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/channel_layout.h" 29#include "libavutil/mathematics.h" 30#include "libavutil/opt.h" 31#include "avcodec.h" 32#include "codec_internal.h" 33#include "internal.h" 34#include "get_bits.h" 35#include "evrcdata.h" 36#include "acelp_vectors.h" 37#include "lsp.h" 38 39#define MIN_LSP_SEP (0.05 / (2.0 * M_PI)) 40#define MIN_DELAY 20 41#define MAX_DELAY 120 42#define NB_SUBFRAMES 3 43#define SUBFRAME_SIZE 54 44#define FILTER_ORDER 10 45#define ACB_SIZE 128 46 47typedef enum { 48 RATE_ERRS = -1, 49 SILENCE, 50 RATE_QUANT, 51 RATE_QUARTER, 52 RATE_HALF, 53 RATE_FULL, 54} evrc_packet_rate; 55 56/** 57 * EVRC-A unpacked data frame 58 */ 59typedef struct EVRCAFrame { 60 uint8_t lpc_flag; ///< spectral change indicator 61 uint16_t lsp[4]; ///< index into LSP codebook 62 uint8_t pitch_delay; ///< pitch delay for entire frame 63 uint8_t delay_diff; ///< delay difference for entire frame 64 uint8_t acb_gain[3]; ///< adaptive codebook gain 65 uint16_t fcb_shape[3][4]; ///< fixed codebook shape 66 uint8_t fcb_gain[3]; ///< fixed codebook gain index 67 uint8_t energy_gain; ///< frame energy gain index 68 uint8_t tty; ///< tty baud rate bit 69} EVRCAFrame; 70 71typedef struct EVRCContext { 72 AVClass *class; 73 74 int postfilter; 75 76 GetBitContext gb; 77 evrc_packet_rate bitrate; 78 evrc_packet_rate last_valid_bitrate; 79 EVRCAFrame frame; 80 81 float lspf[FILTER_ORDER]; 82 float prev_lspf[FILTER_ORDER]; 83 float synthesis[FILTER_ORDER]; 84 float postfilter_fir[FILTER_ORDER]; 85 float postfilter_iir[FILTER_ORDER]; 86 float postfilter_residual[ACB_SIZE + SUBFRAME_SIZE]; 87 float pitch_delay; 88 float prev_pitch_delay; 89 float avg_acb_gain; ///< average adaptive codebook gain 90 float avg_fcb_gain; ///< average fixed codebook gain 91 float pitch[ACB_SIZE + FILTER_ORDER + SUBFRAME_SIZE]; 92 float pitch_back[ACB_SIZE]; 93 float interpolation_coeffs[136]; 94 float energy_vector[NB_SUBFRAMES]; 95 float fade_scale; 96 float last; 97 98 uint8_t prev_energy_gain; 99 uint8_t prev_error_flag; 100 uint8_t warned_buf_mismatch_bitrate; 101} EVRCContext; 102 103/** 104 * Frame unpacking for RATE_FULL, RATE_HALF and RATE_QUANT 105 * 106 * @param e the context 107 * 108 * TIA/IS-127 Table 4.21-1 109 */ 110static void unpack_frame(EVRCContext *e) 111{ 112 EVRCAFrame *frame = &e->frame; 113 GetBitContext *gb = &e->gb; 114 115 switch (e->bitrate) { 116 case RATE_FULL: 117 frame->lpc_flag = get_bits1(gb); 118 frame->lsp[0] = get_bits(gb, 6); 119 frame->lsp[1] = get_bits(gb, 6); 120 frame->lsp[2] = get_bits(gb, 9); 121 frame->lsp[3] = get_bits(gb, 7); 122 frame->pitch_delay = get_bits(gb, 7); 123 frame->delay_diff = get_bits(gb, 5); 124 frame->acb_gain[0] = get_bits(gb, 3); 125 frame->fcb_shape[0][0] = get_bits(gb, 8); 126 frame->fcb_shape[0][1] = get_bits(gb, 8); 127 frame->fcb_shape[0][2] = get_bits(gb, 8); 128 frame->fcb_shape[0][3] = get_bits(gb, 11); 129 frame->fcb_gain[0] = get_bits(gb, 5); 130 frame->acb_gain[1] = get_bits(gb, 3); 131 frame->fcb_shape[1][0] = get_bits(gb, 8); 132 frame->fcb_shape[1][1] = get_bits(gb, 8); 133 frame->fcb_shape[1][2] = get_bits(gb, 8); 134 frame->fcb_shape[1][3] = get_bits(gb, 11); 135 frame->fcb_gain [1] = get_bits(gb, 5); 136 frame->acb_gain [2] = get_bits(gb, 3); 137 frame->fcb_shape[2][0] = get_bits(gb, 8); 138 frame->fcb_shape[2][1] = get_bits(gb, 8); 139 frame->fcb_shape[2][2] = get_bits(gb, 8); 140 frame->fcb_shape[2][3] = get_bits(gb, 11); 141 frame->fcb_gain [2] = get_bits(gb, 5); 142 frame->tty = get_bits1(gb); 143 break; 144 case RATE_HALF: 145 frame->lsp [0] = get_bits(gb, 7); 146 frame->lsp [1] = get_bits(gb, 7); 147 frame->lsp [2] = get_bits(gb, 8); 148 frame->pitch_delay = get_bits(gb, 7); 149 frame->acb_gain [0] = get_bits(gb, 3); 150 frame->fcb_shape[0][0] = get_bits(gb, 10); 151 frame->fcb_gain [0] = get_bits(gb, 4); 152 frame->acb_gain [1] = get_bits(gb, 3); 153 frame->fcb_shape[1][0] = get_bits(gb, 10); 154 frame->fcb_gain [1] = get_bits(gb, 4); 155 frame->acb_gain [2] = get_bits(gb, 3); 156 frame->fcb_shape[2][0] = get_bits(gb, 10); 157 frame->fcb_gain [2] = get_bits(gb, 4); 158 break; 159 case RATE_QUANT: 160 frame->lsp [0] = get_bits(gb, 4); 161 frame->lsp [1] = get_bits(gb, 4); 162 frame->energy_gain = get_bits(gb, 8); 163 break; 164 } 165} 166 167static evrc_packet_rate buf_size2bitrate(const int buf_size) 168{ 169 switch (buf_size) { 170 case 23: return RATE_FULL; 171 case 11: return RATE_HALF; 172 case 6: return RATE_QUARTER; 173 case 3: return RATE_QUANT; 174 case 1: return SILENCE; 175 } 176 177 return RATE_ERRS; 178} 179 180/** 181 * Determine the bitrate from the frame size and/or the first byte of the frame. 182 * 183 * @param avctx the AV codec context 184 * @param buf_size length of the buffer 185 * @param buf the bufffer 186 * 187 * @return the bitrate on success, 188 * RATE_ERRS if the bitrate cannot be satisfactorily determined 189 */ 190static evrc_packet_rate determine_bitrate(AVCodecContext *avctx, 191 int *buf_size, 192 const uint8_t **buf) 193{ 194 evrc_packet_rate bitrate; 195 196 if ((bitrate = buf_size2bitrate(*buf_size)) >= 0) { 197 if (bitrate > **buf) { 198 EVRCContext *e = avctx->priv_data; 199 if (!e->warned_buf_mismatch_bitrate) { 200 av_log(avctx, AV_LOG_WARNING, 201 "Claimed bitrate and buffer size mismatch.\n"); 202 e->warned_buf_mismatch_bitrate = 1; 203 } 204 bitrate = **buf; 205 } else if (bitrate < **buf) { 206 av_log(avctx, AV_LOG_ERROR, 207 "Buffer is too small for the claimed bitrate.\n"); 208 return RATE_ERRS; 209 } 210 (*buf)++; 211 *buf_size -= 1; 212 } else if ((bitrate = buf_size2bitrate(*buf_size + 1)) >= 0) { 213 av_log(avctx, AV_LOG_DEBUG, 214 "Bitrate byte is missing, guessing the bitrate from packet size.\n"); 215 } else 216 return RATE_ERRS; 217 218 return bitrate; 219} 220 221static void warn_insufficient_frame_quality(AVCodecContext *avctx, 222 const char *message) 223{ 224 av_log(avctx, AV_LOG_WARNING, "Frame #%d, %s\n", 225 avctx->frame_number, message); 226} 227 228/** 229 * Initialize the speech codec according to the specification. 230 * 231 * TIA/IS-127 5.2 232 */ 233static av_cold int evrc_decode_init(AVCodecContext *avctx) 234{ 235 EVRCContext *e = avctx->priv_data; 236 int i, n, idx = 0; 237 float denom = 2.0 / (2.0 * 8.0 + 1.0); 238 239 av_channel_layout_uninit(&avctx->ch_layout); 240 avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO; 241 avctx->sample_fmt = AV_SAMPLE_FMT_FLT; 242 243 for (i = 0; i < FILTER_ORDER; i++) { 244 e->prev_lspf[i] = (i + 1) * 0.048; 245 e->synthesis[i] = 0.0; 246 } 247 248 for (i = 0; i < ACB_SIZE; i++) 249 e->pitch[i] = e->pitch_back[i] = 0.0; 250 251 e->last_valid_bitrate = RATE_QUANT; 252 e->prev_pitch_delay = 40.0; 253 e->fade_scale = 1.0; 254 e->prev_error_flag = 0; 255 e->avg_acb_gain = e->avg_fcb_gain = 0.0; 256 257 for (i = 0; i < 8; i++) { 258 float tt = ((float)i - 8.0 / 2.0) / 8.0; 259 260 for (n = -8; n <= 8; n++, idx++) { 261 float arg1 = M_PI * 0.9 * (tt - n); 262 float arg2 = M_PI * (tt - n); 263 264 e->interpolation_coeffs[idx] = 0.9; 265 if (arg1) 266 e->interpolation_coeffs[idx] *= (0.54 + 0.46 * cos(arg2 * denom)) * 267 sin(arg1) / arg1; 268 } 269 } 270 271 return 0; 272} 273 274/** 275 * Decode the 10 vector quantized line spectral pair frequencies from the LSP 276 * transmission codes of any bitrate and check for badly received packets. 277 * 278 * @param e the context 279 * 280 * @return 0 on success, -1 if the packet is badly received 281 * 282 * TIA/IS-127 5.2.1, 5.7.1 283 */ 284static int decode_lspf(EVRCContext *e) 285{ 286 const float * const *codebooks = evrc_lspq_codebooks[e->bitrate]; 287 int i, j, k = 0; 288 289 for (i = 0; i < evrc_lspq_nb_codebooks[e->bitrate]; i++) { 290 int row_size = evrc_lspq_codebooks_row_sizes[e->bitrate][i]; 291 const float *codebook = codebooks[i]; 292 293 for (j = 0; j < row_size; j++) 294 e->lspf[k++] = codebook[e->frame.lsp[i] * row_size + j]; 295 } 296 297 // check for monotonic LSPs 298 for (i = 1; i < FILTER_ORDER; i++) 299 if (e->lspf[i] <= e->lspf[i - 1]) 300 return -1; 301 302 // check for minimum separation of LSPs at the splits 303 for (i = 0, k = 0; i < evrc_lspq_nb_codebooks[e->bitrate] - 1; i++) { 304 k += evrc_lspq_codebooks_row_sizes[e->bitrate][i]; 305 if (e->lspf[k] - e->lspf[k - 1] <= MIN_LSP_SEP) 306 return -1; 307 } 308 309 return 0; 310} 311 312/* 313 * Interpolation of LSP parameters. 314 * 315 * TIA/IS-127 5.2.3.1, 5.7.3.2 316 */ 317static void interpolate_lsp(float *ilsp, const float *lsp, 318 const float *prev, int index) 319{ 320 static const float lsp_interpolation_factors[] = { 0.1667, 0.5, 0.8333 }; 321 ff_weighted_vector_sumf(ilsp, prev, lsp, 322 1.0 - lsp_interpolation_factors[index], 323 lsp_interpolation_factors[index], FILTER_ORDER); 324} 325 326/* 327 * Reconstruction of the delay contour. 328 * 329 * TIA/IS-127 5.2.2.3.2 330 */ 331static void interpolate_delay(float *dst, float current, float prev, int index) 332{ 333 static const float d_interpolation_factors[] = { 0, 0.3313, 0.6625, 1, 1 }; 334 dst[0] = (1.0 - d_interpolation_factors[index ]) * prev 335 + d_interpolation_factors[index ] * current; 336 dst[1] = (1.0 - d_interpolation_factors[index + 1]) * prev 337 + d_interpolation_factors[index + 1] * current; 338 dst[2] = (1.0 - d_interpolation_factors[index + 2]) * prev 339 + d_interpolation_factors[index + 2] * current; 340} 341 342/* 343 * Convert the quantized, interpolated line spectral frequencies, 344 * to prediction coefficients. 345 * 346 * TIA/IS-127 5.2.3.2, 4.7.2.2 347 */ 348static void decode_predictor_coeffs(const float *ilspf, float *ilpc) 349{ 350 double lsp[FILTER_ORDER]; 351 float a[FILTER_ORDER / 2 + 1], b[FILTER_ORDER / 2 + 1]; 352 float a1[FILTER_ORDER / 2] = { 0 }; 353 float a2[FILTER_ORDER / 2] = { 0 }; 354 float b1[FILTER_ORDER / 2] = { 0 }; 355 float b2[FILTER_ORDER / 2] = { 0 }; 356 int i, k; 357 358 ff_acelp_lsf2lspd(lsp, ilspf, FILTER_ORDER); 359 360 for (k = 0; k <= FILTER_ORDER; k++) { 361 a[0] = k < 2 ? 0.25 : 0; 362 b[0] = k < 2 ? k < 1 ? 0.25 : -0.25 : 0; 363 364 for (i = 0; i < FILTER_ORDER / 2; i++) { 365 a[i + 1] = a[i] - 2 * lsp[i * 2 ] * a1[i] + a2[i]; 366 b[i + 1] = b[i] - 2 * lsp[i * 2 + 1] * b1[i] + b2[i]; 367 a2[i] = a1[i]; 368 a1[i] = a[i]; 369 b2[i] = b1[i]; 370 b1[i] = b[i]; 371 } 372 373 if (k) 374 ilpc[k - 1] = 2.0 * (a[FILTER_ORDER / 2] + b[FILTER_ORDER / 2]); 375 } 376} 377 378static void bl_intrp(EVRCContext *e, float *ex, float delay) 379{ 380 float *f; 381 int offset, i, coef_idx; 382 int16_t t; 383 384 offset = lrintf(delay); 385 386 t = (offset - delay + 0.5) * 8.0 + 0.5; 387 if (t == 8) { 388 t = 0; 389 offset--; 390 } 391 392 f = ex - offset - 8; 393 394 coef_idx = t * (2 * 8 + 1); 395 396 ex[0] = 0.0; 397 for (i = 0; i < 2 * 8 + 1; i++) 398 ex[0] += e->interpolation_coeffs[coef_idx + i] * f[i]; 399} 400 401/* 402 * Adaptive codebook excitation. 403 * 404 * TIA/IS-127 5.2.2.3.3, 4.12.5.2 405 */ 406static void acb_excitation(EVRCContext *e, float *excitation, float gain, 407 const float delay[3], int length) 408{ 409 float denom, locdelay, dpr, invl; 410 int i; 411 412 invl = 1.0 / ((float) length); 413 dpr = length; 414 415 /* first at-most extra samples */ 416 denom = (delay[1] - delay[0]) * invl; 417 for (i = 0; i < dpr; i++) { 418 locdelay = delay[0] + i * denom; 419 bl_intrp(e, excitation + i, locdelay); 420 } 421 422 denom = (delay[2] - delay[1]) * invl; 423 /* interpolation */ 424 for (i = dpr; i < dpr + 10; i++) { 425 locdelay = delay[1] + (i - dpr) * denom; 426 bl_intrp(e, excitation + i, locdelay); 427 } 428 429 for (i = 0; i < length; i++) 430 excitation[i] *= gain; 431} 432 433static void decode_8_pulses_35bits(const uint16_t *fixed_index, float *cod) 434{ 435 int i, pos1, pos2, offset; 436 437 offset = (fixed_index[3] >> 9) & 3; 438 439 for (i = 0; i < 3; i++) { 440 pos1 = ((fixed_index[i] & 0x7f) / 11) * 5 + ((i + offset) % 5); 441 pos2 = ((fixed_index[i] & 0x7f) % 11) * 5 + ((i + offset) % 5); 442 443 cod[pos1] = (fixed_index[i] & 0x80) ? -1.0 : 1.0; 444 445 if (pos2 < pos1) 446 cod[pos2] = -cod[pos1]; 447 else 448 cod[pos2] += cod[pos1]; 449 } 450 451 pos1 = ((fixed_index[3] & 0x7f) / 11) * 5 + ((3 + offset) % 5); 452 pos2 = ((fixed_index[3] & 0x7f) % 11) * 5 + ((4 + offset) % 5); 453 454 cod[pos1] = (fixed_index[3] & 0x100) ? -1.0 : 1.0; 455 cod[pos2] = (fixed_index[3] & 0x80 ) ? -1.0 : 1.0; 456} 457 458static void decode_3_pulses_10bits(uint16_t fixed_index, float *cod) 459{ 460 float sign; 461 int pos; 462 463 sign = (fixed_index & 0x200) ? -1.0 : 1.0; 464 465 pos = ((fixed_index & 0x7) * 7) + 4; 466 cod[pos] += sign; 467 pos = (((fixed_index >> 3) & 0x7) * 7) + 2; 468 cod[pos] -= sign; 469 pos = (((fixed_index >> 6) & 0x7) * 7); 470 cod[pos] += sign; 471} 472 473/* 474 * Reconstruction of ACELP fixed codebook excitation for full and half rate. 475 * 476 * TIA/IS-127 5.2.3.7 477 */ 478static void fcb_excitation(EVRCContext *e, const uint16_t *codebook, 479 float *excitation, float pitch_gain, 480 int pitch_lag, int subframe_size) 481{ 482 int i; 483 484 if (e->bitrate == RATE_FULL) 485 decode_8_pulses_35bits(codebook, excitation); 486 else 487 decode_3_pulses_10bits(*codebook, excitation); 488 489 pitch_gain = av_clipf(pitch_gain, 0.2, 0.9); 490 491 for (i = pitch_lag; i < subframe_size; i++) 492 excitation[i] += pitch_gain * excitation[i - pitch_lag]; 493} 494 495/** 496 * Synthesis of the decoder output signal. 497 * 498 * param[in] in input signal 499 * param[in] filter_coeffs LPC coefficients 500 * param[in/out] memory synthesis filter memory 501 * param buffer_length amount of data to process 502 * param[out] samples output samples 503 * 504 * TIA/IS-127 5.2.3.15, 5.7.3.4 505 */ 506static void synthesis_filter(const float *in, const float *filter_coeffs, 507 float *memory, int buffer_length, float *samples) 508{ 509 int i, j; 510 511 for (i = 0; i < buffer_length; i++) { 512 samples[i] = in[i]; 513 for (j = FILTER_ORDER - 1; j > 0; j--) { 514 samples[i] -= filter_coeffs[j] * memory[j]; 515 memory[j] = memory[j - 1]; 516 } 517 samples[i] -= filter_coeffs[0] * memory[0]; 518 memory[0] = samples[i]; 519 } 520} 521 522static void bandwidth_expansion(float *coeff, const float *inbuf, float gamma) 523{ 524 double fac = gamma; 525 int i; 526 527 for (i = 0; i < FILTER_ORDER; i++) { 528 coeff[i] = inbuf[i] * fac; 529 fac *= gamma; 530 } 531} 532 533static void residual_filter(float *output, const float *input, 534 const float *coef, float *memory, int length) 535{ 536 float sum; 537 int i, j; 538 539 for (i = 0; i < length; i++) { 540 sum = input[i]; 541 542 for (j = FILTER_ORDER - 1; j > 0; j--) { 543 sum += coef[j] * memory[j]; 544 memory[j] = memory[j - 1]; 545 } 546 sum += coef[0] * memory[0]; 547 memory[0] = input[i]; 548 output[i] = sum; 549 } 550} 551 552/* 553 * TIA/IS-127 Table 5.9.1-1. 554 */ 555static const struct PfCoeff { 556 float tilt; 557 float ltgain; 558 float p1; 559 float p2; 560} postfilter_coeffs[5] = { 561 { 0.0 , 0.0 , 0.0 , 0.0 }, 562 { 0.0 , 0.0 , 0.57, 0.57 }, 563 { 0.0 , 0.0 , 0.0 , 0.0 }, 564 { 0.35, 0.50, 0.50, 0.75 }, 565 { 0.20, 0.50, 0.57, 0.75 }, 566}; 567 568/* 569 * Adaptive postfilter. 570 * 571 * TIA/IS-127 5.9 572 */ 573static void postfilter(EVRCContext *e, float *in, const float *coeff, 574 float *out, int idx, const struct PfCoeff *pfc, 575 int length) 576{ 577 float wcoef1[FILTER_ORDER], wcoef2[FILTER_ORDER], 578 scratch[SUBFRAME_SIZE], temp[SUBFRAME_SIZE], 579 mem[SUBFRAME_SIZE]; 580 float sum1 = 0.0, sum2 = 0.0, gamma, gain; 581 float tilt = pfc->tilt; 582 int i, n, best; 583 584 bandwidth_expansion(wcoef1, coeff, pfc->p1); 585 bandwidth_expansion(wcoef2, coeff, pfc->p2); 586 587 /* Tilt compensation filter, TIA/IS-127 5.9.1 */ 588 for (i = 0; i < length - 1; i++) 589 sum2 += in[i] * in[i + 1]; 590 if (sum2 < 0.0) 591 tilt = 0.0; 592 593 for (i = 0; i < length; i++) { 594 scratch[i] = in[i] - tilt * e->last; 595 e->last = in[i]; 596 } 597 598 /* Short term residual filter, TIA/IS-127 5.9.2 */ 599 residual_filter(&e->postfilter_residual[ACB_SIZE], scratch, wcoef1, e->postfilter_fir, length); 600 601 /* Long term postfilter */ 602 best = idx; 603 for (i = FFMIN(MIN_DELAY, idx - 3); i <= FFMAX(MAX_DELAY, idx + 3); i++) { 604 for (n = ACB_SIZE, sum2 = 0; n < ACB_SIZE + length; n++) 605 sum2 += e->postfilter_residual[n] * e->postfilter_residual[n - i]; 606 if (sum2 > sum1) { 607 sum1 = sum2; 608 best = i; 609 } 610 } 611 612 for (i = ACB_SIZE, sum1 = 0; i < ACB_SIZE + length; i++) 613 sum1 += e->postfilter_residual[i - best] * e->postfilter_residual[i - best]; 614 for (i = ACB_SIZE, sum2 = 0; i < ACB_SIZE + length; i++) 615 sum2 += e->postfilter_residual[i] * e->postfilter_residual[i - best]; 616 617 if (sum2 * sum1 == 0 || e->bitrate == RATE_QUANT) { 618 memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float)); 619 } else { 620 gamma = sum2 / sum1; 621 if (gamma < 0.5) 622 memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float)); 623 else { 624 gamma = FFMIN(gamma, 1.0); 625 626 for (i = 0; i < length; i++) { 627 temp[i] = e->postfilter_residual[ACB_SIZE + i] + gamma * 628 pfc->ltgain * e->postfilter_residual[ACB_SIZE + i - best]; 629 } 630 } 631 } 632 633 memcpy(scratch, temp, length * sizeof(float)); 634 memcpy(mem, e->postfilter_iir, FILTER_ORDER * sizeof(float)); 635 synthesis_filter(scratch, wcoef2, mem, length, scratch); 636 637 /* Gain computation, TIA/IS-127 5.9.4-2 */ 638 for (i = 0, sum1 = 0, sum2 = 0; i < length; i++) { 639 sum1 += in[i] * in[i]; 640 sum2 += scratch[i] * scratch[i]; 641 } 642 gain = sum2 ? sqrt(sum1 / sum2) : 1.0; 643 644 for (i = 0; i < length; i++) 645 temp[i] *= gain; 646 647 /* Short term postfilter */ 648 synthesis_filter(temp, wcoef2, e->postfilter_iir, length, out); 649 650 memmove(e->postfilter_residual, 651 e->postfilter_residual + length, ACB_SIZE * sizeof(float)); 652} 653 654static void frame_erasure(EVRCContext *e, float *samples) 655{ 656 float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES], 657 tmp[SUBFRAME_SIZE + 6], f; 658 int i, j; 659 660 for (i = 0; i < FILTER_ORDER; i++) { 661 if (e->bitrate != RATE_QUANT) 662 e->lspf[i] = e->prev_lspf[i] * 0.875 + 0.125 * (i + 1) * 0.048; 663 else 664 e->lspf[i] = e->prev_lspf[i]; 665 } 666 667 if (e->prev_error_flag) 668 e->avg_acb_gain *= 0.75; 669 if (e->bitrate == RATE_FULL) 670 memcpy(e->pitch_back, e->pitch, ACB_SIZE * sizeof(float)); 671 if (e->last_valid_bitrate == RATE_QUANT) 672 e->bitrate = RATE_QUANT; 673 else 674 e->bitrate = RATE_FULL; 675 676 if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) { 677 e->pitch_delay = e->prev_pitch_delay; 678 } else { 679 float sum = 0; 680 681 idelay[0] = idelay[1] = idelay[2] = MIN_DELAY; 682 683 for (i = 0; i < NB_SUBFRAMES; i++) 684 sum += evrc_energy_quant[e->prev_energy_gain][i]; 685 sum /= (float) NB_SUBFRAMES; 686 sum = pow(10, sum); 687 for (i = 0; i < NB_SUBFRAMES; i++) 688 e->energy_vector[i] = sum; 689 } 690 691 if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15) 692 e->prev_pitch_delay = e->pitch_delay; 693 694 for (i = 0; i < NB_SUBFRAMES; i++) { 695 int subframe_size = subframe_sizes[i]; 696 int pitch_lag; 697 698 interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i); 699 700 if (e->bitrate != RATE_QUANT) { 701 if (e->avg_acb_gain < 0.3) { 702 idelay[0] = estimation_delay[i]; 703 idelay[1] = estimation_delay[i + 1]; 704 idelay[2] = estimation_delay[i + 2]; 705 } else { 706 interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i); 707 } 708 } 709 710 pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0); 711 decode_predictor_coeffs(ilspf, ilpc); 712 713 if (e->bitrate != RATE_QUANT) { 714 acb_excitation(e, e->pitch + ACB_SIZE, 715 e->avg_acb_gain, idelay, subframe_size); 716 for (j = 0; j < subframe_size; j++) 717 e->pitch[ACB_SIZE + j] *= e->fade_scale; 718 e->fade_scale = FFMAX(e->fade_scale - 0.05, 0.0); 719 } else { 720 for (j = 0; j < subframe_size; j++) 721 e->pitch[ACB_SIZE + j] = e->energy_vector[i]; 722 } 723 724 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float)); 725 726 if (e->bitrate != RATE_QUANT && e->avg_acb_gain < 0.4) { 727 f = 0.1 * e->avg_fcb_gain; 728 for (j = 0; j < subframe_size; j++) 729 e->pitch[ACB_SIZE + j] += f; 730 } else if (e->bitrate == RATE_QUANT) { 731 for (j = 0; j < subframe_size; j++) 732 e->pitch[ACB_SIZE + j] = e->energy_vector[i]; 733 } 734 735 synthesis_filter(e->pitch + ACB_SIZE, ilpc, 736 e->synthesis, subframe_size, tmp); 737 postfilter(e, tmp, ilpc, samples, pitch_lag, 738 &postfilter_coeffs[e->bitrate], subframe_size); 739 740 samples += subframe_size; 741 } 742} 743 744static int evrc_decode_frame(AVCodecContext *avctx, AVFrame *frame, 745 int *got_frame_ptr, AVPacket *avpkt) 746{ 747 const uint8_t *buf = avpkt->data; 748 EVRCContext *e = avctx->priv_data; 749 int buf_size = avpkt->size; 750 float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES]; 751 float *samples; 752 int i, j, ret, error_flag = 0; 753 754 frame->nb_samples = 160; 755 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) 756 return ret; 757 samples = (float *)frame->data[0]; 758 759 if ((e->bitrate = determine_bitrate(avctx, &buf_size, &buf)) == RATE_ERRS) { 760 warn_insufficient_frame_quality(avctx, "bitrate cannot be determined."); 761 goto erasure; 762 } 763 if (e->bitrate <= SILENCE || e->bitrate == RATE_QUARTER) 764 goto erasure; 765 if (e->bitrate == RATE_QUANT && e->last_valid_bitrate == RATE_FULL 766 && !e->prev_error_flag) 767 goto erasure; 768 769 if ((ret = init_get_bits8(&e->gb, buf, buf_size)) < 0) 770 return ret; 771 memset(&e->frame, 0, sizeof(EVRCAFrame)); 772 773 unpack_frame(e); 774 775 if (e->bitrate != RATE_QUANT) { 776 uint8_t *p = (uint8_t *) &e->frame; 777 for (i = 0; i < sizeof(EVRCAFrame); i++) { 778 if (p[i]) 779 break; 780 } 781 if (i == sizeof(EVRCAFrame)) 782 goto erasure; 783 } else if (e->frame.lsp[0] == 0xf && 784 e->frame.lsp[1] == 0xf && 785 e->frame.energy_gain == 0xff) { 786 goto erasure; 787 } 788 789 if (decode_lspf(e) < 0) 790 goto erasure; 791 792 if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) { 793 /* Pitch delay parameter checking as per TIA/IS-127 5.1.5.1 */ 794 if (e->frame.pitch_delay > MAX_DELAY - MIN_DELAY) 795 goto erasure; 796 797 e->pitch_delay = e->frame.pitch_delay + MIN_DELAY; 798 799 /* Delay diff parameter checking as per TIA/IS-127 5.1.5.2 */ 800 if (e->frame.delay_diff) { 801 int p = e->pitch_delay - e->frame.delay_diff + 16; 802 if (p < MIN_DELAY || p > MAX_DELAY) 803 goto erasure; 804 } 805 806 /* Delay contour reconstruction as per TIA/IS-127 5.2.2.2 */ 807 if (e->frame.delay_diff && 808 e->bitrate == RATE_FULL && e->prev_error_flag) { 809 float delay; 810 811 memcpy(e->pitch, e->pitch_back, ACB_SIZE * sizeof(float)); 812 813 delay = e->prev_pitch_delay; 814 e->prev_pitch_delay = delay - e->frame.delay_diff + 16.0; 815 816 if (fabs(e->pitch_delay - delay) > 15) 817 delay = e->pitch_delay; 818 819 for (i = 0; i < NB_SUBFRAMES; i++) { 820 int subframe_size = subframe_sizes[i]; 821 822 interpolate_delay(idelay, delay, e->prev_pitch_delay, i); 823 acb_excitation(e, e->pitch + ACB_SIZE, e->avg_acb_gain, idelay, subframe_size); 824 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float)); 825 } 826 } 827 828 /* Smoothing of the decoded delay as per TIA/IS-127 5.2.2.5 */ 829 if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15) 830 e->prev_pitch_delay = e->pitch_delay; 831 832 e->avg_acb_gain = e->avg_fcb_gain = 0.0; 833 } else { 834 idelay[0] = idelay[1] = idelay[2] = MIN_DELAY; 835 836 /* Decode frame energy vectors as per TIA/IS-127 5.7.2 */ 837 for (i = 0; i < NB_SUBFRAMES; i++) 838 e->energy_vector[i] = pow(10, evrc_energy_quant[e->frame.energy_gain][i]); 839 e->prev_energy_gain = e->frame.energy_gain; 840 } 841 842 for (i = 0; i < NB_SUBFRAMES; i++) { 843 float tmp[SUBFRAME_SIZE + 6] = { 0 }; 844 int subframe_size = subframe_sizes[i]; 845 int pitch_lag; 846 847 interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i); 848 849 if (e->bitrate != RATE_QUANT) 850 interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i); 851 852 pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0); 853 decode_predictor_coeffs(ilspf, ilpc); 854 855 /* Bandwidth expansion as per TIA/IS-127 5.2.3.3 */ 856 if (e->frame.lpc_flag && e->prev_error_flag) 857 bandwidth_expansion(ilpc, ilpc, 0.75); 858 859 if (e->bitrate != RATE_QUANT) { 860 float acb_sum, f; 861 862 f = exp((e->bitrate == RATE_HALF ? 0.5 : 0.25) 863 * (e->frame.fcb_gain[i] + 1)); 864 acb_sum = pitch_gain_vq[e->frame.acb_gain[i]]; 865 e->avg_acb_gain += acb_sum / NB_SUBFRAMES; 866 e->avg_fcb_gain += f / NB_SUBFRAMES; 867 868 acb_excitation(e, e->pitch + ACB_SIZE, 869 acb_sum, idelay, subframe_size); 870 fcb_excitation(e, e->frame.fcb_shape[i], tmp, 871 acb_sum, pitch_lag, subframe_size); 872 873 /* Total excitation generation as per TIA/IS-127 5.2.3.9 */ 874 for (j = 0; j < subframe_size; j++) 875 e->pitch[ACB_SIZE + j] += f * tmp[j]; 876 e->fade_scale = FFMIN(e->fade_scale + 0.2, 1.0); 877 } else { 878 for (j = 0; j < subframe_size; j++) 879 e->pitch[ACB_SIZE + j] = e->energy_vector[i]; 880 } 881 882 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float)); 883 884 synthesis_filter(e->pitch + ACB_SIZE, ilpc, 885 e->synthesis, subframe_size, 886 e->postfilter ? tmp : samples); 887 if (e->postfilter) 888 postfilter(e, tmp, ilpc, samples, pitch_lag, 889 &postfilter_coeffs[e->bitrate], subframe_size); 890 891 samples += subframe_size; 892 } 893 894 if (error_flag) { 895erasure: 896 error_flag = 1; 897 av_log(avctx, AV_LOG_WARNING, "frame erasure\n"); 898 frame_erasure(e, samples); 899 } 900 901 memcpy(e->prev_lspf, e->lspf, sizeof(e->prev_lspf)); 902 e->prev_error_flag = error_flag; 903 e->last_valid_bitrate = e->bitrate; 904 905 if (e->bitrate != RATE_QUANT) 906 e->prev_pitch_delay = e->pitch_delay; 907 908 samples = (float *)frame->data[0]; 909 for (i = 0; i < 160; i++) 910 samples[i] /= 32768; 911 912 *got_frame_ptr = 1; 913 914 return avpkt->size; 915} 916 917#define OFFSET(x) offsetof(EVRCContext, x) 918#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM 919 920static const AVOption options[] = { 921 { "postfilter", "enable postfilter", OFFSET(postfilter), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AD }, 922 { NULL } 923}; 924 925static const AVClass evrcdec_class = { 926 .class_name = "evrc", 927 .item_name = av_default_item_name, 928 .option = options, 929 .version = LIBAVUTIL_VERSION_INT, 930}; 931 932const FFCodec ff_evrc_decoder = { 933 .p.name = "evrc", 934 .p.long_name = NULL_IF_CONFIG_SMALL("EVRC (Enhanced Variable Rate Codec)"), 935 .p.type = AVMEDIA_TYPE_AUDIO, 936 .p.id = AV_CODEC_ID_EVRC, 937 .init = evrc_decode_init, 938 FF_CODEC_DECODE_CB(evrc_decode_frame), 939 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, 940 .priv_data_size = sizeof(EVRCContext), 941 .p.priv_class = &evrcdec_class, 942 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 943}; 944