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1/*
2 * Enhanced Variable Rate Codec, Service Option 3 decoder
3 * Copyright (c) 2013 Paul B Mahol
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 * 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
45typedef enum {
46 RATE_ERRS = -1,
47 SILENCE,
48 RATE_QUANT,
49 RATE_QUARTER,
50 RATE_HALF,
51 RATE_FULL,
52} evrc_packet_rate;
53
54/**
55 * EVRC-A unpacked data frame
56 */
57typedef 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
69typedef 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 */
108static 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);
119 frame->lsp[3] = get_bits(gb, 7);
120 frame->pitch_delay = get_bits(gb, 7);
121 frame->delay_diff = get_bits(gb, 5);
122 frame->acb_gain[0] = get_bits(gb, 3);
123 frame->fcb_shape[0][0] = get_bits(gb, 8);
124 frame->fcb_shape[0][1] = get_bits(gb, 8);
125 frame->fcb_shape[0][2] = get_bits(gb, 8);
126 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);
129 frame->fcb_shape[1][0] = get_bits(gb, 8);
130 frame->fcb_shape[1][1] = get_bits(gb, 8);
131 frame->fcb_shape[1][2] = get_bits(gb, 8);
132 frame->fcb_shape[1][3] = get_bits(gb, 11);
133 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);
138 frame->fcb_shape[2][3] = get_bits(gb, 11);
139 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);
144 frame->lsp [1] = get_bits(gb, 7);
145 frame->lsp [2] = get_bits(gb, 8);
146 frame->pitch_delay = get_bits(gb, 7);
147 frame->acb_gain [0] = get_bits(gb, 3);
148 frame->fcb_shape[0][0] = get_bits(gb, 10);
149 frame->fcb_gain [0] = get_bits(gb, 4);
150 frame->acb_gain [1] = get_bits(gb, 3);
151 frame->fcb_shape[1][0] = get_bits(gb, 10);
152 frame->fcb_gain [1] = get_bits(gb, 4);
153 frame->acb_gain [2] = get_bits(gb, 3);
154 frame->fcb_shape[2][0] = get_bits(gb, 10);
155 frame->fcb_gain [2] = get_bits(gb, 4);
156 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
165static 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 */
188static 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
219static 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 */
231static 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 */
282static 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 */
315static 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 */
329static 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 */
346static 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
376static 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 */
404static 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
431static 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
456static 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 */
476static 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 */
504static 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
520static 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
531static 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 */
553static 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 */
571static 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
652static 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
742static 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) {
894erasure:
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
919static const AVOption options[] = {
920 { "postfilter", "enable postfilter", OFFSET(postfilter), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AD },
921 { NULL }
922};
923
924static 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
931AVCodec 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};
942
generated by cgit at 2024-05-17 05:02:24 (GMT)