GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/evrcdec.c Lines: 0 432 0.0 %
Date: 2019-11-22 03:34:36 Branches: 0 252 0.0 %

Line Branch Exec Source
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/*
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 * Enhanced Variable Rate Codec, Service Option 3 decoder
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 * Copyright (c) 2013 Paul B Mahol
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21
22
/**
23
 * @file
24
 * Enhanced Variable Rate Codec, Service Option 3 decoder
25
 * @author Paul B Mahol
26
 */
27
28
#include "libavutil/mathematics.h"
29
#include "libavutil/opt.h"
30
#include "avcodec.h"
31
#include "internal.h"
32
#include "get_bits.h"
33
#include "evrcdata.h"
34
#include "acelp_vectors.h"
35
#include "lsp.h"
36
37
#define MIN_LSP_SEP (0.05 / (2.0 * M_PI))
38
#define MIN_DELAY      20
39
#define MAX_DELAY     120
40
#define NB_SUBFRAMES    3
41
#define SUBFRAME_SIZE  54
42
#define FILTER_ORDER   10
43
#define ACB_SIZE      128
44
45
typedef enum {
46
    RATE_ERRS = -1,
47
    SILENCE,
48
    RATE_QUANT,
49
    RATE_QUARTER,
50
    RATE_HALF,
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    RATE_FULL,
52
} evrc_packet_rate;
53
54
/**
55
 * EVRC-A unpacked data frame
56
 */
57
typedef struct EVRCAFrame {
58
    uint8_t  lpc_flag;        ///< spectral change indicator
59
    uint16_t lsp[4];          ///< index into LSP codebook
60
    uint8_t  pitch_delay;     ///< pitch delay for entire frame
61
    uint8_t  delay_diff;      ///< delay difference for entire frame
62
    uint8_t  acb_gain[3];     ///< adaptive codebook gain
63
    uint16_t fcb_shape[3][4]; ///< fixed codebook shape
64
    uint8_t  fcb_gain[3];     ///< fixed codebook gain index
65
    uint8_t  energy_gain;     ///< frame energy gain index
66
    uint8_t  tty;             ///< tty baud rate bit
67
} EVRCAFrame;
68
69
typedef struct EVRCContext {
70
    AVClass *class;
71
72
    int              postfilter;
73
74
    GetBitContext    gb;
75
    evrc_packet_rate bitrate;
76
    evrc_packet_rate last_valid_bitrate;
77
    EVRCAFrame       frame;
78
79
    float            lspf[FILTER_ORDER];
80
    float            prev_lspf[FILTER_ORDER];
81
    float            synthesis[FILTER_ORDER];
82
    float            postfilter_fir[FILTER_ORDER];
83
    float            postfilter_iir[FILTER_ORDER];
84
    float            postfilter_residual[ACB_SIZE + SUBFRAME_SIZE];
85
    float            pitch_delay;
86
    float            prev_pitch_delay;
87
    float            avg_acb_gain;  ///< average adaptive codebook gain
88
    float            avg_fcb_gain;  ///< average fixed codebook gain
89
    float            pitch[ACB_SIZE + FILTER_ORDER + SUBFRAME_SIZE];
90
    float            pitch_back[ACB_SIZE];
91
    float            interpolation_coeffs[136];
92
    float            energy_vector[NB_SUBFRAMES];
93
    float            fade_scale;
94
    float            last;
95
96
    uint8_t          prev_energy_gain;
97
    uint8_t          prev_error_flag;
98
    uint8_t          warned_buf_mismatch_bitrate;
99
} EVRCContext;
100
101
/**
102
 * Frame unpacking for RATE_FULL, RATE_HALF and RATE_QUANT
103
 *
104
 * @param e the context
105
 *
106
 * TIA/IS-127 Table 4.21-1
107
 */
108
static void unpack_frame(EVRCContext *e)
109
{
110
    EVRCAFrame *frame = &e->frame;
111
    GetBitContext *gb = &e->gb;
112
113
    switch (e->bitrate) {
114
    case RATE_FULL:
115
        frame->lpc_flag        = get_bits1(gb);
116
        frame->lsp[0]          = get_bits(gb,  6);
117
        frame->lsp[1]          = get_bits(gb,  6);
118
        frame->lsp[2]          = get_bits(gb,  9);
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        frame->lsp[3]          = get_bits(gb,  7);
120
        frame->pitch_delay     = get_bits(gb,  7);
121
        frame->delay_diff      = get_bits(gb,  5);
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        frame->acb_gain[0]     = get_bits(gb,  3);
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        frame->fcb_shape[0][0] = get_bits(gb,  8);
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        frame->fcb_shape[0][1] = get_bits(gb,  8);
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        frame->fcb_shape[0][2] = get_bits(gb,  8);
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        frame->fcb_shape[0][3] = get_bits(gb, 11);
127
        frame->fcb_gain[0]     = get_bits(gb,  5);
128
        frame->acb_gain[1]     = get_bits(gb,  3);
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        frame->fcb_shape[1][0] = get_bits(gb,  8);
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        frame->fcb_shape[1][1] = get_bits(gb,  8);
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        frame->fcb_shape[1][2] = get_bits(gb,  8);
132
        frame->fcb_shape[1][3] = get_bits(gb, 11);
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        frame->fcb_gain    [1] = get_bits(gb,  5);
134
        frame->acb_gain    [2] = get_bits(gb,  3);
135
        frame->fcb_shape[2][0] = get_bits(gb,  8);
136
        frame->fcb_shape[2][1] = get_bits(gb,  8);
137
        frame->fcb_shape[2][2] = get_bits(gb,  8);
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        frame->fcb_shape[2][3] = get_bits(gb, 11);
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        frame->fcb_gain    [2] = get_bits(gb,  5);
140
        frame->tty             = get_bits1(gb);
141
        break;
142
    case RATE_HALF:
143
        frame->lsp         [0] = get_bits(gb,  7);
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        frame->lsp         [1] = get_bits(gb,  7);
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        frame->lsp         [2] = get_bits(gb,  8);
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        frame->pitch_delay     = get_bits(gb,  7);
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        frame->acb_gain    [0] = get_bits(gb,  3);
148
        frame->fcb_shape[0][0] = get_bits(gb, 10);
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        frame->fcb_gain    [0] = get_bits(gb,  4);
150
        frame->acb_gain    [1] = get_bits(gb,  3);
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        frame->fcb_shape[1][0] = get_bits(gb, 10);
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        frame->fcb_gain    [1] = get_bits(gb,  4);
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        frame->acb_gain    [2] = get_bits(gb,  3);
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        frame->fcb_shape[2][0] = get_bits(gb, 10);
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        frame->fcb_gain    [2] = get_bits(gb,  4);
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        break;
157
    case RATE_QUANT:
158
        frame->lsp         [0] = get_bits(gb, 4);
159
        frame->lsp         [1] = get_bits(gb, 4);
160
        frame->energy_gain     = get_bits(gb, 8);
161
        break;
162
    }
163
}
164
165
static evrc_packet_rate buf_size2bitrate(const int buf_size)
166
{
167
    switch (buf_size) {
168
    case 23: return RATE_FULL;
169
    case 11: return RATE_HALF;
170
    case  6: return RATE_QUARTER;
171
    case  3: return RATE_QUANT;
172
    case  1: return SILENCE;
173
    }
174
175
    return RATE_ERRS;
176
}
177
178
/**
179
 * Determine the bitrate from the frame size and/or the first byte of the frame.
180
 *
181
 * @param avctx the AV codec context
182
 * @param buf_size length of the buffer
183
 * @param buf the bufffer
184
 *
185
 * @return the bitrate on success,
186
 *         RATE_ERRS  if the bitrate cannot be satisfactorily determined
187
 */
188
static evrc_packet_rate determine_bitrate(AVCodecContext *avctx,
189
                                          int *buf_size,
190
                                          const uint8_t **buf)
191
{
192
    evrc_packet_rate bitrate;
193
194
    if ((bitrate = buf_size2bitrate(*buf_size)) >= 0) {
195
        if (bitrate > **buf) {
196
            EVRCContext *e = avctx->priv_data;
197
            if (!e->warned_buf_mismatch_bitrate) {
198
                av_log(avctx, AV_LOG_WARNING,
199
                       "Claimed bitrate and buffer size mismatch.\n");
200
                e->warned_buf_mismatch_bitrate = 1;
201
            }
202
            bitrate = **buf;
203
        } else if (bitrate < **buf) {
204
            av_log(avctx, AV_LOG_ERROR,
205
                   "Buffer is too small for the claimed bitrate.\n");
206
            return RATE_ERRS;
207
        }
208
        (*buf)++;
209
        *buf_size -= 1;
210
    } else if ((bitrate = buf_size2bitrate(*buf_size + 1)) >= 0) {
211
        av_log(avctx, AV_LOG_DEBUG,
212
               "Bitrate byte is missing, guessing the bitrate from packet size.\n");
213
    } else
214
        return RATE_ERRS;
215
216
    return bitrate;
217
}
218
219
static void warn_insufficient_frame_quality(AVCodecContext *avctx,
220
                                            const char *message)
221
{
222
    av_log(avctx, AV_LOG_WARNING, "Frame #%d, %s\n",
223
           avctx->frame_number, message);
224
}
225
226
/**
227
 * Initialize the speech codec according to the specification.
228
 *
229
 * TIA/IS-127 5.2
230
 */
231
static av_cold int evrc_decode_init(AVCodecContext *avctx)
232
{
233
    EVRCContext *e = avctx->priv_data;
234
    int i, n, idx = 0;
235
    float denom = 2.0 / (2.0 * 8.0 + 1.0);
236
237
    avctx->channels       = 1;
238
    avctx->channel_layout = AV_CH_LAYOUT_MONO;
239
    avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;
240
241
    for (i = 0; i < FILTER_ORDER; i++) {
242
        e->prev_lspf[i] = (i + 1) * 0.048;
243
        e->synthesis[i] = 0.0;
244
    }
245
246
    for (i = 0; i < ACB_SIZE; i++)
247
        e->pitch[i] = e->pitch_back[i] = 0.0;
248
249
    e->last_valid_bitrate = RATE_QUANT;
250
    e->prev_pitch_delay   = 40.0;
251
    e->fade_scale         = 1.0;
252
    e->prev_error_flag    = 0;
253
    e->avg_acb_gain = e->avg_fcb_gain = 0.0;
254
255
    for (i = 0; i < 8; i++) {
256
        float tt = ((float)i - 8.0 / 2.0) / 8.0;
257
258
        for (n = -8; n <= 8; n++, idx++) {
259
            float arg1 = M_PI * 0.9 * (tt - n);
260
            float arg2 = M_PI * (tt - n);
261
262
            e->interpolation_coeffs[idx] = 0.9;
263
            if (arg1)
264
                e->interpolation_coeffs[idx] *= (0.54 + 0.46 * cos(arg2 * denom)) *
265
                                                 sin(arg1) / arg1;
266
        }
267
    }
268
269
    return 0;
270
}
271
272
/**
273
 * Decode the 10 vector quantized line spectral pair frequencies from the LSP
274
 * transmission codes of any bitrate and check for badly received packets.
275
 *
276
 * @param e the context
277
 *
278
 * @return 0 on success, -1 if the packet is badly received
279
 *
280
 * TIA/IS-127 5.2.1, 5.7.1
281
 */
282
static int decode_lspf(EVRCContext *e)
283
{
284
    const float * const *codebooks = evrc_lspq_codebooks[e->bitrate];
285
    int i, j, k = 0;
286
287
    for (i = 0; i < evrc_lspq_nb_codebooks[e->bitrate]; i++) {
288
        int row_size = evrc_lspq_codebooks_row_sizes[e->bitrate][i];
289
        const float *codebook = codebooks[i];
290
291
        for (j = 0; j < row_size; j++)
292
            e->lspf[k++] = codebook[e->frame.lsp[i] * row_size + j];
293
    }
294
295
    // check for monotonic LSPs
296
    for (i = 1; i < FILTER_ORDER; i++)
297
        if (e->lspf[i] <= e->lspf[i - 1])
298
            return -1;
299
300
    // check for minimum separation of LSPs at the splits
301
    for (i = 0, k = 0; i < evrc_lspq_nb_codebooks[e->bitrate] - 1; i++) {
302
        k += evrc_lspq_codebooks_row_sizes[e->bitrate][i];
303
        if (e->lspf[k] - e->lspf[k - 1] <= MIN_LSP_SEP)
304
            return -1;
305
    }
306
307
    return 0;
308
}
309
310
/*
311
 * Interpolation of LSP parameters.
312
 *
313
 * TIA/IS-127 5.2.3.1, 5.7.3.2
314
 */
315
static void interpolate_lsp(float *ilsp, const float *lsp,
316
                            const float *prev, int index)
317
{
318
    static const float lsp_interpolation_factors[] = { 0.1667, 0.5, 0.8333 };
319
    ff_weighted_vector_sumf(ilsp, prev, lsp,
320
                            1.0 - lsp_interpolation_factors[index],
321
                            lsp_interpolation_factors[index], FILTER_ORDER);
322
}
323
324
/*
325
 * Reconstruction of the delay contour.
326
 *
327
 * TIA/IS-127 5.2.2.3.2
328
 */
329
static void interpolate_delay(float *dst, float current, float prev, int index)
330
{
331
    static const float d_interpolation_factors[] = { 0, 0.3313, 0.6625, 1, 1 };
332
    dst[0] = (1.0 - d_interpolation_factors[index    ]) * prev
333
                  + d_interpolation_factors[index    ]  * current;
334
    dst[1] = (1.0 - d_interpolation_factors[index + 1]) * prev
335
                  + d_interpolation_factors[index + 1]  * current;
336
    dst[2] = (1.0 - d_interpolation_factors[index + 2]) * prev
337
                  + d_interpolation_factors[index + 2]  * current;
338
}
339
340
/*
341
 * Convert the quantized, interpolated line spectral frequencies,
342
 * to prediction coefficients.
343
 *
344
 * TIA/IS-127 5.2.3.2, 4.7.2.2
345
 */
346
static void decode_predictor_coeffs(const float *ilspf, float *ilpc)
347
{
348
    double lsp[FILTER_ORDER];
349
    float a[FILTER_ORDER / 2 + 1], b[FILTER_ORDER / 2 + 1];
350
    float a1[FILTER_ORDER / 2] = { 0 };
351
    float a2[FILTER_ORDER / 2] = { 0 };
352
    float b1[FILTER_ORDER / 2] = { 0 };
353
    float b2[FILTER_ORDER / 2] = { 0 };
354
    int i, k;
355
356
    ff_acelp_lsf2lspd(lsp, ilspf, FILTER_ORDER);
357
358
    for (k = 0; k <= FILTER_ORDER; k++) {
359
        a[0] = k < 2 ? 0.25 : 0;
360
        b[0] = k < 2 ? k < 1 ? 0.25 : -0.25 : 0;
361
362
        for (i = 0; i < FILTER_ORDER / 2; i++) {
363
            a[i + 1] = a[i] - 2 * lsp[i * 2    ] * a1[i] + a2[i];
364
            b[i + 1] = b[i] - 2 * lsp[i * 2 + 1] * b1[i] + b2[i];
365
            a2[i] = a1[i];
366
            a1[i] = a[i];
367
            b2[i] = b1[i];
368
            b1[i] = b[i];
369
        }
370
371
        if (k)
372
            ilpc[k - 1] = 2.0 * (a[FILTER_ORDER / 2] + b[FILTER_ORDER / 2]);
373
    }
374
}
375
376
static void bl_intrp(EVRCContext *e, float *ex, float delay)
377
{
378
    float *f;
379
    int offset, i, coef_idx;
380
    int16_t t;
381
382
    offset = lrintf(delay);
383
384
    t = (offset - delay + 0.5) * 8.0 + 0.5;
385
    if (t == 8) {
386
        t = 0;
387
        offset--;
388
    }
389
390
    f = ex - offset - 8;
391
392
    coef_idx = t * (2 * 8 + 1);
393
394
    ex[0] = 0.0;
395
    for (i = 0; i < 2 * 8 + 1; i++)
396
        ex[0] += e->interpolation_coeffs[coef_idx + i] * f[i];
397
}
398
399
/*
400
 * Adaptive codebook excitation.
401
 *
402
 * TIA/IS-127 5.2.2.3.3, 4.12.5.2
403
 */
404
static void acb_excitation(EVRCContext *e, float *excitation, float gain,
405
                           const float delay[3], int length)
406
{
407
    float denom, locdelay, dpr, invl;
408
    int i;
409
410
    invl = 1.0 / ((float) length);
411
    dpr = length;
412
413
    /* first at-most extra samples */
414
    denom = (delay[1] - delay[0]) * invl;
415
    for (i = 0; i < dpr; i++) {
416
        locdelay = delay[0] + i * denom;
417
        bl_intrp(e, excitation + i, locdelay);
418
    }
419
420
    denom = (delay[2] - delay[1]) * invl;
421
    /* interpolation */
422
    for (i = dpr; i < dpr + 10; i++) {
423
        locdelay = delay[1] + (i - dpr) * denom;
424
        bl_intrp(e, excitation + i, locdelay);
425
    }
426
427
    for (i = 0; i < length; i++)
428
        excitation[i] *= gain;
429
}
430
431
static void decode_8_pulses_35bits(const uint16_t *fixed_index, float *cod)
432
{
433
    int i, pos1, pos2, offset;
434
435
    offset = (fixed_index[3] >> 9) & 3;
436
437
    for (i = 0; i < 3; i++) {
438
        pos1 = ((fixed_index[i] & 0x7f) / 11) * 5 + ((i + offset) % 5);
439
        pos2 = ((fixed_index[i] & 0x7f) % 11) * 5 + ((i + offset) % 5);
440
441
        cod[pos1] = (fixed_index[i] & 0x80) ? -1.0 : 1.0;
442
443
        if (pos2 < pos1)
444
            cod[pos2]  = -cod[pos1];
445
        else
446
            cod[pos2] +=  cod[pos1];
447
    }
448
449
    pos1 = ((fixed_index[3] & 0x7f) / 11) * 5 + ((3 + offset) % 5);
450
    pos2 = ((fixed_index[3] & 0x7f) % 11) * 5 + ((4 + offset) % 5);
451
452
    cod[pos1] = (fixed_index[3] & 0x100) ? -1.0 : 1.0;
453
    cod[pos2] = (fixed_index[3] & 0x80 ) ? -1.0 : 1.0;
454
}
455
456
static void decode_3_pulses_10bits(uint16_t fixed_index, float *cod)
457
{
458
    float sign;
459
    int pos;
460
461
    sign = (fixed_index & 0x200) ? -1.0 : 1.0;
462
463
    pos = ((fixed_index        & 0x7) * 7) + 4;
464
    cod[pos] += sign;
465
    pos = (((fixed_index >> 3) & 0x7) * 7) + 2;
466
    cod[pos] -= sign;
467
    pos = (((fixed_index >> 6) & 0x7) * 7);
468
    cod[pos] += sign;
469
}
470
471
/*
472
 * Reconstruction of ACELP fixed codebook excitation for full and half rate.
473
 *
474
 * TIA/IS-127 5.2.3.7
475
 */
476
static void fcb_excitation(EVRCContext *e, const uint16_t *codebook,
477
                           float *excitation, float pitch_gain,
478
                           int pitch_lag, int subframe_size)
479
{
480
    int i;
481
482
    if (e->bitrate == RATE_FULL)
483
        decode_8_pulses_35bits(codebook, excitation);
484
    else
485
        decode_3_pulses_10bits(*codebook, excitation);
486
487
    pitch_gain = av_clipf(pitch_gain, 0.2, 0.9);
488
489
    for (i = pitch_lag; i < subframe_size; i++)
490
        excitation[i] += pitch_gain * excitation[i - pitch_lag];
491
}
492
493
/**
494
 * Synthesis of the decoder output signal.
495
 *
496
 * param[in]     in              input signal
497
 * param[in]     filter_coeffs   LPC coefficients
498
 * param[in/out] memory          synthesis filter memory
499
 * param         buffer_length   amount of data to process
500
 * param[out]    samples         output samples
501
 *
502
 * TIA/IS-127 5.2.3.15, 5.7.3.4
503
 */
504
static void synthesis_filter(const float *in, const float *filter_coeffs,
505
                             float *memory, int buffer_length, float *samples)
506
{
507
    int i, j;
508
509
    for (i = 0; i < buffer_length; i++) {
510
        samples[i] = in[i];
511
        for (j = FILTER_ORDER - 1; j > 0; j--) {
512
            samples[i] -= filter_coeffs[j] * memory[j];
513
            memory[j]   = memory[j - 1];
514
        }
515
        samples[i] -= filter_coeffs[0] * memory[0];
516
        memory[0]   = samples[i];
517
    }
518
}
519
520
static void bandwidth_expansion(float *coeff, const float *inbuf, float gamma)
521
{
522
    double fac = gamma;
523
    int i;
524
525
    for (i = 0; i < FILTER_ORDER; i++) {
526
        coeff[i] = inbuf[i] * fac;
527
        fac *= gamma;
528
    }
529
}
530
531
static void residual_filter(float *output, const float *input,
532
                            const float *coef, float *memory, int length)
533
{
534
    float sum;
535
    int i, j;
536
537
    for (i = 0; i < length; i++) {
538
        sum = input[i];
539
540
        for (j = FILTER_ORDER - 1; j > 0; j--) {
541
            sum      += coef[j] * memory[j];
542
            memory[j] = memory[j - 1];
543
        }
544
        sum += coef[0] * memory[0];
545
        memory[0] = input[i];
546
        output[i] = sum;
547
    }
548
}
549
550
/*
551
 * TIA/IS-127 Table 5.9.1-1.
552
 */
553
static const struct PfCoeff {
554
    float tilt;
555
    float ltgain;
556
    float p1;
557
    float p2;
558
} postfilter_coeffs[5] = {
559
    { 0.0 , 0.0 , 0.0 , 0.0  },
560
    { 0.0 , 0.0 , 0.57, 0.57 },
561
    { 0.0 , 0.0 , 0.0 , 0.0  },
562
    { 0.35, 0.50, 0.50, 0.75 },
563
    { 0.20, 0.50, 0.57, 0.75 },
564
};
565
566
/*
567
 * Adaptive postfilter.
568
 *
569
 * TIA/IS-127 5.9
570
 */
571
static void postfilter(EVRCContext *e, float *in, const float *coeff,
572
                       float *out, int idx, const struct PfCoeff *pfc,
573
                       int length)
574
{
575
    float wcoef1[FILTER_ORDER], wcoef2[FILTER_ORDER],
576
          scratch[SUBFRAME_SIZE], temp[SUBFRAME_SIZE],
577
          mem[SUBFRAME_SIZE];
578
    float sum1 = 0.0, sum2 = 0.0, gamma, gain;
579
    float tilt = pfc->tilt;
580
    int i, n, best;
581
582
    bandwidth_expansion(wcoef1, coeff, pfc->p1);
583
    bandwidth_expansion(wcoef2, coeff, pfc->p2);
584
585
    /* Tilt compensation filter, TIA/IS-127 5.9.1 */
586
    for (i = 0; i < length - 1; i++)
587
        sum2 += in[i] * in[i + 1];
588
    if (sum2 < 0.0)
589
        tilt = 0.0;
590
591
    for (i = 0; i < length; i++) {
592
        scratch[i] = in[i] - tilt * e->last;
593
        e->last = in[i];
594
    }
595
596
    /* Short term residual filter, TIA/IS-127 5.9.2 */
597
    residual_filter(&e->postfilter_residual[ACB_SIZE], scratch, wcoef1, e->postfilter_fir, length);
598
599
    /* Long term postfilter */
600
    best = idx;
601
    for (i = FFMIN(MIN_DELAY, idx - 3); i <= FFMAX(MAX_DELAY, idx + 3); i++) {
602
        for (n = ACB_SIZE, sum2 = 0; n < ACB_SIZE + length; n++)
603
            sum2 += e->postfilter_residual[n] * e->postfilter_residual[n - i];
604
        if (sum2 > sum1) {
605
            sum1 = sum2;
606
            best = i;
607
        }
608
    }
609
610
    for (i = ACB_SIZE, sum1 = 0; i < ACB_SIZE + length; i++)
611
        sum1 += e->postfilter_residual[i - best] * e->postfilter_residual[i - best];
612
    for (i = ACB_SIZE, sum2 = 0; i < ACB_SIZE + length; i++)
613
        sum2 += e->postfilter_residual[i] * e->postfilter_residual[i - best];
614
615
    if (sum2 * sum1 == 0 || e->bitrate == RATE_QUANT) {
616
        memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));
617
    } else {
618
        gamma = sum2 / sum1;
619
        if (gamma < 0.5)
620
            memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));
621
        else {
622
            gamma = FFMIN(gamma, 1.0);
623
624
            for (i = 0; i < length; i++) {
625
                temp[i] = e->postfilter_residual[ACB_SIZE + i] + gamma *
626
                    pfc->ltgain * e->postfilter_residual[ACB_SIZE + i - best];
627
            }
628
        }
629
    }
630
631
    memcpy(scratch, temp, length * sizeof(float));
632
    memcpy(mem, e->postfilter_iir, FILTER_ORDER * sizeof(float));
633
    synthesis_filter(scratch, wcoef2, mem, length, scratch);
634
635
    /* Gain computation, TIA/IS-127 5.9.4-2 */
636
    for (i = 0, sum1 = 0, sum2 = 0; i < length; i++) {
637
        sum1 += in[i] * in[i];
638
        sum2 += scratch[i] * scratch[i];
639
    }
640
    gain = sum2 ? sqrt(sum1 / sum2) : 1.0;
641
642
    for (i = 0; i < length; i++)
643
        temp[i] *= gain;
644
645
    /* Short term postfilter */
646
    synthesis_filter(temp, wcoef2, e->postfilter_iir, length, out);
647
648
    memmove(e->postfilter_residual,
649
           e->postfilter_residual + length, ACB_SIZE * sizeof(float));
650
}
651
652
static void frame_erasure(EVRCContext *e, float *samples)
653
{
654
    float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES],
655
          tmp[SUBFRAME_SIZE + 6], f;
656
    int i, j;
657
658
    for (i = 0; i < FILTER_ORDER; i++) {
659
        if (e->bitrate != RATE_QUANT)
660
            e->lspf[i] = e->prev_lspf[i] * 0.875 + 0.125 * (i + 1) * 0.048;
661
        else
662
            e->lspf[i] = e->prev_lspf[i];
663
    }
664
665
    if (e->prev_error_flag)
666
        e->avg_acb_gain *= 0.75;
667
    if (e->bitrate == RATE_FULL)
668
        memcpy(e->pitch_back, e->pitch, ACB_SIZE * sizeof(float));
669
    if (e->last_valid_bitrate == RATE_QUANT)
670
        e->bitrate = RATE_QUANT;
671
    else
672
        e->bitrate = RATE_FULL;
673
674
    if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {
675
        e->pitch_delay = e->prev_pitch_delay;
676
    } else {
677
        float sum = 0;
678
679
        idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;
680
681
        for (i = 0; i < NB_SUBFRAMES; i++)
682
            sum += evrc_energy_quant[e->prev_energy_gain][i];
683
        sum /= (float) NB_SUBFRAMES;
684
        sum  = pow(10, sum);
685
        for (i = 0; i < NB_SUBFRAMES; i++)
686
            e->energy_vector[i] = sum;
687
    }
688
689
    if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)
690
        e->prev_pitch_delay = e->pitch_delay;
691
692
    for (i = 0; i < NB_SUBFRAMES; i++) {
693
        int subframe_size = subframe_sizes[i];
694
        int pitch_lag;
695
696
        interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);
697
698
        if (e->bitrate != RATE_QUANT) {
699
            if (e->avg_acb_gain < 0.3) {
700
                idelay[0] = estimation_delay[i];
701
                idelay[1] = estimation_delay[i + 1];
702
                idelay[2] = estimation_delay[i + 2];
703
            } else {
704
                interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);
705
            }
706
        }
707
708
        pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);
709
        decode_predictor_coeffs(ilspf, ilpc);
710
711
        if (e->bitrate != RATE_QUANT) {
712
            acb_excitation(e, e->pitch + ACB_SIZE,
713
                           e->avg_acb_gain, idelay, subframe_size);
714
            for (j = 0; j < subframe_size; j++)
715
                e->pitch[ACB_SIZE + j] *= e->fade_scale;
716
            e->fade_scale = FFMAX(e->fade_scale - 0.05, 0.0);
717
        } else {
718
            for (j = 0; j < subframe_size; j++)
719
                e->pitch[ACB_SIZE + j] = e->energy_vector[i];
720
        }
721
722
        memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
723
724
        if (e->bitrate != RATE_QUANT && e->avg_acb_gain < 0.4) {
725
            f = 0.1 * e->avg_fcb_gain;
726
            for (j = 0; j < subframe_size; j++)
727
                e->pitch[ACB_SIZE + j] += f;
728
        } else if (e->bitrate == RATE_QUANT) {
729
            for (j = 0; j < subframe_size; j++)
730
                e->pitch[ACB_SIZE + j] = e->energy_vector[i];
731
        }
732
733
        synthesis_filter(e->pitch + ACB_SIZE, ilpc,
734
                         e->synthesis, subframe_size, tmp);
735
        postfilter(e, tmp, ilpc, samples, pitch_lag,
736
                   &postfilter_coeffs[e->bitrate], subframe_size);
737
738
        samples += subframe_size;
739
    }
740
}
741
742
static int evrc_decode_frame(AVCodecContext *avctx, void *data,
743
                             int *got_frame_ptr, AVPacket *avpkt)
744
{
745
    const uint8_t *buf = avpkt->data;
746
    AVFrame *frame     = data;
747
    EVRCContext *e     = avctx->priv_data;
748
    int buf_size       = avpkt->size;
749
    float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES];
750
    float *samples;
751
    int   i, j, ret, error_flag = 0;
752
753
    frame->nb_samples = 160;
754
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
755
        return ret;
756
    samples = (float *)frame->data[0];
757
758
    if ((e->bitrate = determine_bitrate(avctx, &buf_size, &buf)) == RATE_ERRS) {
759
        warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");
760
        goto erasure;
761
    }
762
    if (e->bitrate <= SILENCE || e->bitrate == RATE_QUARTER)
763
        goto erasure;
764
    if (e->bitrate == RATE_QUANT && e->last_valid_bitrate == RATE_FULL
765
                                 && !e->prev_error_flag)
766
        goto erasure;
767
768
    if ((ret = init_get_bits8(&e->gb, buf, buf_size)) < 0)
769
        return ret;
770
    memset(&e->frame, 0, sizeof(EVRCAFrame));
771
772
    unpack_frame(e);
773
774
    if (e->bitrate != RATE_QUANT) {
775
        uint8_t *p = (uint8_t *) &e->frame;
776
        for (i = 0; i < sizeof(EVRCAFrame); i++) {
777
            if (p[i])
778
                break;
779
        }
780
        if (i == sizeof(EVRCAFrame))
781
            goto erasure;
782
    } else if (e->frame.lsp[0] == 0xf &&
783
               e->frame.lsp[1] == 0xf &&
784
               e->frame.energy_gain == 0xff) {
785
        goto erasure;
786
    }
787
788
    if (decode_lspf(e) < 0)
789
        goto erasure;
790
791
    if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {
792
        /* Pitch delay parameter checking as per TIA/IS-127 5.1.5.1 */
793
        if (e->frame.pitch_delay > MAX_DELAY - MIN_DELAY)
794
            goto erasure;
795
796
        e->pitch_delay = e->frame.pitch_delay + MIN_DELAY;
797
798
        /* Delay diff parameter checking as per TIA/IS-127 5.1.5.2 */
799
        if (e->frame.delay_diff) {
800
            int p = e->pitch_delay - e->frame.delay_diff + 16;
801
            if (p < MIN_DELAY || p > MAX_DELAY)
802
                goto erasure;
803
        }
804
805
        /* Delay contour reconstruction as per TIA/IS-127 5.2.2.2 */
806
        if (e->frame.delay_diff &&
807
            e->bitrate == RATE_FULL && e->prev_error_flag) {
808
            float delay;
809
810
            memcpy(e->pitch, e->pitch_back, ACB_SIZE * sizeof(float));
811
812
            delay = e->prev_pitch_delay;
813
            e->prev_pitch_delay = delay - e->frame.delay_diff + 16.0;
814
815
            if (fabs(e->pitch_delay - delay) > 15)
816
                delay = e->pitch_delay;
817
818
            for (i = 0; i < NB_SUBFRAMES; i++) {
819
                int subframe_size = subframe_sizes[i];
820
821
                interpolate_delay(idelay, delay, e->prev_pitch_delay, i);
822
                acb_excitation(e, e->pitch + ACB_SIZE, e->avg_acb_gain, idelay, subframe_size);
823
                memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
824
            }
825
        }
826
827
        /* Smoothing of the decoded delay as per TIA/IS-127 5.2.2.5 */
828
        if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)
829
            e->prev_pitch_delay = e->pitch_delay;
830
831
        e->avg_acb_gain = e->avg_fcb_gain = 0.0;
832
    } else {
833
        idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;
834
835
        /* Decode frame energy vectors as per TIA/IS-127 5.7.2 */
836
        for (i = 0; i < NB_SUBFRAMES; i++)
837
            e->energy_vector[i] = pow(10, evrc_energy_quant[e->frame.energy_gain][i]);
838
        e->prev_energy_gain = e->frame.energy_gain;
839
    }
840
841
    for (i = 0; i < NB_SUBFRAMES; i++) {
842
        float tmp[SUBFRAME_SIZE + 6] = { 0 };
843
        int subframe_size = subframe_sizes[i];
844
        int pitch_lag;
845
846
        interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);
847
848
        if (e->bitrate != RATE_QUANT)
849
            interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);
850
851
        pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);
852
        decode_predictor_coeffs(ilspf, ilpc);
853
854
        /* Bandwidth expansion as per TIA/IS-127 5.2.3.3 */
855
        if (e->frame.lpc_flag && e->prev_error_flag)
856
            bandwidth_expansion(ilpc, ilpc, 0.75);
857
858
        if (e->bitrate != RATE_QUANT) {
859
            float acb_sum, f;
860
861
            f = exp((e->bitrate == RATE_HALF ? 0.5 : 0.25)
862
                         * (e->frame.fcb_gain[i] + 1));
863
            acb_sum = pitch_gain_vq[e->frame.acb_gain[i]];
864
            e->avg_acb_gain += acb_sum / NB_SUBFRAMES;
865
            e->avg_fcb_gain += f / NB_SUBFRAMES;
866
867
            acb_excitation(e, e->pitch + ACB_SIZE,
868
                           acb_sum, idelay, subframe_size);
869
            fcb_excitation(e, e->frame.fcb_shape[i], tmp,
870
                           acb_sum, pitch_lag, subframe_size);
871
872
            /* Total excitation generation as per TIA/IS-127 5.2.3.9 */
873
            for (j = 0; j < subframe_size; j++)
874
                e->pitch[ACB_SIZE + j] += f * tmp[j];
875
            e->fade_scale = FFMIN(e->fade_scale + 0.2, 1.0);
876
        } else {
877
            for (j = 0; j < subframe_size; j++)
878
                e->pitch[ACB_SIZE + j] = e->energy_vector[i];
879
        }
880
881
        memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));
882
883
        synthesis_filter(e->pitch + ACB_SIZE, ilpc,
884
                         e->synthesis, subframe_size,
885
                         e->postfilter ? tmp : samples);
886
        if (e->postfilter)
887
            postfilter(e, tmp, ilpc, samples, pitch_lag,
888
                       &postfilter_coeffs[e->bitrate], subframe_size);
889
890
        samples += subframe_size;
891
    }
892
893
    if (error_flag) {
894
erasure:
895
        error_flag = 1;
896
        av_log(avctx, AV_LOG_WARNING, "frame erasure\n");
897
        frame_erasure(e, samples);
898
    }
899
900
    memcpy(e->prev_lspf, e->lspf, sizeof(e->prev_lspf));
901
    e->prev_error_flag    = error_flag;
902
    e->last_valid_bitrate = e->bitrate;
903
904
    if (e->bitrate != RATE_QUANT)
905
        e->prev_pitch_delay = e->pitch_delay;
906
907
    samples = (float *)frame->data[0];
908
    for (i = 0; i < 160; i++)
909
        samples[i] /= 32768;
910
911
    *got_frame_ptr   = 1;
912
913
    return avpkt->size;
914
}
915
916
#define OFFSET(x) offsetof(EVRCContext, x)
917
#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
918
919
static const AVOption options[] = {
920
    { "postfilter", "enable postfilter", OFFSET(postfilter), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AD },
921
    { NULL }
922
};
923
924
static const AVClass evrcdec_class = {
925
    .class_name = "evrc",
926
    .item_name  = av_default_item_name,
927
    .option     = options,
928
    .version    = LIBAVUTIL_VERSION_INT,
929
};
930
931
AVCodec ff_evrc_decoder = {
932
    .name           = "evrc",
933
    .long_name      = NULL_IF_CONFIG_SMALL("EVRC (Enhanced Variable Rate Codec)"),
934
    .type           = AVMEDIA_TYPE_AUDIO,
935
    .id             = AV_CODEC_ID_EVRC,
936
    .init           = evrc_decode_init,
937
    .decode         = evrc_decode_frame,
938
    .capabilities   = AV_CODEC_CAP_DR1,
939
    .priv_data_size = sizeof(EVRCContext),
940
    .priv_class     = &evrcdec_class,
941
};