1/* 2 * Real Audio 1.0 (14.4K) encoder 3 * Copyright (c) 2010 Francesco Lavra <francescolavra@interfree.it> 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 * Real Audio 1.0 (14.4K) encoder 25 * @author Francesco Lavra <francescolavra@interfree.it> 26 */ 27 28#include <float.h> 29 30#include "libavutil/channel_layout.h" 31#include "avcodec.h" 32#include "audio_frame_queue.h" 33#include "celp_filters.h" 34#include "codec_internal.h" 35#include "encode.h" 36#include "mathops.h" 37#include "put_bits.h" 38#include "ra144.h" 39 40static av_cold int ra144_encode_close(AVCodecContext *avctx) 41{ 42 RA144Context *ractx = avctx->priv_data; 43 ff_lpc_end(&ractx->lpc_ctx); 44 ff_af_queue_close(&ractx->afq); 45 return 0; 46} 47 48 49static av_cold int ra144_encode_init(AVCodecContext * avctx) 50{ 51 RA144Context *ractx; 52 int ret; 53 54 avctx->frame_size = NBLOCKS * BLOCKSIZE; 55 avctx->initial_padding = avctx->frame_size; 56 avctx->bit_rate = 8000; 57 ractx = avctx->priv_data; 58 ractx->lpc_coef[0] = ractx->lpc_tables[0]; 59 ractx->lpc_coef[1] = ractx->lpc_tables[1]; 60 ractx->avctx = avctx; 61 ff_audiodsp_init(&ractx->adsp); 62 ret = ff_lpc_init(&ractx->lpc_ctx, avctx->frame_size, LPC_ORDER, 63 FF_LPC_TYPE_LEVINSON); 64 if (ret < 0) 65 return ret; 66 67 ff_af_queue_init(avctx, &ractx->afq); 68 69 return 0; 70} 71 72 73/** 74 * Quantize a value by searching a sorted table for the element with the 75 * nearest value 76 * 77 * @param value value to quantize 78 * @param table array containing the quantization table 79 * @param size size of the quantization table 80 * @return index of the quantization table corresponding to the element with the 81 * nearest value 82 */ 83static int quantize(int value, const int16_t *table, unsigned int size) 84{ 85 unsigned int low = 0, high = size - 1; 86 87 while (1) { 88 int index = (low + high) >> 1; 89 int error = table[index] - value; 90 91 if (index == low) 92 return table[high] + error > value ? low : high; 93 if (error > 0) { 94 high = index; 95 } else { 96 low = index; 97 } 98 } 99} 100 101 102/** 103 * Orthogonalize a vector to another vector 104 * 105 * @param v vector to orthogonalize 106 * @param u vector against which orthogonalization is performed 107 */ 108static void orthogonalize(float *v, const float *u) 109{ 110 int i; 111 float num = 0, den = 0; 112 113 for (i = 0; i < BLOCKSIZE; i++) { 114 num += v[i] * u[i]; 115 den += u[i] * u[i]; 116 } 117 num /= den; 118 for (i = 0; i < BLOCKSIZE; i++) 119 v[i] -= num * u[i]; 120} 121 122 123/** 124 * Calculate match score and gain of an LPC-filtered vector with respect to 125 * input data, possibly orthogonalizing it to up to two other vectors. 126 * 127 * @param work array used to calculate the filtered vector 128 * @param coefs coefficients of the LPC filter 129 * @param vect original vector 130 * @param ortho1 first vector against which orthogonalization is performed 131 * @param ortho2 second vector against which orthogonalization is performed 132 * @param data input data 133 * @param score pointer to variable where match score is returned 134 * @param gain pointer to variable where gain is returned 135 */ 136static void get_match_score(float *work, const float *coefs, float *vect, 137 const float *ortho1, const float *ortho2, 138 const float *data, float *score, float *gain) 139{ 140 float c, g; 141 int i; 142 143 ff_celp_lp_synthesis_filterf(work, coefs, vect, BLOCKSIZE, LPC_ORDER); 144 if (ortho1) 145 orthogonalize(work, ortho1); 146 if (ortho2) 147 orthogonalize(work, ortho2); 148 c = g = 0; 149 for (i = 0; i < BLOCKSIZE; i++) { 150 g += work[i] * work[i]; 151 c += data[i] * work[i]; 152 } 153 if (c <= 0) { 154 *score = 0; 155 return; 156 } 157 *gain = c / g; 158 *score = *gain * c; 159} 160 161 162/** 163 * Create a vector from the adaptive codebook at a given lag value 164 * 165 * @param vect array where vector is stored 166 * @param cb adaptive codebook 167 * @param lag lag value 168 */ 169static void create_adapt_vect(float *vect, const int16_t *cb, int lag) 170{ 171 int i; 172 173 cb += BUFFERSIZE - lag; 174 for (i = 0; i < FFMIN(BLOCKSIZE, lag); i++) 175 vect[i] = cb[i]; 176 if (lag < BLOCKSIZE) 177 for (i = 0; i < BLOCKSIZE - lag; i++) 178 vect[lag + i] = cb[i]; 179} 180 181 182/** 183 * Search the adaptive codebook for the best entry and gain and remove its 184 * contribution from input data 185 * 186 * @param adapt_cb array from which the adaptive codebook is extracted 187 * @param work array used to calculate LPC-filtered vectors 188 * @param coefs coefficients of the LPC filter 189 * @param data input data 190 * @return index of the best entry of the adaptive codebook 191 */ 192static int adaptive_cb_search(const int16_t *adapt_cb, float *work, 193 const float *coefs, float *data) 194{ 195 int i, av_uninit(best_vect); 196 float score, gain, best_score, av_uninit(best_gain); 197 float exc[BLOCKSIZE]; 198 199 gain = best_score = 0; 200 for (i = BLOCKSIZE / 2; i <= BUFFERSIZE; i++) { 201 create_adapt_vect(exc, adapt_cb, i); 202 get_match_score(work, coefs, exc, NULL, NULL, data, &score, &gain); 203 if (score > best_score) { 204 best_score = score; 205 best_vect = i; 206 best_gain = gain; 207 } 208 } 209 if (!best_score) 210 return 0; 211 212 /** 213 * Re-calculate the filtered vector from the vector with maximum match score 214 * and remove its contribution from input data. 215 */ 216 create_adapt_vect(exc, adapt_cb, best_vect); 217 ff_celp_lp_synthesis_filterf(work, coefs, exc, BLOCKSIZE, LPC_ORDER); 218 for (i = 0; i < BLOCKSIZE; i++) 219 data[i] -= best_gain * work[i]; 220 return best_vect - BLOCKSIZE / 2 + 1; 221} 222 223 224/** 225 * Find the best vector of a fixed codebook by applying an LPC filter to 226 * codebook entries, possibly orthogonalizing them to up to two other vectors 227 * and matching the results with input data. 228 * 229 * @param work array used to calculate the filtered vectors 230 * @param coefs coefficients of the LPC filter 231 * @param cb fixed codebook 232 * @param ortho1 first vector against which orthogonalization is performed 233 * @param ortho2 second vector against which orthogonalization is performed 234 * @param data input data 235 * @param idx pointer to variable where the index of the best codebook entry is 236 * returned 237 * @param gain pointer to variable where the gain of the best codebook entry is 238 * returned 239 */ 240static void find_best_vect(float *work, const float *coefs, 241 const int8_t cb[][BLOCKSIZE], const float *ortho1, 242 const float *ortho2, float *data, int *idx, 243 float *gain) 244{ 245 int i, j; 246 float g, score, best_score; 247 float vect[BLOCKSIZE]; 248 249 *idx = *gain = best_score = 0; 250 for (i = 0; i < FIXED_CB_SIZE; i++) { 251 for (j = 0; j < BLOCKSIZE; j++) 252 vect[j] = cb[i][j]; 253 get_match_score(work, coefs, vect, ortho1, ortho2, data, &score, &g); 254 if (score > best_score) { 255 best_score = score; 256 *idx = i; 257 *gain = g; 258 } 259 } 260} 261 262 263/** 264 * Search the two fixed codebooks for the best entry and gain 265 * 266 * @param work array used to calculate LPC-filtered vectors 267 * @param coefs coefficients of the LPC filter 268 * @param data input data 269 * @param cba_idx index of the best entry of the adaptive codebook 270 * @param cb1_idx pointer to variable where the index of the best entry of the 271 * first fixed codebook is returned 272 * @param cb2_idx pointer to variable where the index of the best entry of the 273 * second fixed codebook is returned 274 */ 275static void fixed_cb_search(float *work, const float *coefs, float *data, 276 int cba_idx, int *cb1_idx, int *cb2_idx) 277{ 278 int i, ortho_cb1; 279 float gain; 280 float cba_vect[BLOCKSIZE], cb1_vect[BLOCKSIZE]; 281 float vect[BLOCKSIZE]; 282 283 /** 284 * The filtered vector from the adaptive codebook can be retrieved from 285 * work, because this function is called just after adaptive_cb_search(). 286 */ 287 if (cba_idx) 288 memcpy(cba_vect, work, sizeof(cba_vect)); 289 290 find_best_vect(work, coefs, ff_cb1_vects, cba_idx ? cba_vect : NULL, NULL, 291 data, cb1_idx, &gain); 292 293 /** 294 * Re-calculate the filtered vector from the vector with maximum match score 295 * and remove its contribution from input data. 296 */ 297 if (gain) { 298 for (i = 0; i < BLOCKSIZE; i++) 299 vect[i] = ff_cb1_vects[*cb1_idx][i]; 300 ff_celp_lp_synthesis_filterf(work, coefs, vect, BLOCKSIZE, LPC_ORDER); 301 if (cba_idx) 302 orthogonalize(work, cba_vect); 303 for (i = 0; i < BLOCKSIZE; i++) 304 data[i] -= gain * work[i]; 305 memcpy(cb1_vect, work, sizeof(cb1_vect)); 306 ortho_cb1 = 1; 307 } else 308 ortho_cb1 = 0; 309 310 find_best_vect(work, coefs, ff_cb2_vects, cba_idx ? cba_vect : NULL, 311 ortho_cb1 ? cb1_vect : NULL, data, cb2_idx, &gain); 312} 313 314 315/** 316 * Encode a subblock of the current frame 317 * 318 * @param ractx encoder context 319 * @param sblock_data input data of the subblock 320 * @param lpc_coefs coefficients of the LPC filter 321 * @param rms RMS of the reflection coefficients 322 * @param pb pointer to PutBitContext of the current frame 323 */ 324static void ra144_encode_subblock(RA144Context *ractx, 325 const int16_t *sblock_data, 326 const int16_t *lpc_coefs, unsigned int rms, 327 PutBitContext *pb) 328{ 329 float data[BLOCKSIZE] = { 0 }, work[LPC_ORDER + BLOCKSIZE]; 330 float coefs[LPC_ORDER]; 331 float zero[BLOCKSIZE], cba[BLOCKSIZE], cb1[BLOCKSIZE], cb2[BLOCKSIZE]; 332 int cba_idx, cb1_idx, cb2_idx, gain; 333 int i, n; 334 unsigned m[3]; 335 float g[3]; 336 float error, best_error; 337 338 for (i = 0; i < LPC_ORDER; i++) { 339 work[i] = ractx->curr_sblock[BLOCKSIZE + i]; 340 coefs[i] = lpc_coefs[i] * (1/4096.0); 341 } 342 343 /** 344 * Calculate the zero-input response of the LPC filter and subtract it from 345 * input data. 346 */ 347 ff_celp_lp_synthesis_filterf(work + LPC_ORDER, coefs, data, BLOCKSIZE, 348 LPC_ORDER); 349 for (i = 0; i < BLOCKSIZE; i++) { 350 zero[i] = work[LPC_ORDER + i]; 351 data[i] = sblock_data[i] - zero[i]; 352 } 353 354 /** 355 * Codebook search is performed without taking into account the contribution 356 * of the previous subblock, since it has been just subtracted from input 357 * data. 358 */ 359 memset(work, 0, LPC_ORDER * sizeof(*work)); 360 361 cba_idx = adaptive_cb_search(ractx->adapt_cb, work + LPC_ORDER, coefs, 362 data); 363 if (cba_idx) { 364 /** 365 * The filtered vector from the adaptive codebook can be retrieved from 366 * work, see implementation of adaptive_cb_search(). 367 */ 368 memcpy(cba, work + LPC_ORDER, sizeof(cba)); 369 370 ff_copy_and_dup(ractx->buffer_a, ractx->adapt_cb, cba_idx + BLOCKSIZE / 2 - 1); 371 m[0] = (ff_irms(&ractx->adsp, ractx->buffer_a) * rms) >> 12; 372 } 373 fixed_cb_search(work + LPC_ORDER, coefs, data, cba_idx, &cb1_idx, &cb2_idx); 374 for (i = 0; i < BLOCKSIZE; i++) { 375 cb1[i] = ff_cb1_vects[cb1_idx][i]; 376 cb2[i] = ff_cb2_vects[cb2_idx][i]; 377 } 378 ff_celp_lp_synthesis_filterf(work + LPC_ORDER, coefs, cb1, BLOCKSIZE, 379 LPC_ORDER); 380 memcpy(cb1, work + LPC_ORDER, sizeof(cb1)); 381 m[1] = (ff_cb1_base[cb1_idx] * rms) >> 8; 382 ff_celp_lp_synthesis_filterf(work + LPC_ORDER, coefs, cb2, BLOCKSIZE, 383 LPC_ORDER); 384 memcpy(cb2, work + LPC_ORDER, sizeof(cb2)); 385 m[2] = (ff_cb2_base[cb2_idx] * rms) >> 8; 386 best_error = FLT_MAX; 387 gain = 0; 388 for (n = 0; n < 256; n++) { 389 g[1] = ((ff_gain_val_tab[n][1] * m[1]) >> ff_gain_exp_tab[n]) * 390 (1/4096.0); 391 g[2] = ((ff_gain_val_tab[n][2] * m[2]) >> ff_gain_exp_tab[n]) * 392 (1/4096.0); 393 error = 0; 394 if (cba_idx) { 395 g[0] = ((ff_gain_val_tab[n][0] * m[0]) >> ff_gain_exp_tab[n]) * 396 (1/4096.0); 397 for (i = 0; i < BLOCKSIZE; i++) { 398 data[i] = zero[i] + g[0] * cba[i] + g[1] * cb1[i] + 399 g[2] * cb2[i]; 400 error += (data[i] - sblock_data[i]) * 401 (data[i] - sblock_data[i]); 402 } 403 } else { 404 for (i = 0; i < BLOCKSIZE; i++) { 405 data[i] = zero[i] + g[1] * cb1[i] + g[2] * cb2[i]; 406 error += (data[i] - sblock_data[i]) * 407 (data[i] - sblock_data[i]); 408 } 409 } 410 if (error < best_error) { 411 best_error = error; 412 gain = n; 413 } 414 } 415 put_bits(pb, 7, cba_idx); 416 put_bits(pb, 8, gain); 417 put_bits(pb, 7, cb1_idx); 418 put_bits(pb, 7, cb2_idx); 419 ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, rms, 420 gain); 421} 422 423 424static int ra144_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, 425 const AVFrame *frame, int *got_packet_ptr) 426{ 427 static const uint8_t sizes[LPC_ORDER] = {64, 32, 32, 16, 16, 8, 8, 8, 8, 4}; 428 static const uint8_t bit_sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; 429 RA144Context *ractx = avctx->priv_data; 430 PutBitContext pb; 431 int32_t lpc_data[NBLOCKS * BLOCKSIZE]; 432 int32_t lpc_coefs[LPC_ORDER][MAX_LPC_ORDER]; 433 int shift[LPC_ORDER]; 434 int16_t block_coefs[NBLOCKS][LPC_ORDER]; 435 int lpc_refl[LPC_ORDER]; /**< reflection coefficients of the frame */ 436 unsigned int refl_rms[NBLOCKS]; /**< RMS of the reflection coefficients */ 437 const int16_t *samples = frame ? (const int16_t *)frame->data[0] : NULL; 438 int energy = 0; 439 int i, idx, ret; 440 441 if (ractx->last_frame) 442 return 0; 443 444 if ((ret = ff_get_encode_buffer(avctx, avpkt, FRAME_SIZE, 0)) < 0) 445 return ret; 446 447 /** 448 * Since the LPC coefficients are calculated on a frame centered over the 449 * fourth subframe, to encode a given frame, data from the next frame is 450 * needed. In each call to this function, the previous frame (whose data are 451 * saved in the encoder context) is encoded, and data from the current frame 452 * are saved in the encoder context to be used in the next function call. 453 */ 454 for (i = 0; i < (2 * BLOCKSIZE + BLOCKSIZE / 2); i++) { 455 lpc_data[i] = ractx->curr_block[BLOCKSIZE + BLOCKSIZE / 2 + i]; 456 energy += (lpc_data[i] * lpc_data[i]) >> 4; 457 } 458 if (frame) { 459 int j; 460 for (j = 0; j < frame->nb_samples && i < NBLOCKS * BLOCKSIZE; i++, j++) { 461 lpc_data[i] = samples[j] >> 2; 462 energy += (lpc_data[i] * lpc_data[i]) >> 4; 463 } 464 } 465 if (i < NBLOCKS * BLOCKSIZE) 466 memset(&lpc_data[i], 0, (NBLOCKS * BLOCKSIZE - i) * sizeof(*lpc_data)); 467 energy = ff_energy_tab[quantize(ff_t_sqrt(energy >> 5) >> 10, ff_energy_tab, 468 32)]; 469 470 ff_lpc_calc_coefs(&ractx->lpc_ctx, lpc_data, NBLOCKS * BLOCKSIZE, LPC_ORDER, 471 LPC_ORDER, 16, lpc_coefs, shift, FF_LPC_TYPE_LEVINSON, 472 0, ORDER_METHOD_EST, 0, 12, 0); 473 for (i = 0; i < LPC_ORDER; i++) 474 block_coefs[NBLOCKS - 1][i] = -lpc_coefs[LPC_ORDER - 1][i] 475 * (1 << (12 - shift[LPC_ORDER - 1])); 476 477 /** 478 * TODO: apply perceptual weighting of the input speech through bandwidth 479 * expansion of the LPC filter. 480 */ 481 482 if (ff_eval_refl(lpc_refl, block_coefs[NBLOCKS - 1], avctx)) { 483 /** 484 * The filter is unstable: use the coefficients of the previous frame. 485 */ 486 ff_int_to_int16(block_coefs[NBLOCKS - 1], ractx->lpc_coef[1]); 487 if (ff_eval_refl(lpc_refl, block_coefs[NBLOCKS - 1], avctx)) { 488 /* the filter is still unstable. set reflection coeffs to zero. */ 489 memset(lpc_refl, 0, sizeof(lpc_refl)); 490 } 491 } 492 init_put_bits(&pb, avpkt->data, avpkt->size); 493 for (i = 0; i < LPC_ORDER; i++) { 494 idx = quantize(lpc_refl[i], ff_lpc_refl_cb[i], sizes[i]); 495 put_bits(&pb, bit_sizes[i], idx); 496 lpc_refl[i] = ff_lpc_refl_cb[i][idx]; 497 } 498 ractx->lpc_refl_rms[0] = ff_rms(lpc_refl); 499 ff_eval_coefs(ractx->lpc_coef[0], lpc_refl); 500 refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy); 501 refl_rms[1] = ff_interp(ractx, block_coefs[1], 2, 502 energy <= ractx->old_energy, 503 ff_t_sqrt(energy * ractx->old_energy) >> 12); 504 refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy); 505 refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy); 506 ff_int_to_int16(block_coefs[NBLOCKS - 1], ractx->lpc_coef[0]); 507 put_bits(&pb, 5, quantize(energy, ff_energy_tab, 32)); 508 for (i = 0; i < NBLOCKS; i++) 509 ra144_encode_subblock(ractx, ractx->curr_block + i * BLOCKSIZE, 510 block_coefs[i], refl_rms[i], &pb); 511 flush_put_bits(&pb); 512 ractx->old_energy = energy; 513 ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0]; 514 FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]); 515 516 /* copy input samples to current block for processing in next call */ 517 i = 0; 518 if (frame) { 519 for (; i < frame->nb_samples; i++) 520 ractx->curr_block[i] = samples[i] >> 2; 521 522 if ((ret = ff_af_queue_add(&ractx->afq, frame)) < 0) 523 return ret; 524 } else 525 ractx->last_frame = 1; 526 memset(&ractx->curr_block[i], 0, 527 (NBLOCKS * BLOCKSIZE - i) * sizeof(*ractx->curr_block)); 528 529 /* Get the next frame pts/duration */ 530 ff_af_queue_remove(&ractx->afq, avctx->frame_size, &avpkt->pts, 531 &avpkt->duration); 532 533 *got_packet_ptr = 1; 534 return 0; 535} 536 537 538const FFCodec ff_ra_144_encoder = { 539 .p.name = "real_144", 540 .p.long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"), 541 .p.type = AVMEDIA_TYPE_AUDIO, 542 .p.id = AV_CODEC_ID_RA_144, 543 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY | 544 AV_CODEC_CAP_SMALL_LAST_FRAME, 545 .priv_data_size = sizeof(RA144Context), 546 .init = ra144_encode_init, 547 FF_CODEC_ENCODE_CB(ra144_encode_frame), 548 .close = ra144_encode_close, 549 .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, 550 AV_SAMPLE_FMT_NONE }, 551 .p.supported_samplerates = (const int[]){ 8000, 0 }, 552#if FF_API_OLD_CHANNEL_LAYOUT 553 .p.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO, 0 }, 554#endif 555 .p.ch_layouts = (const AVChannelLayout[]){ AV_CHANNEL_LAYOUT_MONO, { 0 } }, 556 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 557}; 558