GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/opus_silk.c Lines: 397 435 91.3 %
Date: 2021-01-21 21:11:50 Branches: 263 316 83.2 %

Line Branch Exec Source
1
/*
2
 * Copyright (c) 2012 Andrew D'Addesio
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 * 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
#include "opustab.h"
31
32
typedef struct SilkFrame {
33
    int coded;
34
    int log_gain;
35
    int16_t nlsf[16];
36
    float    lpc[16];
37
38
    float output     [2 * SILK_HISTORY];
39
    float lpc_history[2 * SILK_HISTORY];
40
    int primarylag;
41
42
    int prev_voiced;
43
} SilkFrame;
44
45
struct SilkContext {
46
    AVCodecContext *avctx;
47
    int output_channels;
48
49
    int midonly;
50
    int subframes;
51
    int sflength;
52
    int flength;
53
    int nlsf_interp_factor;
54
55
    enum OpusBandwidth bandwidth;
56
    int wb;
57
58
    SilkFrame frame[2];
59
    float prev_stereo_weights[2];
60
    float stereo_weights[2];
61
62
    int prev_coded_channels;
63
};
64
65
13313
static inline void silk_stabilize_lsf(int16_t nlsf[16], int order, const uint16_t min_delta[17])
66
{
67
    int pass, i;
68
13701
    for (pass = 0; pass < 20; pass++) {
69
13701
        int k, min_diff = 0;
70
218778
        for (i = 0; i < order+1; i++) {
71
205077
            int low  = i != 0     ? nlsf[i-1] : 0;
72
205077
            int high = i != order ? nlsf[i]   : 32768;
73
205077
            int diff = (high - low) - (min_delta[i]);
74
75
205077
            if (diff < min_diff) {
76
389
                min_diff = diff;
77
389
                k = i;
78
79
389
                if (pass == 20)
80
                    break;
81
            }
82
        }
83
13701
        if (min_diff == 0) /* no issues; stabilized */
84
13313
            return;
85
86
        /* wiggle one or two LSFs */
87
388
        if (k == 0) {
88
            /* repel away from lower bound */
89
76
            nlsf[0] = min_delta[0];
90
312
        } else if (k == order) {
91
            /* repel away from higher bound */
92
            nlsf[order-1] = 32768 - min_delta[order];
93
        } else {
94
            /* repel away from current position */
95
312
            int min_center = 0, max_center = 32768, center_val;
96
97
            /* lower extent */
98
1429
            for (i = 0; i < k; i++)
99
1117
                min_center += min_delta[i];
100
312
            min_center += min_delta[k] >> 1;
101
102
            /* upper extent */
103
3689
            for (i = order; i > k; i--)
104
3377
                max_center -= min_delta[i];
105
312
            max_center -= min_delta[k] >> 1;
106
107
            /* move apart */
108
312
            center_val = nlsf[k - 1] + nlsf[k];
109
312
            center_val = (center_val >> 1) + (center_val & 1); // rounded divide by 2
110
312
            center_val = FFMIN(max_center, FFMAX(min_center, center_val));
111
112
312
            nlsf[k - 1] = center_val - (min_delta[k] >> 1);
113
312
            nlsf[k]     = nlsf[k - 1] + min_delta[k];
114
        }
115
    }
116
117
    /* resort to the fall-back method, the standard method for LSF stabilization */
118
119
    /* sort; as the LSFs should be nearly sorted, use insertion sort */
120
    for (i = 1; i < order; i++) {
121
        int j, value = nlsf[i];
122
        for (j = i - 1; j >= 0 && nlsf[j] > value; j--)
123
            nlsf[j + 1] = nlsf[j];
124
        nlsf[j + 1] = value;
125
    }
126
127
    /* push forwards to increase distance */
128
    if (nlsf[0] < min_delta[0])
129
        nlsf[0] = min_delta[0];
130
    for (i = 1; i < order; i++)
131
        nlsf[i] = FFMAX(nlsf[i], FFMIN(nlsf[i - 1] + min_delta[i], 32767));
132
133
    /* push backwards to increase distance */
134
    if (nlsf[order-1] > 32768 - min_delta[order])
135
        nlsf[order-1] = 32768 - min_delta[order];
136
    for (i = order-2; i >= 0; i--)
137
        if (nlsf[i] > nlsf[i + 1] - min_delta[i+1])
138
            nlsf[i] = nlsf[i + 1] - min_delta[i+1];
139
140
    return;
141
}
142
143
15550
static inline int silk_is_lpc_stable(const int16_t lpc[16], int order)
144
{
145
15550
    int k, j, DC_resp = 0;
146
    int32_t lpc32[2][16];       // Q24
147
15550
    int totalinvgain = 1 << 30; // 1.0 in Q30
148
15550
    int32_t *row = lpc32[0], *prevrow;
149
150
    /* initialize the first row for the Levinson recursion */
151
231530
    for (k = 0; k < order; k++) {
152
215980
        DC_resp += lpc[k];
153
215980
        row[k] = lpc[k] * 4096;
154
    }
155
156
15550
    if (DC_resp >= 4096)
157
        return 0;
158
159
    /* check if prediction gain pushes any coefficients too far */
160
215911
    for (k = order - 1; 1; k--) {
161
        int rc;      // Q31; reflection coefficient
162
        int gaindiv; // Q30; inverse of the gain (the divisor)
163
        int gain;    // gain for this reflection coefficient
164
        int fbits;   // fractional bits used for the gain
165
        int error;   // Q29; estimate of the error of our partial estimate of 1/gaindiv
166
167
215911
        if (FFABS(row[k]) > 16773022)
168
69
            return 0;
169
170
215842
        rc      = -(row[k] * 128);
171
215842
        gaindiv = (1 << 30) - MULH(rc, rc);
172
173
215842
        totalinvgain = MULH(totalinvgain, gaindiv) << 2;
174
215842
        if (k == 0)
175
15481
            return (totalinvgain >= 107374);
176
177
        /* approximate 1.0/gaindiv */
178
200361
        fbits = opus_ilog(gaindiv);
179
200361
        gain  = ((1 << 29) - 1) / (gaindiv >> (fbits + 1 - 16)); // Q<fbits-16>
180
200361
        error = (1 << 29) - MULL(gaindiv << (15 + 16 - fbits), gain, 16);
181
200361
        gain  = ((gain << 16) + (error * gain >> 13));
182
183
        /* switch to the next row of the LPC coefficients */
184
200361
        prevrow = row;
185
200361
        row = lpc32[k & 1];
186
187
1656042
        for (j = 0; j < k; j++) {
188
1455681
            int x = av_sat_sub32(prevrow[j], ROUND_MULL(prevrow[k - j - 1], rc, 31));
189
1455681
            int64_t tmp = ROUND_MULL(x, gain, fbits);
190
191
            /* per RFC 8251 section 6, if this calculation overflows, the filter
192
               is considered unstable. */
193

1455681
            if (tmp < INT32_MIN || tmp > INT32_MAX)
194
                return 0;
195
196
1455681
            row[j] = (int32_t)tmp;
197
        }
198
    }
199
}
200
201
30702
static void silk_lsp2poly(const int32_t lsp[16], int32_t pol[16], int half_order)
202
{
203
    int i, j;
204
205
30702
    pol[0] = 65536; // 1.0 in Q16
206
30702
    pol[1] = -lsp[0];
207
208
212910
    for (i = 1; i < half_order; i++) {
209
182208
        pol[i + 1] = pol[i - 1] * 2 - ROUND_MULL(lsp[2 * i], pol[i], 16);
210
663420
        for (j = i; j > 1; j--)
211
481212
            pol[j] += pol[j - 2] - ROUND_MULL(lsp[2 * i], pol[j - 1], 16);
212
213
182208
        pol[1] -= lsp[2 * i];
214
    }
215
30702
}
216
217
15351
static void silk_lsf2lpc(const int16_t nlsf[16], float lpcf[16], int order)
218
{
219
    int i, k;
220
    int32_t lsp[16];     // Q17; 2*cos(LSF)
221
    int32_t p[9], q[9];  // Q16
222
    int32_t lpc32[16];   // Q17
223
    int16_t lpc[16];     // Q12
224
225
    /* convert the LSFs to LSPs, i.e. 2*cos(LSF) */
226
228261
    for (k = 0; k < order; k++) {
227
212910
        int index = nlsf[k] >> 8;
228
212910
        int offset = nlsf[k] & 255;
229
212910
        int k2 = (order == 10) ? ff_silk_lsf_ordering_nbmb[k] : ff_silk_lsf_ordering_wb[k];
230
231
        /* interpolate and round */
232
212910
        lsp[k2]  = ff_silk_cosine[index] * 256;
233
212910
        lsp[k2] += (ff_silk_cosine[index + 1] - ff_silk_cosine[index]) * offset;
234
212910
        lsp[k2]  = (lsp[k2] + 4) >> 3;
235
    }
236
237
15351
    silk_lsp2poly(lsp    , p, order >> 1);
238
15351
    silk_lsp2poly(lsp + 1, q, order >> 1);
239
240
    /* reconstruct A(z) */
241
121806
    for (k = 0; k < order>>1; k++) {
242
106455
        int32_t p_tmp = p[k + 1] + p[k];
243
106455
        int32_t q_tmp = q[k + 1] - q[k];
244
106455
        lpc32[k]         = -q_tmp - p_tmp;
245
106455
        lpc32[order-k-1] =  q_tmp - p_tmp;
246
    }
247
248
    /* limit the range of the LPC coefficients to each fit within an int16_t */
249
15351
    for (i = 0; i < 10; i++) {
250
        int j;
251
15351
        unsigned int maxabs = 0;
252
228261
        for (j = 0, k = 0; j < order; j++) {
253
212910
            unsigned int x = FFABS(lpc32[k]);
254
212910
            if (x > maxabs) {
255
15351
                maxabs = x; // Q17
256
15351
                k      = j;
257
            }
258
        }
259
260
15351
        maxabs = (maxabs + 16) >> 5; // convert to Q12
261
262
15351
        if (maxabs > 32767) {
263
            /* perform bandwidth expansion */
264
            unsigned int chirp, chirp_base; // Q16
265
            maxabs = FFMIN(maxabs, 163838); // anything above this overflows chirp's numerator
266
            chirp_base = chirp = 65470 - ((maxabs - 32767) << 14) / ((maxabs * (k+1)) >> 2);
267
268
            for (k = 0; k < order; k++) {
269
                lpc32[k] = ROUND_MULL(lpc32[k], chirp, 16);
270
                chirp    = (chirp_base * chirp + 32768) >> 16;
271
            }
272
15351
        } else break;
273
    }
274
275
15351
    if (i == 10) {
276
        /* time's up: just clamp */
277
        for (k = 0; k < order; k++) {
278
            int x = (lpc32[k] + 16) >> 5;
279
            lpc[k] = av_clip_int16(x);
280
            lpc32[k] = lpc[k] << 5; // shortcut mandated by the spec; drops lower 5 bits
281
        }
282
    } else {
283
228261
        for (k = 0; k < order; k++)
284
212910
            lpc[k] = (lpc32[k] + 16) >> 5;
285
    }
286
287
    /* if the prediction gain causes the LPC filter to become unstable,
288
       apply further bandwidth expansion on the Q17 coefficients */
289

15550
    for (i = 1; i <= 16 && !silk_is_lpc_stable(lpc, order); i++) {
290
        unsigned int chirp, chirp_base;
291
199
        chirp_base = chirp = 65536 - (1 << i);
292
293
3269
        for (k = 0; k < order; k++) {
294
3070
            lpc32[k] = ROUND_MULL(lpc32[k], chirp, 16);
295
3070
            lpc[k]   = (lpc32[k] + 16) >> 5;
296
3070
            chirp    = (chirp_base * chirp + 32768) >> 16;
297
        }
298
    }
299
300
228261
    for (i = 0; i < order; i++)
301
212910
        lpcf[i] = lpc[i] / 4096.0f;
302
15351
}
303
304
13313
static inline void silk_decode_lpc(SilkContext *s, SilkFrame *frame,
305
                                   OpusRangeCoder *rc,
306
                                   float lpc_leadin[16], float lpc[16],
307
                                   int *lpc_order, int *has_lpc_leadin, int voiced)
308
{
309
    int i;
310
    int order;                   // order of the LP polynomial; 10 for NB/MB and 16 for WB
311
    int8_t  lsf_i1, lsf_i2[16];  // stage-1 and stage-2 codebook indices
312
    int16_t lsf_res[16];         // residual as a Q10 value
313
    int16_t nlsf[16];            // Q15
314
315
13313
    *lpc_order = order = s->wb ? 16 : 10;
316
317
    /* obtain LSF stage-1 and stage-2 indices */
318
13313
    lsf_i1 = ff_opus_rc_dec_cdf(rc, ff_silk_model_lsf_s1[s->wb][voiced]);
319
199189
    for (i = 0; i < order; i++) {
320
185876
        int index = s->wb ? ff_silk_lsf_s2_model_sel_wb  [lsf_i1][i] :
321
45220
                            ff_silk_lsf_s2_model_sel_nbmb[lsf_i1][i];
322
185876
        lsf_i2[i] = ff_opus_rc_dec_cdf(rc, ff_silk_model_lsf_s2[index]) - 4;
323
185876
        if (lsf_i2[i] == -4)
324
460
            lsf_i2[i] -= ff_opus_rc_dec_cdf(rc, ff_silk_model_lsf_s2_ext);
325
185416
        else if (lsf_i2[i] == 4)
326
15
            lsf_i2[i] += ff_opus_rc_dec_cdf(rc, ff_silk_model_lsf_s2_ext);
327
    }
328
329
    /* reverse the backwards-prediction step */
330
199189
    for (i = order - 1; i >= 0; i--) {
331
185876
        int qstep = s->wb ? 9830 : 11796;
332
333
185876
        lsf_res[i] = lsf_i2[i] * 1024;
334
185876
        if (lsf_i2[i] < 0)      lsf_res[i] += 102;
335
141244
        else if (lsf_i2[i] > 0) lsf_res[i] -= 102;
336
185876
        lsf_res[i] = (lsf_res[i] * qstep) >> 16;
337
338
185876
        if (i + 1 < order) {
339
172563
            int weight = s->wb ? ff_silk_lsf_pred_weights_wb  [ff_silk_lsf_weight_sel_wb  [lsf_i1][i]][i] :
340
40698
                                 ff_silk_lsf_pred_weights_nbmb[ff_silk_lsf_weight_sel_nbmb[lsf_i1][i]][i];
341
172563
            lsf_res[i] += (lsf_res[i+1] * weight) >> 8;
342
        }
343
    }
344
345
    /* reconstruct the NLSF coefficients from the supplied indices */
346
199189
    for (i = 0; i < order; i++) {
347
185876
        const uint8_t * codebook = s->wb ? ff_silk_lsf_codebook_wb  [lsf_i1] :
348
45220
                                           ff_silk_lsf_codebook_nbmb[lsf_i1];
349
        int cur, prev, next, weight_sq, weight, ipart, fpart, y, value;
350
351
        /* find the weight of the residual */
352
        /* TODO: precompute */
353
185876
        cur = codebook[i];
354
185876
        prev = i ? codebook[i - 1] : 0;
355
185876
        next = i + 1 < order ? codebook[i + 1] : 256;
356
185876
        weight_sq = (1024 / (cur - prev) + 1024 / (next - cur)) << 16;
357
358
        /* approximate square-root with mandated fixed-point arithmetic */
359
185876
        ipart = opus_ilog(weight_sq);
360
185876
        fpart = (weight_sq >> (ipart-8)) & 127;
361
185876
        y = ((ipart & 1) ? 32768 : 46214) >> ((32 - ipart)>>1);
362
185876
        weight = y + ((213 * fpart * y) >> 16);
363
364
185876
        value = cur * 128 + (lsf_res[i] * 16384) / weight;
365
185876
        nlsf[i] = av_clip_uintp2(value, 15);
366
    }
367
368
    /* stabilize the NLSF coefficients */
369
13313
    silk_stabilize_lsf(nlsf, order, s->wb ? ff_silk_lsf_min_spacing_wb :
370
                                            ff_silk_lsf_min_spacing_nbmb);
371
372
    /* produce an interpolation for the first 2 subframes, */
373
    /* and then convert both sets of NLSFs to LPC coefficients */
374
13313
    *has_lpc_leadin = 0;
375
13313
    if (s->subframes == 4) {
376
7632
        int offset = ff_opus_rc_dec_cdf(rc, ff_silk_model_lsf_interpolation_offset);
377

7632
        if (offset != 4 && frame->coded) {
378
2345
            *has_lpc_leadin = 1;
379
2345
            if (offset != 0) {
380
                int16_t nlsf_leadin[16];
381
29072
                for (i = 0; i < order; i++)
382
27034
                    nlsf_leadin[i] = frame->nlsf[i] +
383
27034
                        ((nlsf[i] - frame->nlsf[i]) * offset >> 2);
384
2038
                silk_lsf2lpc(nlsf_leadin, lpc_leadin, order);
385
            } else  /* avoid re-computation for a (roughly) 1-in-4 occurrence */
386
307
                memcpy(lpc_leadin, frame->lpc, 16 * sizeof(float));
387
        } else
388
5287
            offset = 4;
389
7632
        s->nlsf_interp_factor = offset;
390
391
7632
        silk_lsf2lpc(nlsf, lpc, order);
392
    } else {
393
5681
        s->nlsf_interp_factor = 4;
394
5681
        silk_lsf2lpc(nlsf, lpc, order);
395
    }
396
397
13313
    memcpy(frame->nlsf, nlsf, order * sizeof(nlsf[0]));
398
13313
    memcpy(frame->lpc,  lpc,  order * sizeof(lpc[0]));
399
13313
}
400
401
2321325
static inline void silk_count_children(OpusRangeCoder *rc, int model, int32_t total,
402
                                       int32_t child[2])
403
{
404
2321325
    if (total != 0) {
405
2591028
        child[0] = ff_opus_rc_dec_cdf(rc,
406
1295514
                       ff_silk_model_pulse_location[model] + (((total - 1 + 5) * (total - 1)) >> 1));
407
1295514
        child[1] = total - child[0];
408
    } else {
409
1025811
        child[0] = 0;
410
1025811
        child[1] = 0;
411
    }
412
2321325
}
413
414
13313
static inline void silk_decode_excitation(SilkContext *s, OpusRangeCoder *rc,
415
                                          float* excitationf,
416
                                          int qoffset_high, int active, int voiced)
417
{
418
    int i;
419
    uint32_t seed;
420
    int shellblocks;
421
    int ratelevel;
422
    uint8_t pulsecount[20];     // total pulses in each shell block
423
13313
    uint8_t lsbcount[20] = {0}; // raw lsbits defined for each pulse in each shell block
424
    int32_t excitation[320];    // Q23
425
426
    /* excitation parameters */
427
13313
    seed = ff_opus_rc_dec_cdf(rc, ff_silk_model_lcg_seed);
428
13313
    shellblocks = ff_silk_shell_blocks[s->bandwidth][s->subframes >> 2];
429
13313
    ratelevel = ff_opus_rc_dec_cdf(rc, ff_silk_model_exc_rate[voiced]);
430
431
193075
    for (i = 0; i < shellblocks; i++) {
432
179762
        pulsecount[i] = ff_opus_rc_dec_cdf(rc, ff_silk_model_pulse_count[ratelevel]);
433
179762
        if (pulsecount[i] == 17) {
434

23498
            while (pulsecount[i] == 17 && ++lsbcount[i] != 10)
435
13191
                pulsecount[i] = ff_opus_rc_dec_cdf(rc, ff_silk_model_pulse_count[9]);
436
10307
            if (lsbcount[i] == 10)
437
                pulsecount[i] = ff_opus_rc_dec_cdf(rc, ff_silk_model_pulse_count[10]);
438
        }
439
    }
440
441
    /* decode pulse locations using PVQ */
442
193075
    for (i = 0; i < shellblocks; i++) {
443
179762
        if (pulsecount[i] != 0) {
444
            int a, b, c, d;
445
154755
            int32_t * location = excitation + 16*i;
446
            int32_t branch[4][2];
447
154755
            branch[0][0] = pulsecount[i];
448
449
            /* unrolled tail recursion */
450
309510
            for (a = 0; a < 1; a++) {
451
154755
                silk_count_children(rc, 0, branch[0][a], branch[1]);
452
464265
                for (b = 0; b < 2; b++) {
453
309510
                    silk_count_children(rc, 1, branch[1][b], branch[2]);
454
928530
                    for (c = 0; c < 2; c++) {
455
619020
                        silk_count_children(rc, 2, branch[2][c], branch[3]);
456
1857060
                        for (d = 0; d < 2; d++) {
457
1238040
                            silk_count_children(rc, 3, branch[3][d], location);
458
1238040
                            location += 2;
459
                        }
460
                    }
461
                }
462
            }
463
        } else
464
25007
            memset(excitation + 16*i, 0, 16*sizeof(int32_t));
465
    }
466
467
    /* decode least significant bits */
468
2889505
    for (i = 0; i < shellblocks << 4; i++) {
469
        int bit;
470
3087248
        for (bit = 0; bit < lsbcount[i >> 4]; bit++)
471
211056
            excitation[i] = (excitation[i] << 1) |
472
211056
                            ff_opus_rc_dec_cdf(rc, ff_silk_model_excitation_lsb);
473
    }
474
475
    /* decode signs */
476
2889505
    for (i = 0; i < shellblocks << 4; i++) {
477
2876192
        if (excitation[i] != 0) {
478
1330110
            int sign = ff_opus_rc_dec_cdf(rc, ff_silk_model_excitation_sign[active +
479
665055
                                         voiced][qoffset_high][FFMIN(pulsecount[i >> 4], 6)]);
480
665055
            if (sign == 0)
481
442184
                excitation[i] *= -1;
482
        }
483
    }
484
485
    /* assemble the excitation */
486
2889505
    for (i = 0; i < shellblocks << 4; i++) {
487
2876192
        int value = excitation[i];
488
2876192
        excitation[i] = value * 256 | ff_silk_quant_offset[voiced][qoffset_high];
489
2876192
        if (value < 0)      excitation[i] += 20;
490
2434008
        else if (value > 0) excitation[i] -= 20;
491
492
        /* invert samples pseudorandomly */
493
2876192
        seed = 196314165 * seed + 907633515;
494
2876192
        if (seed & 0x80000000)
495
1423315
            excitation[i] *= -1;
496
2876192
        seed += value;
497
498
2876192
        excitationf[i] = excitation[i] / 8388608.0f;
499
    }
500
13313
}
501
502
/** Maximum residual history according to 4.2.7.6.1 */
503
#define SILK_MAX_LAG  (288 + LTP_ORDER / 2)
504
505
/** Order of the LTP filter */
506
#define LTP_ORDER 5
507
508
13313
static void silk_decode_frame(SilkContext *s, OpusRangeCoder *rc,
509
                              int frame_num, int channel, int coded_channels,
510
                              int active, int active1, int redundant)
511
{
512
    /* per frame */
513
    int voiced;       // combines with active to indicate inactive, active, or active+voiced
514
    int qoffset_high;
515
    int order;                             // order of the LPC coefficients
516
    float lpc_leadin[16], lpc_body[16], residual[SILK_MAX_LAG + SILK_HISTORY];
517
    int has_lpc_leadin;
518
    float ltpscale;
519
520
    /* per subframe */
521
    struct {
522
        float gain;
523
        int pitchlag;
524
        float ltptaps[5];
525
    } sf[4];
526
527
13313
    SilkFrame * const frame = s->frame + channel;
528
529
    int i;
530
531
    /* obtain stereo weights */
532

13313
    if (coded_channels == 2 && channel == 0) {
533
        int n, wi[2], ws[2], w[2];
534
4594
        n     = ff_opus_rc_dec_cdf(rc, ff_silk_model_stereo_s1);
535
4594
        wi[0] = ff_opus_rc_dec_cdf(rc, ff_silk_model_stereo_s2) + 3 * (n / 5);
536
4594
        ws[0] = ff_opus_rc_dec_cdf(rc, ff_silk_model_stereo_s3);
537
4594
        wi[1] = ff_opus_rc_dec_cdf(rc, ff_silk_model_stereo_s2) + 3 * (n % 5);
538
4594
        ws[1] = ff_opus_rc_dec_cdf(rc, ff_silk_model_stereo_s3);
539
540
13782
        for (i = 0; i < 2; i++)
541
9188
            w[i] = ff_silk_stereo_weights[wi[i]] +
542
9188
                   (((ff_silk_stereo_weights[wi[i] + 1] - ff_silk_stereo_weights[wi[i]]) * 6554) >> 16)
543
9188
                    * (ws[i]*2 + 1);
544
545
4594
        s->stereo_weights[0] = (w[0] - w[1]) / 8192.0;
546
4594
        s->stereo_weights[1] = w[1]          / 8192.0;
547
548
        /* and read the mid-only flag */
549
4594
        s->midonly = active1 ? 0 : ff_opus_rc_dec_cdf(rc, ff_silk_model_mid_only);
550
    }
551
552
    /* obtain frame type */
553
13313
    if (!active) {
554
3452
        qoffset_high = ff_opus_rc_dec_cdf(rc, ff_silk_model_frame_type_inactive);
555
3452
        voiced = 0;
556
    } else {
557
9861
        int type = ff_opus_rc_dec_cdf(rc, ff_silk_model_frame_type_active);
558
9861
        qoffset_high = type & 1;
559
9861
        voiced = type >> 1;
560
    }
561
562
    /* obtain subframe quantization gains */
563
55203
    for (i = 0; i < s->subframes; i++) {
564
        int log_gain;     //Q7
565
        int ipart, fpart, lingain;
566
567

53583
        if (i == 0 && (frame_num == 0 || !frame->coded)) {
568
            /* gain is coded absolute */
569
11693
            int x = ff_opus_rc_dec_cdf(rc, ff_silk_model_gain_highbits[active + voiced]);
570
11693
            log_gain = (x<<3) | ff_opus_rc_dec_cdf(rc, ff_silk_model_gain_lowbits);
571
572
11693
            if (frame->coded)
573
11642
                log_gain = FFMAX(log_gain, frame->log_gain - 16);
574
        } else {
575
            /* gain is coded relative */
576
30197
            int delta_gain = ff_opus_rc_dec_cdf(rc, ff_silk_model_gain_delta);
577
30197
            log_gain = av_clip_uintp2(FFMAX((delta_gain<<1) - 16,
578
                                     frame->log_gain + delta_gain - 4), 6);
579
        }
580
581
41890
        frame->log_gain = log_gain;
582
583
        /* approximate 2**(x/128) with a Q7 (i.e. non-integer) input */
584
41890
        log_gain = (log_gain * 0x1D1C71 >> 16) + 2090;
585
41890
        ipart = log_gain >> 7;
586
41890
        fpart = log_gain & 127;
587
41890
        lingain = (1 << ipart) + ((-174 * fpart * (128-fpart) >>16) + fpart) * ((1<<ipart) >> 7);
588
41890
        sf[i].gain = lingain / 65536.0f;
589
    }
590
591
    /* obtain LPC filter coefficients */
592
13313
    silk_decode_lpc(s, frame, rc, lpc_leadin, lpc_body, &order, &has_lpc_leadin, voiced);
593
594
    /* obtain pitch lags, if this is a voiced frame */
595
13313
    if (voiced) {
596

4622
        int lag_absolute = (!frame_num || !frame->prev_voiced);
597
        int primarylag;         // primary pitch lag for the entire SILK frame
598
        int ltpfilter;
599
        const int8_t * offsets;
600
601
4622
        if (!lag_absolute) {
602
609
            int delta = ff_opus_rc_dec_cdf(rc, ff_silk_model_pitch_delta);
603
609
            if (delta)
604
538
                primarylag = frame->primarylag + delta - 9;
605
            else
606
71
                lag_absolute = 1;
607
        }
608
609
4622
        if (lag_absolute) {
610
            /* primary lag is coded absolute */
611
            int highbits, lowbits;
612
            static const uint16_t * const model[] = {
613
                ff_silk_model_pitch_lowbits_nb, ff_silk_model_pitch_lowbits_mb,
614
                ff_silk_model_pitch_lowbits_wb
615
            };
616
4084
            highbits = ff_opus_rc_dec_cdf(rc, ff_silk_model_pitch_highbits);
617
4084
            lowbits  = ff_opus_rc_dec_cdf(rc, model[s->bandwidth]);
618
619
4084
            primarylag = ff_silk_pitch_min_lag[s->bandwidth] +
620
4084
                         highbits*ff_silk_pitch_scale[s->bandwidth] + lowbits;
621
        }
622
4622
        frame->primarylag = primarylag;
623
624
4622
        if (s->subframes == 2)
625
1524
            offsets = (s->bandwidth == OPUS_BANDWIDTH_NARROWBAND)
626
239
                     ? ff_silk_pitch_offset_nb10ms[ff_opus_rc_dec_cdf(rc,
627
                                                ff_silk_model_pitch_contour_nb10ms)]
628
1763
                     : ff_silk_pitch_offset_mbwb10ms[ff_opus_rc_dec_cdf(rc,
629
                                                ff_silk_model_pitch_contour_mbwb10ms)];
630
        else
631
3098
            offsets = (s->bandwidth == OPUS_BANDWIDTH_NARROWBAND)
632
807
                     ? ff_silk_pitch_offset_nb20ms[ff_opus_rc_dec_cdf(rc,
633
                                                ff_silk_model_pitch_contour_nb20ms)]
634
3905
                     : ff_silk_pitch_offset_mbwb20ms[ff_opus_rc_dec_cdf(rc,
635
                                                ff_silk_model_pitch_contour_mbwb20ms)];
636
637
20062
        for (i = 0; i < s->subframes; i++)
638
15440
            sf[i].pitchlag = av_clip(primarylag + offsets[i],
639
15440
                                     ff_silk_pitch_min_lag[s->bandwidth],
640
15440
                                     ff_silk_pitch_max_lag[s->bandwidth]);
641
642
        /* obtain LTP filter coefficients */
643
4622
        ltpfilter = ff_opus_rc_dec_cdf(rc, ff_silk_model_ltp_filter);
644
20062
        for (i = 0; i < s->subframes; i++) {
645
            int index, j;
646
            static const uint16_t * const filter_sel[] = {
647
                ff_silk_model_ltp_filter0_sel, ff_silk_model_ltp_filter1_sel,
648
                ff_silk_model_ltp_filter2_sel
649
            };
650
            static const int8_t (* const filter_taps[])[5] = {
651
                ff_silk_ltp_filter0_taps, ff_silk_ltp_filter1_taps, ff_silk_ltp_filter2_taps
652
            };
653
15440
            index = ff_opus_rc_dec_cdf(rc, filter_sel[ltpfilter]);
654
92640
            for (j = 0; j < 5; j++)
655
77200
                sf[i].ltptaps[j] = filter_taps[ltpfilter][index][j] / 128.0f;
656
        }
657
    }
658
659
    /* obtain LTP scale factor */
660

13313
    if (voiced && frame_num == 0)
661
3926
        ltpscale = ff_silk_ltp_scale_factor[ff_opus_rc_dec_cdf(rc,
662
3926
                                         ff_silk_model_ltp_scale_index)] / 16384.0f;
663
9387
    else ltpscale = 15565.0f/16384.0f;
664
665
    /* generate the excitation signal for the entire frame */
666
13313
    silk_decode_excitation(s, rc, residual + SILK_MAX_LAG, qoffset_high,
667
                           active, voiced);
668
669
    /* skip synthesising the output if we do not need it */
670
    // TODO: implement error recovery
671

13313
    if (s->output_channels == channel || redundant)
672
        return;
673
674
    /* generate the output signal */
675
55203
    for (i = 0; i < s->subframes; i++) {
676

41890
        const float * lpc_coeff = (i < 2 && has_lpc_leadin) ? lpc_leadin : lpc_body;
677
41890
        float *dst    = frame->output      + SILK_HISTORY + i * s->sflength;
678
41890
        float *resptr = residual           + SILK_MAX_LAG + i * s->sflength;
679
41890
        float *lpc    = frame->lpc_history + SILK_HISTORY + i * s->sflength;
680
        float sum;
681
        int j, k;
682
683
41890
        if (voiced) {
684
            int out_end;
685
            float scale;
686
687

15440
            if (i < 2 || s->nlsf_interp_factor == 4) {
688
13554
                out_end = -i * s->sflength;
689
13554
                scale   = ltpscale;
690
            } else {
691
1886
                out_end = -(i - 2) * s->sflength;
692
1886
                scale   = 1.0f;
693
            }
694
695
            /* when the LPC coefficients change, a re-whitening filter is used */
696
            /* to produce a residual that accounts for the change */
697
666703
            for (j = - sf[i].pitchlag - LTP_ORDER/2; j < out_end; j++) {
698
651263
                sum = dst[j];
699
9876529
                for (k = 0; k < order; k++)
700
9225266
                    sum -= lpc_coeff[k] * dst[j - k - 1];
701
651263
                resptr[j] = av_clipf(sum, -1.0f, 1.0f) * scale / sf[i].gain;
702
            }
703
704
15440
            if (out_end) {
705
9875
                float rescale = sf[i-1].gain / sf[i].gain;
706
1094295
                for (j = out_end; j < 0; j++)
707
1084420
                    resptr[j] *= rescale;
708
            }
709
710
            /* LTP synthesis */
711
1044440
            for (j = 0; j < s->sflength; j++) {
712
1029000
                sum = resptr[j];
713
6174000
                for (k = 0; k < LTP_ORDER; k++)
714
5145000
                    sum += sf[i].ltptaps[k] * resptr[j - sf[i].pitchlag + LTP_ORDER/2 - k];
715
1029000
                resptr[j] = sum;
716
            }
717
        }
718
719
        /* LPC synthesis */
720
2913090
        for (j = 0; j < s->sflength; j++) {
721
2871200
            sum = resptr[j] * sf[i].gain;
722
44256160
            for (k = 1; k <= order; k++)
723
41384960
                sum += lpc_coeff[k - 1] * lpc[j - k];
724
725
2871200
            lpc[j] = sum;
726
2871200
            dst[j] = av_clipf(sum, -1.0f, 1.0f);
727
        }
728
    }
729
730
13313
    frame->prev_voiced = voiced;
731
13313
    memmove(frame->lpc_history, frame->lpc_history + s->flength, SILK_HISTORY * sizeof(float));
732
13313
    memmove(frame->output,      frame->output      + s->flength, SILK_HISTORY * sizeof(float));
733
734
13313
    frame->coded = 1;
735
}
736
737
4594
static void silk_unmix_ms(SilkContext *s, float *l, float *r)
738
{
739
4594
    float *mid    = s->frame[0].output + SILK_HISTORY - s->flength;
740
4594
    float *side   = s->frame[1].output + SILK_HISTORY - s->flength;
741
4594
    float w0_prev = s->prev_stereo_weights[0];
742
4594
    float w1_prev = s->prev_stereo_weights[1];
743
4594
    float w0      = s->stereo_weights[0];
744
4594
    float w1      = s->stereo_weights[1];
745
4594
    int n1        = ff_silk_stereo_interp_len[s->bandwidth];
746
    int i;
747
748
522066
    for (i = 0; i < n1; i++) {
749
517472
        float interp0 = w0_prev + i * (w0 - w0_prev) / n1;
750
517472
        float interp1 = w1_prev + i * (w1 - w1_prev) / n1;
751
517472
        float p0      = 0.25 * (mid[i - 2] + 2 * mid[i - 1] + mid[i]);
752
753
517472
        l[i] = av_clipf((1 + interp1) * mid[i - 1] + side[i - 1] + interp0 * p0, -1.0, 1.0);
754
517472
        r[i] = av_clipf((1 - interp1) * mid[i - 1] - side[i - 1] - interp0 * p0, -1.0, 1.0);
755
    }
756
757
427642
    for (; i < s->flength; i++) {
758
423048
        float p0 = 0.25 * (mid[i - 2] + 2 * mid[i - 1] + mid[i]);
759
760
423048
        l[i] = av_clipf((1 + w1) * mid[i - 1] + side[i - 1] + w0 * p0, -1.0, 1.0);
761
423048
        r[i] = av_clipf((1 - w1) * mid[i - 1] - side[i - 1] - w0 * p0, -1.0, 1.0);
762
    }
763
764
4594
    memcpy(s->prev_stereo_weights, s->stereo_weights, sizeof(s->stereo_weights));
765
4594
}
766
767
49973
static void silk_flush_frame(SilkFrame *frame)
768
{
769
49973
    if (!frame->coded)
770
49940
        return;
771
772
33
    memset(frame->output,      0, sizeof(frame->output));
773
33
    memset(frame->lpc_history, 0, sizeof(frame->lpc_history));
774
775
33
    memset(frame->lpc,  0, sizeof(frame->lpc));
776
33
    memset(frame->nlsf, 0, sizeof(frame->nlsf));
777
778
33
    frame->log_gain = 0;
779
780
33
    frame->primarylag  = 0;
781
33
    frame->prev_voiced = 0;
782
33
    frame->coded       = 0;
783
}
784
785
9471
int ff_silk_decode_superframe(SilkContext *s, OpusRangeCoder *rc,
786
                              float *output[2],
787
                              enum OpusBandwidth bandwidth,
788
                              int coded_channels,
789
                              int duration_ms)
790
{
791
    int active[2][6], redundancy[2];
792
    int nb_frames, i, j;
793
794

9471
    if (bandwidth > OPUS_BANDWIDTH_WIDEBAND ||
795
9471
        coded_channels > 2 || duration_ms > 60) {
796
        av_log(s->avctx, AV_LOG_ERROR, "Invalid parameters passed "
797
               "to the SILK decoder.\n");
798
        return AVERROR(EINVAL);
799
    }
800
801
9471
    nb_frames = 1 + (duration_ms > 20) + (duration_ms > 40);
802
9471
    s->subframes = duration_ms / nb_frames / 5;         // 5ms subframes
803
9471
    s->sflength  = 20 * (bandwidth + 2);
804
9471
    s->flength   = s->sflength * s->subframes;
805
9471
    s->bandwidth = bandwidth;
806
9471
    s->wb        = bandwidth == OPUS_BANDWIDTH_WIDEBAND;
807
808
    /* make sure to flush the side channel when switching from mono to stereo */
809
9471
    if (coded_channels > s->prev_coded_channels)
810
34
        silk_flush_frame(&s->frame[1]);
811
9471
    s->prev_coded_channels = coded_channels;
812
813
    /* read the LP-layer header bits */
814
22998
    for (i = 0; i < coded_channels; i++) {
815
28674
        for (j = 0; j < nb_frames; j++)
816
15147
            active[i][j] = ff_opus_rc_dec_log(rc, 1);
817
818
13527
        redundancy[i] = ff_opus_rc_dec_log(rc, 1);
819
    }
820
821
    /* read the per-frame LBRR flags */
822
22998
    for (i = 0; i < coded_channels; i++)
823

13527
        if (redundancy[i] && duration_ms > 20) {
824
            redundancy[i] = ff_opus_rc_dec_cdf(rc, duration_ms == 40 ?
825
                                                   ff_silk_model_lbrr_flags_40 : ff_silk_model_lbrr_flags_60);
826
        }
827
828
    /* decode the LBRR frames */
829
20024
    for (i = 0; i < nb_frames; i++) {
830
25700
        for (j = 0; j < coded_channels; j++)
831
15147
            if (redundancy[j] & (1 << i)) {
832
                int active1 = (j == 0 && !(redundancy[1] & (1 << i))) ? 0 : 1;
833
                silk_decode_frame(s, rc, i, j, coded_channels, 1, active1, 1);
834
            }
835
    }
836
837
20024
    for (i = 0; i < nb_frames; i++) {
838

23866
        for (j = 0; j < coded_channels && !s->midonly; j++)
839
13313
            silk_decode_frame(s, rc, i, j, coded_channels, active[j][i], active[1][i], 0);
840
841
        /* reset the side channel if it is not coded */
842

10553
        if (s->midonly && s->frame[1].coded)
843
13
            silk_flush_frame(&s->frame[1]);
844
845

10553
        if (coded_channels == 1 || s->output_channels == 1) {
846
17876
            for (j = 0; j < s->output_channels; j++) {
847
11917
                memcpy(output[j] + i * s->flength,
848
11917
                       s->frame[0].output + SILK_HISTORY - s->flength - 2,
849
11917
                       s->flength * sizeof(float));
850
            }
851
        } else {
852
4594
            silk_unmix_ms(s, output[0] + i * s->flength, output[1] + i * s->flength);
853
        }
854
855
10553
        s->midonly        = 0;
856
    }
857
858
9471
    return nb_frames * s->flength;
859
}
860
861
41
void ff_silk_free(SilkContext **ps)
862
{
863
41
    av_freep(ps);
864
41
}
865
866
24963
void ff_silk_flush(SilkContext *s)
867
{
868
24963
    silk_flush_frame(&s->frame[0]);
869
24963
    silk_flush_frame(&s->frame[1]);
870
871
24963
    memset(s->prev_stereo_weights, 0, sizeof(s->prev_stereo_weights));
872
24963
}
873
874
41
int ff_silk_init(AVCodecContext *avctx, SilkContext **ps, int output_channels)
875
{
876
    SilkContext *s;
877
878

41
    if (output_channels != 1 && output_channels != 2) {
879
        av_log(avctx, AV_LOG_ERROR, "Invalid number of output channels: %d\n",
880
               output_channels);
881
        return AVERROR(EINVAL);
882
    }
883
884
41
    s = av_mallocz(sizeof(*s));
885
41
    if (!s)
886
        return AVERROR(ENOMEM);
887
888
41
    s->avctx           = avctx;
889
41
    s->output_channels = output_channels;
890
891
41
    ff_silk_flush(s);
892
893
41
    *ps = s;
894
895
41
    return 0;
896
}