  { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 },
503  { 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0 }
504 };
505 
506 static const uint8_t silk_lsf_codebook_nbmb[32][10] = {
507  { 12, 35, 60, 83, 108, 132, 157, 180, 206, 228 },
508  { 15, 32, 55, 77, 101, 125, 151, 175, 201, 225 },
509  { 19, 42, 66, 89, 114, 137, 162, 184, 209, 230 },
510  { 12, 25, 50, 72, 97, 120, 147, 172, 200, 223 },
511  { 26, 44, 69, 90, 114, 135, 159, 180, 205, 225 },
512  { 13, 22, 53, 80, 106, 130, 156, 180, 205, 228 },
513  { 15, 25, 44, 64, 90, 115, 142, 168, 196, 222 },
514  { 19, 24, 62, 82, 100, 120, 145, 168, 190, 214 },
515  { 22, 31, 50, 79, 103, 120, 151, 170, 203, 227 },
516  { 21, 29, 45, 65, 106, 124, 150, 171, 196, 224 },
517  { 30, 49, 75, 97, 121, 142, 165, 186, 209, 229 },
518  { 19, 25, 52, 70, 93, 116, 143, 166, 192, 219 },
519  { 26, 34, 62, 75, 97, 118, 145, 167, 194, 217 },
520  { 25, 33, 56, 70, 91, 113, 143, 165, 196, 223 },
521  { 21, 34, 51, 72, 97, 117, 145, 171, 196, 222 },
522  { 20, 29, 50, 67, 90, 117, 144, 168, 197, 221 },
523  { 22, 31, 48, 66, 95, 117, 146, 168, 196, 222 },
524  { 24, 33, 51, 77, 116, 134, 158, 180, 200, 224 },
525  { 21, 28, 70, 87, 106, 124, 149, 170, 194, 217 },
526  { 26, 33, 53, 64, 83, 117, 152, 173, 204, 225 },
527  { 27, 34, 65, 95, 108, 129, 155, 174, 210, 225 },
528  { 20, 26, 72, 99, 113, 131, 154, 176, 200, 219 },
529  { 34, 43, 61, 78, 93, 114, 155, 177, 205, 229 },
530  { 23, 29, 54, 97, 124, 138, 163, 179, 209, 229 },
531  { 30, 38, 56, 89, 118, 129, 158, 178, 200, 231 },
532  { 21, 29, 49, 63, 85, 111, 142, 163, 193, 222 },
533  { 27, 48, 77, 103, 133, 158, 179, 196, 215, 232 },
534  { 29, 47, 74, 99, 124, 151, 176, 198, 220, 237 },
535  { 33, 42, 61, 76, 93, 121, 155, 174, 207, 225 },
536  { 29, 53, 87, 112, 136, 154, 170, 188, 208, 227 },
537  { 24, 30, 52, 84, 131, 150, 166, 186, 203, 229 },
538  { 37, 48, 64, 84, 104, 118, 156, 177, 201, 230 }
539 };
540 
541 static const uint8_t silk_lsf_codebook_wb[32][16] = {
542  { 7, 23, 38, 54, 69, 85, 100, 116, 131, 147, 162, 178, 193, 208, 223, 239 },
543  { 13, 25, 41, 55, 69, 83, 98, 112, 127, 142, 157, 171, 187, 203, 220, 236 },
544  { 15, 21, 34, 51, 61, 78, 92, 106, 126, 136, 152, 167, 185, 205, 225, 240 },
545  { 10, 21, 36, 50, 63, 79, 95, 110, 126, 141, 157, 173, 189, 205, 221, 237 },
546  { 17, 20, 37, 51, 59, 78, 89, 107, 123, 134, 150, 164, 184, 205, 224, 240 },
547  { 10, 15, 32, 51, 67, 81, 96, 112, 129, 142, 158, 173, 189, 204, 220, 236 },
548  { 8, 21, 37, 51, 65, 79, 98, 113, 126, 138, 155, 168, 179, 192, 209, 218 },
549  { 12, 15, 34, 55, 63, 78, 87, 108, 118, 131, 148, 167, 185, 203, 219, 236 },
550  { 16, 19, 32, 36, 56, 79, 91, 108, 118, 136, 154, 171, 186, 204, 220, 237 },
551  { 11, 28, 43, 58, 74, 89, 105, 120, 135, 150, 165, 180, 196, 211, 226, 241 },
552  { 6, 16, 33, 46, 60, 75, 92, 107, 123, 137, 156, 169, 185, 199, 214, 225 },
553  { 11, 19, 30, 44, 57, 74, 89, 105, 121, 135, 152, 169, 186, 202, 218, 234 },
554  { 12, 19, 29, 46, 57, 71, 88, 100, 120, 132, 148, 165, 182, 199, 216, 233 },
555  { 17, 23, 35, 46, 56, 77, 92, 106, 123, 134, 152, 167, 185, 204, 222, 237 },
556  { 14, 17, 45, 53, 63, 75, 89, 107, 115, 132, 151, 171, 188, 206, 221, 240 },
557  { 9, 16, 29, 40, 56, 71, 88, 103, 119, 137, 154, 171, 189, 205, 222, 237 },
558  { 16, 19, 36, 48, 57, 76, 87, 105, 118, 132, 150, 167, 185, 202, 218, 236 },
559  { 12, 17, 29, 54, 71, 81, 94, 104, 126, 136, 149, 164, 182, 201, 221, 237 },
560  { 15, 28, 47, 62, 79, 97, 115, 129, 142, 155, 168, 180, 194, 208, 223, 238 },
561  { 8, 14, 30, 45, 62, 78, 94, 111, 127, 143, 159, 175, 192, 207, 223, 239 },
562  { 17, 30, 49, 62, 79, 92, 107, 119, 132, 145, 160, 174, 190, 204, 220, 235 },
563  { 14, 19, 36, 45, 61, 76, 91, 108, 121, 138, 154, 172, 189, 205, 222, 238 },
564  { 12, 18, 31, 45, 60, 76, 91, 107, 123, 138, 154, 171, 187, 204, 221, 236 },
565  { 13, 17, 31, 43, 53, 70, 83, 103, 114, 131, 149, 167, 185, 203, 220, 237 },
566  { 17, 22, 35, 42, 58, 78, 93, 110, 125, 139, 155, 170, 188, 206, 224, 240 },
567  { 8, 15, 34, 50, 67, 83, 99, 115, 131, 146, 162, 178, 193, 209, 224, 239 },
568  { 13, 16, 41, 66, 73, 86, 95, 111, 128, 137, 150, 163, 183, 206, 225, 241 },
569  { 17, 25, 37, 52, 63, 75, 92, 102, 119, 132, 144, 160, 175, 191, 212, 231 },
570  { 19, 31, 49, 65, 83, 100, 117, 133, 147, 161, 174, 187, 200, 213, 227, 242 },
571  { 18, 31, 52, 68, 88, 103, 117, 126, 138, 149, 163, 177, 192, 207, 223, 239 },
572  { 16, 29, 47, 61, 76, 90, 106, 119, 133, 147, 161, 176, 193, 209, 224, 240 },
573  { 15, 21, 35, 50, 61, 73, 86, 97, 110, 119, 129, 141, 175, 198, 218, 237 }
574 };
575 
576 static const uint16_t silk_lsf_min_spacing_nbmb[] = {
577  250, 3, 6, 3, 3, 3, 4, 3, 3, 3, 461
578 };
579 
580 static const uint16_t silk_lsf_min_spacing_wb[] = {
581  100, 3, 40, 3, 3, 3, 5, 14, 14, 10, 11, 3, 8, 9, 7, 3, 347
582 };
583 
584 static const uint8_t silk_lsf_ordering_nbmb[] = {
585  0, 9, 6, 3, 4, 5, 8, 1, 2, 7
586 };
587 
588 static const uint8_t silk_lsf_ordering_wb[] = {
589  0, 15, 8, 7, 4, 11, 12, 3, 2, 13, 10, 5, 6, 9, 14, 1
590 };
591 
592 static const int16_t silk_cosine[] = { /* (0.12) */
593  4096, 4095, 4091, 4085,
594  4076, 4065, 4052, 4036,
595  4017, 3997, 3973, 3948,
596  3920, 3889, 3857, 3822,
597  3784, 3745, 3703, 3659,
598  3613, 3564, 3513, 3461,
599  3406, 3349, 3290, 3229,
600  3166, 3102, 3035, 2967,
601  2896, 2824, 2751, 2676,
602  2599, 2520, 2440, 2359,
603  2276, 2191, 2106, 2019,
604  1931, 1842, 1751, 1660,
605  1568, 1474, 1380, 1285,
606  1189, 1093, 995, 897,
607  799, 700, 601, 501,
608  401, 301, 201, 101,
609  0, -101, -201, -301,
610  -401, -501, -601, -700,
611  -799, -897, -995, -1093,
612  -1189, -1285, -1380, -1474,
613  -1568, -1660, -1751, -1842,
614  -1931, -2019, -2106, -2191,
615  -2276, -2359, -2440, -2520,
616  -2599, -2676, -2751, -2824,
617  -2896, -2967, -3035, -3102,
618  -3166, -3229, -3290, -3349,
619  -3406, -3461, -3513, -3564,
620  -3613, -3659, -3703, -3745,
621  -3784, -3822, -3857, -3889,
622  -3920, -3948, -3973, -3997,
623  -4017, -4036, -4052, -4065,
624  -4076, -4085, -4091, -4095,
625  -4096
626 };
627 
628 static const uint16_t silk_pitch_scale[] = { 4, 6, 8};
629 
630 static const uint16_t silk_pitch_min_lag[] = { 16, 24, 32};
631 
632 static const uint16_t silk_pitch_max_lag[] = {144, 216, 288};
633 
634 static const int8_t silk_pitch_offset_nb10ms[3][2] = {
635  { 0, 0},
636  { 1, 0},
637  { 0, 1}
638 };
639 
640 static const int8_t silk_pitch_offset_nb20ms[11][4] = {
641  { 0, 0, 0, 0},
642  { 2, 1, 0, -1},
643  {-1, 0, 1, 2},
644  {-1, 0, 0, 1},
645  {-1, 0, 0, 0},
646  { 0, 0, 0, 1},
647  { 0, 0, 1, 1},
648  { 1, 1, 0, 0},
649  { 1, 0, 0, 0},
650  { 0, 0, 0, -1},
651  { 1, 0, 0, -1}
652 };
653 
654 static const int8_t silk_pitch_offset_mbwb10ms[12][2] = {
655  { 0, 0},
656  { 0, 1},
657  { 1, 0},
658  {-1, 1},
659  { 1, -1},
660  {-1, 2},
661  { 2, -1},
662  {-2, 2},
663  { 2, -2},
664  {-2, 3},
665  { 3, -2},
666  {-3, 3}
667 };
668 
669 static const int8_t silk_pitch_offset_mbwb20ms[34][4] = {
670  { 0, 0, 0, 0},
671  { 0, 0, 1, 1},
672  { 1, 1, 0, 0},
673  {-1, 0, 0, 0},
674  { 0, 0, 0, 1},
675  { 1, 0, 0, 0},
676  {-1, 0, 0, 1},
677  { 0, 0, 0, -1},
678  {-1, 0, 1, 2},
679  { 1, 0, 0, -1},
680  {-2, -1, 1, 2},
681  { 2, 1, 0, -1},
682  {-2, 0, 0, 2},
683  {-2, 0, 1, 3},
684  { 2, 1, -1, -2},
685  {-3, -1, 1, 3},
686  { 2, 0, 0, -2},
687  { 3, 1, 0, -2},
688  {-3, -1, 2, 4},
689  {-4, -1, 1, 4},
690  { 3, 1, -1, -3},
691  {-4, -1, 2, 5},
692  { 4, 2, -1, -3},
693  { 4, 1, -1, -4},
694  {-5, -1, 2, 6},
695  { 5, 2, -1, -4},
696  {-6, -2, 2, 6},
697  {-5, -2, 2, 5},
698  { 6, 2, -1, -5},
699  {-7, -2, 3, 8},
700  { 6, 2, -2, -6},
701  { 5, 2, -2, -5},
702  { 8, 3, -2, -7},
703  {-9, -3, 3, 9}
704 };
705 
706 static const int8_t silk_ltp_filter0_taps[8][5] = {
707  { 4, 6, 24, 7, 5},
708  { 0, 0, 2, 0, 0},
709  { 12, 28, 41, 13, -4},
710  { -9, 15, 42, 25, 14},
711  { 1, -2, 62, 41, -9},
712  {-10, 37, 65, -4, 3},
713  { -6, 4, 66, 7, -8},
714  { 16, 14, 38, -3, 33}
715 };
716 
717 static const int8_t silk_ltp_filter1_taps[16][5] = {
718  { 13, 22, 39, 23, 12},
719  { -1, 36, 64, 27, -6},
720  { -7, 10, 55, 43, 17},
721  { 1, 1, 8, 1, 1},
722  { 6, -11, 74, 53, -9},
723  {-12, 55, 76, -12, 8},
724  { -3, 3, 93, 27, -4},
725  { 26, 39, 59, 3, -8},
726  { 2, 0, 77, 11, 9},
727  { -8, 22, 44, -6, 7},
728  { 40, 9, 26, 3, 9},
729  { -7, 20, 101, -7, 4},
730  { 3, -8, 42, 26, 0},
731  {-15, 33, 68, 2, 23},
732  { -2, 55, 46, -2, 15},
733  { 3, -1, 21, 16, 41}
734 };
735 
736 static const int8_t silk_ltp_filter2_taps[32][5] = {
737  { -6, 27, 61, 39, 5},
738  {-11, 42, 88, 4, 1},
739  { -2, 60, 65, 6, -4},
740  { -1, -5, 73, 56, 1},
741  { -9, 19, 94, 29, -9},
742  { 0, 12, 99, 6, 4},
743  { 8, -19, 102, 46, -13},
744  { 3, 2, 13, 3, 2},
745  { 9, -21, 84, 72, -18},
746  {-11, 46, 104, -22, 8},
747  { 18, 38, 48, 23, 0},
748  {-16, 70, 83, -21, 11},
749  { 5, -11, 117, 22, -8},
750  { -6, 23, 117, -12, 3},
751  { 3, -8, 95, 28, 4},
752  {-10, 15, 77, 60, -15},
753  { -1, 4, 124, 2, -4},
754  { 3, 38, 84, 24, -25},
755  { 2, 13, 42, 13, 31},
756  { 21, -4, 56, 46, -1},
757  { -1, 35, 79, -13, 19},
758  { -7, 65, 88, -9, -14},
759  { 20, 4, 81, 49, -29},
760  { 20, 0, 75, 3, -17},
761  { 5, -9, 44, 92, -8},
762  { 1, -3, 22, 69, 31},
763  { -6, 95, 41, -12, 5},
764  { 39, 67, 16, -4, 1},
765  { 0, -6, 120, 55, -36},
766  {-13, 44, 122, 4, -24},
767  { 81, 5, 11, 3, 7},
768  { 2, 0, 9, 10, 88}
769 };
770 
771 static const uint16_t silk_ltp_scale_factor[] = {15565, 12288, 8192};
772 
773 static const uint8_t silk_shell_blocks[3][2] = {
774  { 5, 10}, // NB
775  { 8, 15}, // MB
776  {10, 20} // WB
777 };
778 
779 static const uint8_t silk_quant_offset[2][2] = { /* (0.23) */
780  {25, 60}, // Inactive or Unvoiced
781  { 8, 25} // Voiced
782 };
783 
784 static const int silk_stereo_interp_len[3] = {
785  64, 96, 128
786 };
787 
788 static inline void silk_stabilize_lsf(int16_t nlsf[16], int order, const uint16_t min_delta[17])
789 {
790  int pass, i;
791  for (pass = 0; pass < 20; pass++) {
792  int k, min_diff = 0;
793  for (i = 0; i < order+1; i++) {
794  int low = i != 0 ? nlsf[i-1] : 0;
795  int high = i != order ? nlsf[i] : 32768;
796  int diff = (high - low) - (min_delta[i]);
797 
798  if (diff < min_diff) {
799  min_diff = diff;
800  k = i;
801 
802  if (pass == 20)
803  break;
804  }
805  }
806  if (min_diff == 0) /* no issues; stabilized */
807  return;
808 
809  /* wiggle one or two LSFs */
810  if (k == 0) {
811  /* repel away from lower bound */
812  nlsf[0] = min_delta[0];
813  } else if (k == order) {
814  /* repel away from higher bound */
815  nlsf[order-1] = 32768 - min_delta[order];
816  } else {
817  /* repel away from current position */
818  int min_center = 0, max_center = 32768, center_val;
819 
820  /* lower extent */
821  for (i = 0; i < k; i++)
822  min_center += min_delta[i];
823  min_center += min_delta[k] >> 1;
824 
825  /* upper extent */
826  for (i = order; i > k; i--)
827  max_center -= min_delta[k];
828  max_center -= min_delta[k] >> 1;
829 
830  /* move apart */
831  center_val = nlsf[k - 1] + nlsf[k];
832  center_val = (center_val >> 1) + (center_val & 1); // rounded divide by 2
833  center_val = FFMIN(max_center, FFMAX(min_center, center_val));
834 
835  nlsf[k - 1] = center_val - (min_delta[k] >> 1);
836  nlsf[k] = nlsf[k - 1] + min_delta[k];
837  }
838  }
839 
840  /* resort to the fall-back method, the standard method for LSF stabilization */
841 
842  /* sort; as the LSFs should be nearly sorted, use insertion sort */
843  for (i = 1; i < order; i++) {
844  int j, value = nlsf[i];
845  for (j = i - 1; j >= 0 && nlsf[j] > value; j--)
846  nlsf[j + 1] = nlsf[j];
847  nlsf[j + 1] = value;
848  }
849 
850  /* push forwards to increase distance */
851  if (nlsf[0] < min_delta[0])
852  nlsf[0] = min_delta[0];
853  for (i = 1; i < order; i++)
854  if (nlsf[i] < nlsf[i - 1] + min_delta[i])
855  nlsf[i] = nlsf[i - 1] + min_delta[i];
856 
857  /* push backwards to increase distance */
858  if (nlsf[order-1] > 32768 - min_delta[order])
859  nlsf[order-1] = 32768 - min_delta[order];
860  for (i = order-2; i >= 0; i--)
861  if (nlsf[i] > nlsf[i + 1] - min_delta[i+1])
862  nlsf[i] = nlsf[i + 1] - min_delta[i+1];
863 
864  return;
865 }
866 
867 static inline int silk_is_lpc_stable(const int16_t lpc[16], int order)
868 {
869  int k, j, DC_resp = 0;
870  int32_t lpc32[2][16]; // Q24
871  int totalinvgain = 1 << 30; // 1.0 in Q30
872  int32_t *row = lpc32[0], *prevrow;
873 
874  /* initialize the first row for the Levinson recursion */
875  for (k = 0; k < order; k++) {
876  DC_resp += lpc[k];
877  row[k] = lpc[k] * 4096;
878  }
879 
880  if (DC_resp >= 4096)
881  return 0;
882 
883  /* check if prediction gain pushes any coefficients too far */
884  for (k = order - 1; 1; k--) {
885  int rc; // Q31; reflection coefficient
886  int gaindiv; // Q30; inverse of the gain (the divisor)
887  int gain; // gain for this reflection coefficient
888  int fbits; // fractional bits used for the gain
889  int error; // Q29; estimate of the error of our partial estimate of 1/gaindiv
890 
891  if (FFABS(row[k]) > 16773022)
892  return 0;
893 
894  rc = -(row[k] * 128);
895  gaindiv = (1 << 30) - MULH(rc, rc);
896 
897  totalinvgain = MULH(totalinvgain, gaindiv) << 2;
898  if (k == 0)
899  return (totalinvgain >= 107374);
900 
901  /* approximate 1.0/gaindiv */
902  fbits = opus_ilog(gaindiv);
903  gain = ((1 << 29) - 1) / (gaindiv >> (fbits + 1 - 16)); // Q<fbits-16>
904  error = (1 << 29) - MULL(gaindiv << (15 + 16 - fbits), gain, 16);
905  gain = ((gain << 16) + (error * gain >> 13));
906 
907  /* switch to the next row of the LPC coefficients */
908  prevrow = row;
909  row = lpc32[k & 1];
910 
911  for (j = 0; j < k; j++) {
912  int x = prevrow[j] - ROUND_MULL(prevrow[k - j - 1], rc, 31);
913  row[j] = ROUND_MULL(x, gain, fbits);
914  }
915  }
916 }
917 
918 static void silk_lsp2poly(const int32_t lsp[16], int32_t pol[16], int half_order)
919 {
920  int i, j;
921 
922  pol[0] = 65536; // 1.0 in Q16
923  pol[1] = -lsp[0];
924 
925  for (i = 1; i < half_order; i++) {
926  pol[i + 1] = pol[i - 1] * 2 - ROUND_MULL(lsp[2 * i], pol[i], 16);
927  for (j = i; j > 1; j--)
928  pol[j] += pol[j - 2] - ROUND_MULL(lsp[2 * i], pol[j - 1], 16);
929 
930  pol[1] -= lsp[2 * i];
931  }
932 }
933 
934 static void silk_lsf2lpc(const int16_t nlsf[16], float lpcf[16], int order)
935 {
936  int i, k;
937  int32_t lsp[16]; // Q17; 2*cos(LSF)
938  int32_t p[9], q[9]; // Q16
939  int32_t lpc32[16]; // Q17
940  int16_t lpc[16]; // Q12
941 
942  /* convert the LSFs to LSPs, i.e. 2*cos(LSF) */
943  for (k = 0; k < order; k++) {
944  int index = nlsf[k] >> 8;
945  int offset = nlsf[k] & 255;
946  int k2 = (order == 10) ? silk_lsf_ordering_nbmb[k] : silk_lsf_ordering_wb[k];
947 
948  /* interpolate and round */
949  lsp[k2] = silk_cosine[index] * 256;
950  lsp[k2] += (silk_cosine[index + 1] - silk_cosine[index]) * offset;
951  lsp[k2] = (lsp[k2] + 4) >> 3;
952  }
953 
954  silk_lsp2poly(lsp , p, order >> 1);
955  silk_lsp2poly(lsp + 1, q, order >> 1);
956 
957  /* reconstruct A(z) */
958  for (k = 0; k < order>>1; k++) {
959  lpc32[k] = -p[k + 1] - p[k] - q[k + 1] + q[k];
960  lpc32[order-k-1] = -p[k + 1] - p[k] + q[k + 1] - q[k];
961  }
962 
963  /* limit the range of the LPC coefficients to each fit within an int16_t */
964  for (i = 0; i < 10; i++) {
965  int j;
966  unsigned int maxabs = 0;
967  for (j = 0, k = 0; j < order; j++) {
968  unsigned int x = FFABS(lpc32[k]);
969  if (x > maxabs) {
970  maxabs = x; // Q17
971  k = j;
972  }
973  }
974 
975  maxabs = (maxabs + 16) >> 5; // convert to Q12
976 
977  if (maxabs > 32767) {
978  /* perform bandwidth expansion */
979  unsigned int chirp, chirp_base; // Q16
980  maxabs = FFMIN(maxabs, 163838); // anything above this overflows chirp's numerator
981  chirp_base = chirp = 65470 - ((maxabs - 32767) << 14) / ((maxabs * (k+1)) >> 2);
982 
983  for (k = 0; k < order; k++) {
984  lpc32[k] = ROUND_MULL(lpc32[k], chirp, 16);
985  chirp = (chirp_base * chirp + 32768) >> 16;
986  }
987  } else break;
988  }
989 
990  if (i == 10) {
991  /* time's up: just clamp */
992  for (k = 0; k < order; k++) {
993  int x = (lpc32[k] + 16) >> 5;
994  lpc[k] = av_clip_int16(x);
995  lpc32[k] = lpc[k] << 5; // shortcut mandated by the spec; drops lower 5 bits
996  }
997  } else {
998  for (k = 0; k < order; k++)
999  lpc[k] = (lpc32[k] + 16) >> 5;
1000  }
1001 
1002  /* if the prediction gain causes the LPC filter to become unstable,
1003  apply further bandwidth expansion on the Q17 coefficients */
1004  for (i = 1; i <= 16 && !silk_is_lpc_stable(lpc, order); i++) {
1005  unsigned int chirp, chirp_base;
1006  chirp_base = chirp = 65536 - (1 << i);
1007 
1008  for (k = 0; k < order; k++) {
1009  lpc32[k] = ROUND_MULL(lpc32[k], chirp, 16);
1010  lpc[k] = (lpc32[k] + 16) >> 5;
1011  chirp = (chirp_base * chirp + 32768) >> 16;
1012  }
1013  }
1014 
1015  for (i = 0; i < order; i++)
1016  lpcf[i] = lpc[i] / 4096.0f;
1017 }
1018 
1019 static inline void silk_decode_lpc(SilkContext *s, SilkFrame *frame,
1020  OpusRangeCoder *rc,
1021  float lpc_leadin[16], float lpc[16],
1022  int *lpc_order, int *has_lpc_leadin, int voiced)
1023 {
1024  int i;
1025  int order; // order of the LP polynomial; 10 for NB/MB and 16 for WB
1026  int8_t lsf_i1, lsf_i2[16]; // stage-1 and stage-2 codebook indices
1027  int16_t lsf_res[16]; // residual as a Q10 value
1028  int16_t nlsf[16]; // Q15
1029 
1030  *lpc_order = order = s->wb ? 16 : 10;
1031 
1032  /* obtain LSF stage-1 and stage-2 indices */
1033  lsf_i1 = opus_rc_getsymbol(rc, silk_model_lsf_s1[s->wb][voiced]);
1034  for (i = 0; i < order; i++) {
1035  int index = s->wb ? silk_lsf_s2_model_sel_wb [lsf_i1][i] :
1036  silk_lsf_s2_model_sel_nbmb[lsf_i1][i];
1037  lsf_i2[i] = opus_rc_getsymbol(rc, silk_model_lsf_s2[index]) - 4;
1038  if (lsf_i2[i] == -4)
1039  lsf_i2[i] -= opus_rc_getsymbol(rc, silk_model_lsf_s2_ext);
1040  else if (lsf_i2[i] == 4)
1041  lsf_i2[i] += opus_rc_getsymbol(rc, silk_model_lsf_s2_ext);
1042  }
1043 
1044  /* reverse the backwards-prediction step */
1045  for (i = order - 1; i >= 0; i--) {
1046  int qstep = s->wb ? 9830 : 11796;
1047 
1048  lsf_res[i] = lsf_i2[i] * 1024;
1049  if (lsf_i2[i] < 0) lsf_res[i] += 102;
1050  else if (lsf_i2[i] > 0) lsf_res[i] -= 102;
1051  lsf_res[i] = (lsf_res[i] * qstep) >> 16;
1052 
1053  if (i + 1 < order) {
1054  int weight = s->wb ? silk_lsf_pred_weights_wb [silk_lsf_weight_sel_wb [lsf_i1][i]][i] :
1055  silk_lsf_pred_weights_nbmb[silk_lsf_weight_sel_nbmb[lsf_i1][i]][i];
1056  lsf_res[i] += (lsf_res[i+1] * weight) >> 8;
1057  }
1058  }
1059 
1060  /* reconstruct the NLSF coefficients from the supplied indices */
1061  for (i = 0; i < order; i++) {
1062  const uint8_t * codebook = s->wb ? silk_lsf_codebook_wb [lsf_i1] :
1063  silk_lsf_codebook_nbmb[lsf_i1];
1064  int cur, prev, next, weight_sq, weight, ipart, fpart, y, value;
1065 
1066  /* find the weight of the residual */
1067  /* TODO: precompute */
1068  cur = codebook[i];
1069  prev = i ? codebook[i - 1] : 0;
1070  next = i + 1 < order ? codebook[i + 1] : 256;
1071  weight_sq = (1024 / (cur - prev) + 1024 / (next - cur)) << 16;
1072 
1073  /* approximate square-root with mandated fixed-point arithmetic */
1074  ipart = opus_ilog(weight_sq);
1075  fpart = (weight_sq >> (ipart-8)) & 127;
1076  y = ((ipart & 1) ? 32768 : 46214) >> ((32 - ipart)>>1);
1077  weight = y + ((213 * fpart * y) >> 16);
1078 
1079  value = cur * 128 + (lsf_res[i] * 16384) / weight;
1080  nlsf[i] = av_clip(value, 0, 32767);
1081  }
1082 
1083  /* stabilize the NLSF coefficients */
1084  silk_stabilize_lsf(nlsf, order, s->wb ? silk_lsf_min_spacing_wb :
1085  silk_lsf_min_spacing_nbmb);
1086 
1087  /* produce an interpolation for the first 2 subframes, */
1088  /* and then convert both sets of NLSFs to LPC coefficients */
1089  *has_lpc_leadin = 0;
1090  if (s->subframes == 4) {
1091  int offset = opus_rc_getsymbol(rc, silk_model_lsf_interpolation_offset);
1092  if (offset != 4 && frame->coded) {
1093  *has_lpc_leadin = 1;
1094  if (offset != 0) {
1095  int16_t nlsf_leadin[16];
1096  for (i = 0; i < order; i++)
1097  nlsf_leadin[i] = frame->nlsf[i] +
1098  ((nlsf[i] - frame->nlsf[i]) * offset >> 2);
1099  silk_lsf2lpc(nlsf_leadin, lpc_leadin, order);
1100  } else /* avoid re-computation for a (roughly) 1-in-4 occurrence */
1101  memcpy(lpc_leadin, frame->lpc, 16 * sizeof(float));
1102  } else
1103  offset = 4;
1104  s->nlsf_interp_factor = offset;
1105 
1106  silk_lsf2lpc(nlsf, lpc, order);
1107  } else {
1108  s->nlsf_interp_factor = 4;
1109  silk_lsf2lpc(nlsf, lpc, order);
1110  }
1111 
1112  memcpy(frame->nlsf, nlsf, order * sizeof(nlsf[0]));
1113  memcpy(frame->lpc, lpc, order * sizeof(lpc[0]));
1114 }
1115 
1116 static inline void silk_count_children(OpusRangeCoder *rc, int model, int32_t total,
1117  int32_t child[2])
1118 {
1119  if (total != 0) {
1120  child[0] = opus_rc_getsymbol(rc,
1121  silk_model_pulse_location[model] + (((total - 1 + 5) * (total - 1)) >> 1));
1122  child[1] = total - child[0];
1123  } else {
1124  child[0] = 0;
1125  child[1] = 0;
1126  }
1127 }
1128 
1129 static inline void silk_decode_excitation(SilkContext *s, OpusRangeCoder *rc,
1130  float* excitationf,
1131  int qoffset_high, int active, int voiced)
1132 {
1133  int i;
1134  uint32_t seed;
1135  int shellblocks;
1136  int ratelevel;
1137  uint8_t pulsecount[20]; // total pulses in each shell block
1138  uint8_t lsbcount[20] = {0}; // raw lsbits defined for each pulse in each shell block
1139  int32_t excitation[320]; // Q23
1140 
1141  /* excitation parameters */
1142  seed = opus_rc_getsymbol(rc, silk_model_lcg_seed);
1143  shellblocks = silk_shell_blocks[s->bandwidth][s->subframes >> 2];
1144  ratelevel = opus_rc_getsymbol(rc, silk_model_exc_rate[voiced]);
1145 
1146  for (i = 0; i < shellblocks; i++) {
1147  pulsecount[i] = opus_rc_getsymbol(rc, silk_model_pulse_count[ratelevel]);
1148  if (pulsecount[i] == 17) {
1149  while (pulsecount[i] == 17 && ++lsbcount[i] != 10)
1150  pulsecount[i] = opus_rc_getsymbol(rc, silk_model_pulse_count[9]);
1151  if (lsbcount[i] == 10)
1152  pulsecount[i] = opus_rc_getsymbol(rc, silk_model_pulse_count[10]);
1153  }
1154  }
1155 
1156  /* decode pulse locations using PVQ */
1157  for (i = 0; i < shellblocks; i++) {
1158  if (pulsecount[i] != 0) {
1159  int a, b, c, d;
1160  int32_t * location = excitation + 16*i;
1161  int32_t branch[4][2];
1162  branch[0][0] = pulsecount[i];
1163 
1164  /* unrolled tail recursion */
1165  for (a = 0; a < 1; a++) {
1166  silk_count_children(rc, 0, branch[0][a], branch[1]);
1167  for (b = 0; b < 2; b++) {
1168  silk_count_children(rc, 1, branch[1][b], branch[2]);
1169  for (c = 0; c < 2; c++) {
1170  silk_count_children(rc, 2, branch[2][c], branch[3]);
1171  for (d = 0; d < 2; d++) {
1172  silk_count_children(rc, 3, branch[3][d], location);
1173  location += 2;
1174  }
1175  }
1176  }
1177  }
1178  } else
1179  memset(excitation + 16*i, 0, 16*sizeof(int32_t));
1180  }
1181 
1182  /* decode least significant bits */
1183  for (i = 0; i < shellblocks << 4; i++) {
1184  int bit;
1185  for (bit = 0; bit < lsbcount[i >> 4]; bit++)
1186  excitation[i] = (excitation[i] << 1) |
1187  opus_rc_getsymbol(rc, silk_model_excitation_lsb);
1188  }
1189 
1190  /* decode signs */
1191  for (i = 0; i < shellblocks << 4; i++) {
1192  if (excitation[i] != 0) {
1193  int sign = opus_rc_getsymbol(rc, silk_model_excitation_sign[active +
1194  voiced][qoffset_high][FFMIN(pulsecount[i >> 4], 6)]);
1195  if (sign == 0)
1196  excitation[i] *= -1;
1197  }
1198  }
1199 
1200  /* assemble the excitation */
1201  for (i = 0; i < shellblocks << 4; i++) {
1202  int value = excitation[i];
1203  excitation[i] = value * 256 | silk_quant_offset[voiced][qoffset_high];
1204  if (value < 0) excitation[i] += 20;
1205  else if (value > 0) excitation[i] -= 20;
1206 
1207  /* invert samples pseudorandomly */
1208  seed = 196314165 * seed + 907633515;
1209  if (seed & 0x80000000)
1210  excitation[i] *= -1;
1211  seed += value;
1212 
1213  excitationf[i] = excitation[i] / 8388608.0f;
1214  }
1215 }
1216 
1217 /** Maximum residual history according to 4.2.7.6.1 */
1218 #define SILK_MAX_LAG (288 + LTP_ORDER / 2)
1219 
1220 /** Order of the LTP filter */
1221 #define LTP_ORDER 5
1222 
1223 static void silk_decode_frame(SilkContext *s, OpusRangeCoder *rc,
1224  int frame_num, int channel, int coded_channels, int active, int active1)
1225 {
1226  /* per frame */
1227  int voiced; // combines with active to indicate inactive, active, or active+voiced
1228  int qoffset_high;
1229  int order; // order of the LPC coefficients
1230  float lpc_leadin[16], lpc_body[16], residual[SILK_MAX_LAG + SILK_HISTORY];
1231  int has_lpc_leadin;
1232  float ltpscale;
1233 
1234  /* per subframe */
1235  struct {
1236  float gain;
1237  int pitchlag;
1238  float ltptaps[5];
1239  } sf[4];
1240 
1241  SilkFrame * const frame = s->frame + channel;
1242 
1243  int i;
1244 
1245  /* obtain stereo weights */
1246  if (coded_channels == 2 && channel == 0) {
1247  int n, wi[2], ws[2], w[2];
1248  n = opus_rc_getsymbol(rc, silk_model_stereo_s1);
1249  wi[0] = opus_rc_getsymbol(rc, silk_model_stereo_s2) + 3 * (n / 5);
1250  ws[0] = opus_rc_getsymbol(rc, silk_model_stereo_s3);
1251  wi[1] = opus_rc_getsymbol(rc, silk_model_stereo_s2) + 3 * (n % 5);
1252  ws[1] = opus_rc_getsymbol(rc, silk_model_stereo_s3);
1253 
1254  for (i = 0; i < 2; i++)
1255  w[i] = silk_stereo_weights[wi[i]] +
1256  (((silk_stereo_weights[wi[i] + 1] - silk_stereo_weights[wi[i]]) * 6554) >> 16)
1257  * (ws[i]*2 + 1);
1258 
1259  s->stereo_weights[0] = (w[0] - w[1]) / 8192.0;
1260  s->stereo_weights[1] = w[1] / 8192.0;
1261 
1262  /* and read the mid-only flag */
1263  s->midonly = active1 ? 0 : opus_rc_getsymbol(rc, silk_model_mid_only);
1264  }
1265 
1266  /* obtain frame type */
1267  if (!active) {
1268  qoffset_high = opus_rc_getsymbol(rc, silk_model_frame_type_inactive);
1269  voiced = 0;
1270  } else {
1271  int type = opus_rc_getsymbol(rc, silk_model_frame_type_active);
1272  qoffset_high = type & 1;
1273  voiced = type >> 1;
1274  }
1275 
1276  /* obtain subframe quantization gains */
1277  for (i = 0; i < s->subframes; i++) {
1278  int log_gain; //Q7
1279  int ipart, fpart, lingain;
1280 
1281  if (i == 0 && (frame_num == 0 || !frame->coded)) {
1282  /* gain is coded absolute */
1283  int x = opus_rc_getsymbol(rc, silk_model_gain_highbits[active + voiced]);
1284  log_gain = (x<<3) | opus_rc_getsymbol(rc, silk_model_gain_lowbits);
1285 
1286  if (frame->coded)
1287  log_gain = FFMAX(log_gain, frame->log_gain - 16);
1288  } else {
1289  /* gain is coded relative */
1290  int delta_gain = opus_rc_getsymbol(rc, silk_model_gain_delta);
1291  log_gain = av_clip(FFMAX((delta_gain<<1) - 16,
1292  frame->log_gain + delta_gain - 4), 0, 63);
1293  }
1294 
1295  frame->log_gain = log_gain;
1296 
1297  /* approximate 2**(x/128) with a Q7 (i.e. non-integer) input */
1298  log_gain = (log_gain * 0x1D1C71 >> 16) + 2090;
1299  ipart = log_gain >> 7;
1300  fpart = log_gain & 127;
1301  lingain = (1 << ipart) + ((-174 * fpart * (128-fpart) >>16) + fpart) * ((1<<ipart) >> 7);
1302  sf[i].gain = lingain / 65536.0f;
1303  }
1304 
1305  /* obtain LPC filter coefficients */
1306  silk_decode_lpc(s, frame, rc, lpc_leadin, lpc_body, &order, &has_lpc_leadin, voiced);
1307 
1308  /* obtain pitch lags, if this is a voiced frame */
1309  if (voiced) {
1310  int lag_absolute = (!frame_num || !frame->prev_voiced);
1311  int primarylag; // primary pitch lag for the entire SILK frame
1312  int ltpfilter;
1313  const int8_t * offsets;
1314 
1315  if (!lag_absolute) {
1316  int delta = opus_rc_getsymbol(rc, silk_model_pitch_delta);
1317  if (delta)
1318  primarylag = frame->primarylag + delta - 9;
1319  else
1320  lag_absolute = 1;
1321  }
1322 
1323  if (lag_absolute) {
1324  /* primary lag is coded absolute */
1325  int highbits, lowbits;
1326  const uint16_t *model[] = {
1327  silk_model_pitch_lowbits_nb, silk_model_pitch_lowbits_mb,
1328  silk_model_pitch_lowbits_wb
1329  };
1330  highbits = opus_rc_getsymbol(rc, silk_model_pitch_highbits);
1331  lowbits = opus_rc_getsymbol(rc, model[s->bandwidth]);
1332 
1333  primarylag = silk_pitch_min_lag[s->bandwidth] +
1334  highbits*silk_pitch_scale[s->bandwidth] + lowbits;
1335  }
1336  frame->primarylag = primarylag;
1337 
1338  if (s->subframes == 2)
1339  offsets = (s->bandwidth == OPUS_BANDWIDTH_NARROWBAND)
1340  ? silk_pitch_offset_nb10ms[opus_rc_getsymbol(rc,
1341  silk_model_pitch_contour_nb10ms)]
1342  : silk_pitch_offset_mbwb10ms[opus_rc_getsymbol(rc,
1343  silk_model_pitch_contour_mbwb10ms)];
1344  else
1345  offsets = (s->bandwidth == OPUS_BANDWIDTH_NARROWBAND)
1346  ? silk_pitch_offset_nb20ms[opus_rc_getsymbol(rc,
1347  silk_model_pitch_contour_nb20ms)]
1348  : silk_pitch_offset_mbwb20ms[opus_rc_getsymbol(rc,
1349  silk_model_pitch_contour_mbwb20ms)];
1350 
1351  for (i = 0; i < s->subframes; i++)
1352  sf[i].pitchlag = av_clip(primarylag + offsets[i],
1353  silk_pitch_min_lag[s->bandwidth],
1354  silk_pitch_max_lag[s->bandwidth]);
1355 
1356  /* obtain LTP filter coefficients */
1357  ltpfilter = opus_rc_getsymbol(rc, silk_model_ltp_filter);
1358  for (i = 0; i < s->subframes; i++) {
1359  int index, j;
1360  const uint16_t *filter_sel[] = {
1361  silk_model_ltp_filter0_sel, silk_model_ltp_filter1_sel,
1362  silk_model_ltp_filter2_sel
1363  };
1364  const int8_t (*filter_taps[])[5] = {
1365  silk_ltp_filter0_taps, silk_ltp_filter1_taps, silk_ltp_filter2_taps
1366  };
1367  index = opus_rc_getsymbol(rc, filter_sel[ltpfilter]);
1368  for (j = 0; j < 5; j++)
1369  sf[i].ltptaps[j] = filter_taps[ltpfilter][index][j] / 128.0f;
1370  }
1371  }
1372 
1373  /* obtain LTP scale factor */
1374  if (voiced && frame_num == 0)
1375  ltpscale = silk_ltp_scale_factor[opus_rc_getsymbol(rc,
1376  silk_model_ltp_scale_index)] / 16384.0f;
1377  else ltpscale = 15565.0f/16384.0f;
1378 
1379  /* generate the excitation signal for the entire frame */
1380  silk_decode_excitation(s, rc, residual + SILK_MAX_LAG, qoffset_high,
1381  active, voiced);
1382 
1383  /* skip synthesising the side channel if we want mono-only */
1384  if (s->output_channels == channel)
1385  return;
1386 
1387  /* generate the output signal */
1388  for (i = 0; i < s->subframes; i++) {
1389  const float * lpc_coeff = (i < 2 && has_lpc_leadin) ? lpc_leadin : lpc_body;
1390  float *dst = frame->output + SILK_HISTORY + i * s->sflength;
1391  float *resptr = residual + SILK_MAX_LAG + i * s->sflength;
1392  float *lpc = frame->lpc_history + SILK_HISTORY + i * s->sflength;
1393  float sum;
1394  int j, k;
1395 
1396  if (voiced) {
1397  int out_end;
1398  float scale;
1399 
1400  if (i < 2 || s->nlsf_interp_factor == 4) {
1401  out_end = -i * s->sflength;
1402  scale = ltpscale;
1403  } else {
1404  out_end = -(i - 2) * s->sflength;
1405  scale = 1.0f;
1406  }
1407 
1408  /* when the LPC coefficients change, a re-whitening filter is used */
1409  /* to produce a residual that accounts for the change */
1410  for (j = - sf[i].pitchlag - LTP_ORDER/2; j < out_end; j++) {
1411  sum = dst[j];
1412  for (k = 0; k < order; k++)
1413  sum -= lpc_coeff[k] * dst[j - k - 1];
1414  resptr[j] = av_clipf(sum, -1.0f, 1.0f) * scale / sf[i].gain;
1415  }
1416 
1417  if (out_end) {
1418  float rescale = sf[i-1].gain / sf[i].gain;
1419  for (j = out_end; j < 0; j++)
1420  resptr[j] *= rescale;
1421  }
1422 
1423  /* LTP synthesis */
1424  for (j = 0; j < s->sflength; j++) {
1425  sum = resptr[j];
1426  for (k = 0; k < LTP_ORDER; k++)
1427  sum += sf[i].ltptaps[k] * resptr[j - sf[i].pitchlag + LTP_ORDER/2 - k];
1428  resptr[j] = sum;
1429  }
1430  }
1431 
1432  /* LPC synthesis */
1433  for (j = 0; j < s->sflength; j++) {
1434  sum = resptr[j] * sf[i].gain;
1435  for (k = 1; k <= order; k++)
1436  sum += lpc_coeff[k - 1] * lpc[j - k];
1437 
1438  lpc[j] = sum;
1439  dst[j] = av_clipf(sum, -1.0f, 1.0f);
1440  }
1441  }
1442 
1443  frame->prev_voiced = voiced;
1444  memmove(frame->lpc_history, frame->lpc_history + s->flength, SILK_HISTORY * sizeof(float));
1445  memmove(frame->output, frame->output + s->flength, SILK_HISTORY * sizeof(float));
1446 
1447  frame->coded = 1;
1448 }
1449 
1450 static void silk_unmix_ms(SilkContext *s, float *l, float *r)
1451 {
1452  float *mid = s->frame[0].output + SILK_HISTORY - s->flength;
1453  float *side = s->frame[1].output + SILK_HISTORY - s->flength;
1454  float w0_prev = s->prev_stereo_weights[0];
1455  float w1_prev = s->prev_stereo_weights[1];
1456  float w0 = s->stereo_weights[0];
1457  float w1 = s->stereo_weights[1];
1458  int n1 = silk_stereo_interp_len[s->bandwidth];
1459  int i;
1460 
1461  for (i = 0; i < n1; i++) {
1462  float interp0 = w0_prev + i * (w0 - w0_prev) / n1;
1463  float interp1 = w1_prev + i * (w1 - w1_prev) / n1;
1464  float p0 = 0.25 * (mid[i - 2] + 2 * mid[i - 1] + mid[i]);
1465 
1466  l[i] = av_clipf((1 + interp1) * mid[i - 1] + side[i - 1] + interp0 * p0, -1.0, 1.0);
1467  r[i] = av_clipf((1 - interp1) * mid[i - 1] - side[i - 1] - interp0 * p0, -1.0, 1.0);
1468  }
1469 
1470  for (; i < s->flength; i++) {
1471  float p0 = 0.25 * (mid[i - 2] + 2 * mid[i - 1] + mid[i]);
1472 
1473  l[i] = av_clipf((1 + w1) * mid[i - 1] + side[i - 1] + w0 * p0, -1.0, 1.0);
1474  r[i] = av_clipf((1 - w1) * mid[i - 1] - side[i - 1] - w0 * p0, -1.0, 1.0);
1475  }
1476 
1477  memcpy(s->prev_stereo_weights, s->stereo_weights, sizeof(s->stereo_weights));
1478 }
1479 
1480 static void silk_flush_frame(SilkFrame *frame)
1481 {
1482  if (!frame->coded)
1483  return;
1484 
1485  memset(frame->output, 0, sizeof(frame->output));
1486  memset(frame->lpc_history, 0, sizeof(frame->lpc_history));
1487 
1488  memset(frame->lpc, 0, sizeof(frame->lpc));
1489  memset(frame->nlsf, 0, sizeof(frame->nlsf));
1490 
1491  frame->log_gain = 0;
1492 
1493  frame->primarylag = 0;
1494  frame->prev_voiced = 0;
1495  frame->coded = 0;
1496 }
1497 
1498 int ff_silk_decode_superframe(SilkContext *s, OpusRangeCoder *rc,
1499  float *output[2],
1500  enum OpusBandwidth bandwidth,
1501  int coded_channels,
1502  int duration_ms)
1503 {
1504  int active[2][6], redundancy[2];
1505  int nb_frames, i, j;
1506 
1507  if (bandwidth > OPUS_BANDWIDTH_WIDEBAND ||
1508  coded_channels > 2 || duration_ms > 60) {
1509  av_log(s->avctx, AV_LOG_ERROR, "Invalid parameters passed "
1510  "to the SILK decoder.\n");
1511  return AVERROR(EINVAL);
1512  }
1513 
1514  nb_frames = 1 + (duration_ms > 20) + (duration_ms > 40);
1515  s->subframes = duration_ms / nb_frames / 5; // 5ms subframes
1516  s->sflength = 20 * (bandwidth + 2);
1517  s->flength = s->sflength * s->subframes;
1518  s->bandwidth = bandwidth;
1519  s->wb = bandwidth == OPUS_BANDWIDTH_WIDEBAND;
1520 
1521  /* make sure to flush the side channel when switching from mono to stereo */
1522  if (coded_channels > s->prev_coded_channels)
1523  silk_flush_frame(&s->frame[1]);
1524  s->prev_coded_channels = coded_channels;
1525 
1526  /* read the LP-layer header bits */
1527  for (i = 0; i < coded_channels; i++) {
1528  for (j = 0; j < nb_frames; j++)
1529  active[i][j] = opus_rc_p2model(rc, 1);
1530 
1531  redundancy[i] = opus_rc_p2model(rc, 1);
1532  if (redundancy[i]) {
1533  av_log(s->avctx, AV_LOG_ERROR, "LBRR frames present; this is unsupported\n");
1534  return AVERROR_PATCHWELCOME;
1535  }
1536  }
1537 
1538  for (i = 0; i < nb_frames; i++) {
1539  for (j = 0; j < coded_channels && !s->midonly; j++)
1540  silk_decode_frame(s, rc, i, j, coded_channels, active[j][i], active[1][i]);
1541 
1542  /* reset the side channel if it is not coded */
1543  if (s->midonly && s->frame[1].coded)
1544  silk_flush_frame(&s->frame[1]);
1545 
1546  if (coded_channels == 1 || s->output_channels == 1) {
1547  for (j = 0; j < s->output_channels; j++) {
1548  memcpy(output[j] + i * s->flength,
1549  s->frame[0].output + SILK_HISTORY - s->flength - 2,
1550  s->flength * sizeof(float));
1551  }
1552  } else {
1553  silk_unmix_ms(s, output[0] + i * s->flength, output[1] + i * s->flength);
1554  }
1555 
1556  s->midonly = 0;
1557  }
1558 
1559  return nb_frames * s->flength;
1560 }
1561 
1562 void ff_silk_free(SilkContext **ps)
1563 {
1564  av_freep(ps);
1565 }
1566 
1567 void ff_silk_flush(SilkContext *s)
1568 {
1569  silk_flush_frame(&s->frame[0]);
1570  silk_flush_frame(&s->frame[1]);
1571 
1572  memset(s->prev_stereo_weights, 0, sizeof(s->prev_stereo_weights));
1573 }
1574 
1575 int ff_silk_init(AVCodecContext *avctx, SilkContext **ps, int output_channels)
1576 {
1577  SilkContext *s;
1578 
1579  if (output_channels != 1 && output_channels != 2) {
1580  av_log(avctx, AV_LOG_ERROR, "Invalid number of output channels: %d\n",
1581  output_channels);
1582  return AVERROR(EINVAL);
1583  }
1584 
1585  s = av_mallocz(sizeof(*s));
1586  if (!s)
1587  return AVERROR(ENOMEM);
1588 
1589  s->avctx = avctx;
1590  s->output_channels = output_channels;
1591 
1592  ff_silk_flush(s);
1593 
1594  *ps = s;
1595 
1596  return 0;
1597 }
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