libavcodec/ra144enc.c

   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
  40 static 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
  49 static 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  */
  83 static 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  */
 108 static 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  */
 136 static 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  */
 169 static 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  */
 192 static 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  */
 240 static 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  */
 275 static 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  */
 324 static 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
 424 static 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
 538 const FFCodec ff_ra_144_encoder = {
 539     .p.name         = "real_144",
 540     CODEC_LONG_NAME("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     .p.ch_layouts   = (const AVChannelLayout[]){ AV_CHANNEL_LAYOUT_MONO, { 0 } },
 553 };