libavcodec/sipr.c

   1 /*
   2  * SIPR / ACELP.NET decoder
   3  *
   4  * Copyright (c) 2008 Vladimir Voroshilov
   5  * Copyright (c) 2009 Vitor Sessak
   6  *
   7  * This file is part of Libav.
   8  *
   9  * Libav is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * Libav is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with Libav; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include <math.h>
  25 #include <stdint.h>
  26 #include <string.h>
  27
  28 #include "libavutil/channel_layout.h"
  29 #include "libavutil/float_dsp.h"
  30 #include "libavutil/mathematics.h"
  31 #include "avcodec.h"
  32 #define BITSTREAM_READER_LE
  33 #include "get_bits.h"
  34 #include "internal.h"
  35
  36 #include "lsp.h"
  37 #include "acelp_vectors.h"
  38 #include "acelp_pitch_delay.h"
  39 #include "acelp_filters.h"
  40 #include "celp_filters.h"
  41
  42 #define MAX_SUBFRAME_COUNT   5
  43
  44 #include "sipr.h"
  45 #include "siprdata.h"
  46
  47 typedef struct {
  48     const char *mode_name;
  49     uint16_t bits_per_frame;
  50     uint8_t subframe_count;
  51     uint8_t frames_per_packet;
  52     float pitch_sharp_factor;
  53
  54     /* bitstream parameters */
  55     uint8_t number_of_fc_indexes;
  56     uint8_t ma_predictor_bits;  ///< size in bits of the switched MA predictor
  57
  58     /** size in bits of the i-th stage vector of quantizer */
  59     uint8_t vq_indexes_bits[5];
  60
  61     /** size in bits of the adaptive-codebook index for every subframe */
  62     uint8_t pitch_delay_bits[5];
  63
  64     uint8_t gp_index_bits;
  65     uint8_t fc_index_bits[10]; ///< size in bits of the fixed codebook indexes
  66     uint8_t gc_index_bits;     ///< size in bits of the gain  codebook indexes
  67 } SiprModeParam;
  68
  69 static const SiprModeParam modes[MODE_COUNT] = {
  70     [MODE_16k] = {
  71         .mode_name          = "16k",
  72         .bits_per_frame     = 160,
  73         .subframe_count     = SUBFRAME_COUNT_16k,
  74         .frames_per_packet  = 1,
  75         .pitch_sharp_factor = 0.00,
  76
  77         .number_of_fc_indexes = 10,
  78         .ma_predictor_bits    = 1,
  79         .vq_indexes_bits      = {7, 8, 7, 7, 7},
  80         .pitch_delay_bits     = {9, 6},
  81         .gp_index_bits        = 4,
  82         .fc_index_bits        = {4, 5, 4, 5, 4, 5, 4, 5, 4, 5},
  83         .gc_index_bits        = 5
  84     },
  85
  86     [MODE_8k5] = {
  87         .mode_name          = "8k5",
  88         .bits_per_frame     = 152,
  89         .subframe_count     = 3,
  90         .frames_per_packet  = 1,
  91         .pitch_sharp_factor = 0.8,
  92
  93         .number_of_fc_indexes = 3,
  94         .ma_predictor_bits    = 0,
  95         .vq_indexes_bits      = {6, 7, 7, 7, 5},
  96         .pitch_delay_bits     = {8, 5, 5},
  97         .gp_index_bits        = 0,
  98         .fc_index_bits        = {9, 9, 9},
  99         .gc_index_bits        = 7
 100     },
 101
 102     [MODE_6k5] = {
 103         .mode_name          = "6k5",
 104         .bits_per_frame     = 232,
 105         .subframe_count     = 3,
 106         .frames_per_packet  = 2,
 107         .pitch_sharp_factor = 0.8,
 108
 109         .number_of_fc_indexes = 3,
 110         .ma_predictor_bits    = 0,
 111         .vq_indexes_bits      = {6, 7, 7, 7, 5},
 112         .pitch_delay_bits     = {8, 5, 5},
 113         .gp_index_bits        = 0,
 114         .fc_index_bits        = {5, 5, 5},
 115         .gc_index_bits        = 7
 116     },
 117
 118     [MODE_5k0] = {
 119         .mode_name          = "5k0",
 120         .bits_per_frame     = 296,
 121         .subframe_count     = 5,
 122         .frames_per_packet  = 2,
 123         .pitch_sharp_factor = 0.85,
 124
 125         .number_of_fc_indexes = 1,
 126         .ma_predictor_bits    = 0,
 127         .vq_indexes_bits      = {6, 7, 7, 7, 5},
 128         .pitch_delay_bits     = {8, 5, 8, 5, 5},
 129         .gp_index_bits        = 0,
 130         .fc_index_bits        = {10},
 131         .gc_index_bits        = 7
 132     }
 133 };
 134
 135 const float ff_pow_0_5[] = {
 136     1.0/(1 <<  1), 1.0/(1 <<  2), 1.0/(1 <<  3), 1.0/(1 <<  4),
 137     1.0/(1 <<  5), 1.0/(1 <<  6), 1.0/(1 <<  7), 1.0/(1 <<  8),
 138     1.0/(1 <<  9), 1.0/(1 << 10), 1.0/(1 << 11), 1.0/(1 << 12),
 139     1.0/(1 << 13), 1.0/(1 << 14), 1.0/(1 << 15), 1.0/(1 << 16)
 140 };
 141
 142 static void dequant(float *out, const int *idx, const float *cbs[])
 143 {
 144     int i;
 145     int stride  = 2;
 146     int num_vec = 5;
 147
 148     for (i = 0; i < num_vec; i++)
 149         memcpy(out + stride*i, cbs[i] + stride*idx[i], stride*sizeof(float));
 150
 151 }
 152
 153 static void lsf_decode_fp(float *lsfnew, float *lsf_history,
 154                           const SiprParameters *parm)
 155 {
 156     int i;
 157     float lsf_tmp[LP_FILTER_ORDER];
 158
 159     dequant(lsf_tmp, parm->vq_indexes, lsf_codebooks);
 160
 161     for (i = 0; i < LP_FILTER_ORDER; i++)
 162         lsfnew[i] = lsf_history[i] * 0.33 + lsf_tmp[i] + mean_lsf[i];
 163
 164     ff_sort_nearly_sorted_floats(lsfnew, LP_FILTER_ORDER - 1);
 165
 166     /* Note that a minimum distance is not enforced between the last value and
 167        the previous one, contrary to what is done in ff_acelp_reorder_lsf() */
 168     ff_set_min_dist_lsf(lsfnew, LSFQ_DIFF_MIN, LP_FILTER_ORDER - 1);
 169     lsfnew[9] = FFMIN(lsfnew[LP_FILTER_ORDER - 1], 1.3 * M_PI);
 170
 171     memcpy(lsf_history, lsf_tmp, LP_FILTER_ORDER * sizeof(*lsf_history));
 172
 173     for (i = 0; i < LP_FILTER_ORDER - 1; i++)
 174         lsfnew[i] = cos(lsfnew[i]);
 175     lsfnew[LP_FILTER_ORDER - 1] *= 6.153848 / M_PI;
 176 }
 177
 178 /** Apply pitch lag to the fixed vector (AMR section 6.1.2). */
 179 static void pitch_sharpening(int pitch_lag_int, float beta,
 180                              float *fixed_vector)
 181 {
 182     int i;
 183
 184     for (i = pitch_lag_int; i < SUBFR_SIZE; i++)
 185         fixed_vector[i] += beta * fixed_vector[i - pitch_lag_int];
 186 }
 187
 188 /**
 189  * Extract decoding parameters from the input bitstream.
 190  * @param parms          parameters structure
 191  * @param pgb            pointer to initialized GetBitContext structure
 192  */
 193 static void decode_parameters(SiprParameters* parms, GetBitContext *pgb,
 194                               const SiprModeParam *p)
 195 {
 196     int i, j;
 197
 198     if (p->ma_predictor_bits)
 199         parms->ma_pred_switch       = get_bits(pgb, p->ma_predictor_bits);
 200
 201     for (i = 0; i < 5; i++)
 202         parms->vq_indexes[i]        = get_bits(pgb, p->vq_indexes_bits[i]);
 203
 204     for (i = 0; i < p->subframe_count; i++) {
 205         parms->pitch_delay[i]       = get_bits(pgb, p->pitch_delay_bits[i]);
 206         if (p->gp_index_bits)
 207             parms->gp_index[i]      = get_bits(pgb, p->gp_index_bits);
 208
 209         for (j = 0; j < p->number_of_fc_indexes; j++)
 210             parms->fc_indexes[i][j] = get_bits(pgb, p->fc_index_bits[j]);
 211
 212         parms->gc_index[i]          = get_bits(pgb, p->gc_index_bits);
 213     }
 214 }
 215
 216 static void sipr_decode_lp(float *lsfnew, const float *lsfold, float *Az,
 217                            int num_subfr)
 218 {
 219     double lsfint[LP_FILTER_ORDER];
 220     int i,j;
 221     float t, t0 = 1.0 / num_subfr;
 222
 223     t = t0 * 0.5;
 224     for (i = 0; i < num_subfr; i++) {
 225         for (j = 0; j < LP_FILTER_ORDER; j++)
 226             lsfint[j] = lsfold[j] * (1 - t) + t * lsfnew[j];
 227
 228         ff_amrwb_lsp2lpc(lsfint, Az, LP_FILTER_ORDER);
 229         Az += LP_FILTER_ORDER;
 230         t += t0;
 231     }
 232 }
 233
 234 /**
 235  * Evaluate the adaptive impulse response.
 236  */
 237 static void eval_ir(const float *Az, int pitch_lag, float *freq,
 238                     float pitch_sharp_factor)
 239 {
 240     float tmp1[SUBFR_SIZE+1], tmp2[LP_FILTER_ORDER+1];
 241     int i;
 242
 243     tmp1[0] = 1.;
 244     for (i = 0; i < LP_FILTER_ORDER; i++) {
 245         tmp1[i+1] = Az[i] * ff_pow_0_55[i];
 246         tmp2[i  ] = Az[i] * ff_pow_0_7 [i];
 247     }
 248     memset(tmp1 + 11, 0, 37 * sizeof(float));
 249
 250     ff_celp_lp_synthesis_filterf(freq, tmp2, tmp1, SUBFR_SIZE,
 251                                  LP_FILTER_ORDER);
 252
 253     pitch_sharpening(pitch_lag, pitch_sharp_factor, freq);
 254 }
 255
 256 /**
 257  * Evaluate the convolution of a vector with a sparse vector.
 258  */
 259 static void convolute_with_sparse(float *out, const AMRFixed *pulses,
 260                                   const float *shape, int length)
 261 {
 262     int i, j;
 263
 264     memset(out, 0, length*sizeof(float));
 265     for (i = 0; i < pulses->n; i++)
 266         for (j = pulses->x[i]; j < length; j++)
 267             out[j] += pulses->y[i] * shape[j - pulses->x[i]];
 268 }
 269
 270 /**
 271  * Apply postfilter, very similar to AMR one.
 272  */
 273 static void postfilter_5k0(SiprContext *ctx, const float *lpc, float *samples)
 274 {
 275     float buf[SUBFR_SIZE + LP_FILTER_ORDER];
 276     float *pole_out = buf + LP_FILTER_ORDER;
 277     float lpc_n[LP_FILTER_ORDER];
 278     float lpc_d[LP_FILTER_ORDER];
 279     int i;
 280
 281     for (i = 0; i < LP_FILTER_ORDER; i++) {
 282         lpc_d[i] = lpc[i] * ff_pow_0_75[i];
 283         lpc_n[i] = lpc[i] * ff_pow_0_5 [i];
 284     };
 285
 286     memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem,
 287            LP_FILTER_ORDER*sizeof(float));
 288
 289     ff_celp_lp_synthesis_filterf(pole_out, lpc_d, samples, SUBFR_SIZE,
 290                                  LP_FILTER_ORDER);
 291
 292     memcpy(ctx->postfilter_mem, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,
 293            LP_FILTER_ORDER*sizeof(float));
 294
 295     ff_tilt_compensation(&ctx->tilt_mem, 0.4, pole_out, SUBFR_SIZE);
 296
 297     memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem5k0,
 298            LP_FILTER_ORDER*sizeof(*pole_out));
 299
 300     memcpy(ctx->postfilter_mem5k0, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,
 301            LP_FILTER_ORDER*sizeof(*pole_out));
 302
 303     ff_celp_lp_zero_synthesis_filterf(samples, lpc_n, pole_out, SUBFR_SIZE,
 304                                       LP_FILTER_ORDER);
 305
 306 }
 307
 308 static void decode_fixed_sparse(AMRFixed *fixed_sparse, const int16_t *pulses,
 309                                 SiprMode mode, int low_gain)
 310 {
 311     int i;
 312
 313     switch (mode) {
 314     case MODE_6k5:
 315         for (i = 0; i < 3; i++) {
 316             fixed_sparse->x[i] = 3 * (pulses[i] & 0xf) + i;
 317             fixed_sparse->y[i] = pulses[i] & 0x10 ? -1 : 1;
 318         }
 319         fixed_sparse->n = 3;
 320         break;
 321     case MODE_8k5:
 322         for (i = 0; i < 3; i++) {
 323             fixed_sparse->x[2*i    ] = 3 * ((pulses[i] >> 4) & 0xf) + i;
 324             fixed_sparse->x[2*i + 1] = 3 * ( pulses[i]       & 0xf) + i;
 325
 326             fixed_sparse->y[2*i    ] = (pulses[i] & 0x100) ? -1.0: 1.0;
 327
 328             fixed_sparse->y[2*i + 1] =
 329                 (fixed_sparse->x[2*i + 1] < fixed_sparse->x[2*i]) ?
 330                 -fixed_sparse->y[2*i    ] : fixed_sparse->y[2*i];
 331         }
 332
 333         fixed_sparse->n = 6;
 334         break;
 335     case MODE_5k0:
 336     default:
 337         if (low_gain) {
 338             int offset = (pulses[0] & 0x200) ? 2 : 0;
 339             int val = pulses[0];
 340
 341             for (i = 0; i < 3; i++) {
 342                 int index = (val & 0x7) * 6 + 4 - i*2;
 343
 344                 fixed_sparse->y[i] = (offset + index) & 0x3 ? -1 : 1;
 345                 fixed_sparse->x[i] = index;
 346
 347                 val >>= 3;
 348             }
 349             fixed_sparse->n = 3;
 350         } else {
 351             int pulse_subset = (pulses[0] >> 8) & 1;
 352
 353             fixed_sparse->x[0] = ((pulses[0] >> 4) & 15) * 3 + pulse_subset;
 354             fixed_sparse->x[1] = ( pulses[0]       & 15) * 3 + pulse_subset + 1;
 355
 356             fixed_sparse->y[0] = pulses[0] & 0x200 ? -1 : 1;
 357             fixed_sparse->y[1] = -fixed_sparse->y[0];
 358             fixed_sparse->n = 2;
 359         }
 360         break;
 361     }
 362 }
 363
 364 static void decode_frame(SiprContext *ctx, SiprParameters *params,
 365                          float *out_data)
 366 {
 367     int i, j;
 368     int subframe_count = modes[ctx->mode].subframe_count;
 369     int frame_size = subframe_count * SUBFR_SIZE;
 370     float Az[LP_FILTER_ORDER * MAX_SUBFRAME_COUNT];
 371     float *excitation;
 372     float ir_buf[SUBFR_SIZE + LP_FILTER_ORDER];
 373     float lsf_new[LP_FILTER_ORDER];
 374     float *impulse_response = ir_buf + LP_FILTER_ORDER;
 375     float *synth = ctx->synth_buf + 16; // 16 instead of LP_FILTER_ORDER for
 376                                         // memory alignment
 377     int t0_first = 0;
 378     AMRFixed fixed_cb;
 379
 380     memset(ir_buf, 0, LP_FILTER_ORDER * sizeof(float));
 381     lsf_decode_fp(lsf_new, ctx->lsf_history, params);
 382
 383     sipr_decode_lp(lsf_new, ctx->lsp_history, Az, subframe_count);
 384
 385     memcpy(ctx->lsp_history, lsf_new, LP_FILTER_ORDER * sizeof(float));
 386
 387     excitation = ctx->excitation + PITCH_DELAY_MAX + L_INTERPOL;
 388
 389     for (i = 0; i < subframe_count; i++) {
 390         float *pAz = Az + i*LP_FILTER_ORDER;
 391         float fixed_vector[SUBFR_SIZE];
 392         int T0,T0_frac;
 393         float pitch_gain, gain_code, avg_energy;
 394
 395         ff_decode_pitch_lag(&T0, &T0_frac, params->pitch_delay[i], t0_first, i,
 396                             ctx->mode == MODE_5k0, 6);
 397
 398         if (i == 0 || (i == 2 && ctx->mode == MODE_5k0))
 399             t0_first = T0;
 400
 401         ff_acelp_interpolatef(excitation, excitation - T0 + (T0_frac <= 0),
 402                               ff_b60_sinc, 6,
 403                               2 * ((2 + T0_frac)%3 + 1), LP_FILTER_ORDER,
 404                               SUBFR_SIZE);
 405
 406         decode_fixed_sparse(&fixed_cb, params->fc_indexes[i], ctx->mode,
 407                             ctx->past_pitch_gain < 0.8);
 408
 409         eval_ir(pAz, T0, impulse_response, modes[ctx->mode].pitch_sharp_factor);
 410
 411         convolute_with_sparse(fixed_vector, &fixed_cb, impulse_response,
 412                               SUBFR_SIZE);
 413
 414         avg_energy = (0.01 + avpriv_scalarproduct_float_c(fixed_vector,
 415                                                           fixed_vector,
 416                                                           SUBFR_SIZE)) /
 417                      SUBFR_SIZE;
 418
 419         ctx->past_pitch_gain = pitch_gain = gain_cb[params->gc_index[i]][0];
 420
 421         gain_code = ff_amr_set_fixed_gain(gain_cb[params->gc_index[i]][1],
 422                                           avg_energy, ctx->energy_history,
 423                                           34 - 15.0/(0.05*M_LN10/M_LN2),
 424                                           pred);
 425
 426         ff_weighted_vector_sumf(excitation, excitation, fixed_vector,
 427                                 pitch_gain, gain_code, SUBFR_SIZE);
 428
 429         pitch_gain *= 0.5 * pitch_gain;
 430         pitch_gain = FFMIN(pitch_gain, 0.4);
 431
 432         ctx->gain_mem = 0.7 * ctx->gain_mem + 0.3 * pitch_gain;
 433         ctx->gain_mem = FFMIN(ctx->gain_mem, pitch_gain);
 434         gain_code *= ctx->gain_mem;
 435
 436         for (j = 0; j < SUBFR_SIZE; j++)
 437             fixed_vector[j] = excitation[j] - gain_code * fixed_vector[j];
 438
 439         if (ctx->mode == MODE_5k0) {
 440             postfilter_5k0(ctx, pAz, fixed_vector);
 441
 442             ff_celp_lp_synthesis_filterf(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i*SUBFR_SIZE,
 443                                          pAz, excitation, SUBFR_SIZE,
 444                                          LP_FILTER_ORDER);
 445         }
 446
 447         ff_celp_lp_synthesis_filterf(synth + i*SUBFR_SIZE, pAz, fixed_vector,
 448                                      SUBFR_SIZE, LP_FILTER_ORDER);
 449
 450         excitation += SUBFR_SIZE;
 451     }
 452
 453     memcpy(synth - LP_FILTER_ORDER, synth + frame_size - LP_FILTER_ORDER,
 454            LP_FILTER_ORDER * sizeof(float));
 455
 456     if (ctx->mode == MODE_5k0) {
 457         for (i = 0; i < subframe_count; i++) {
 458             float energy = avpriv_scalarproduct_float_c(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,
 459                                                         ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,
 460                                                         SUBFR_SIZE);
 461             ff_adaptive_gain_control(&synth[i * SUBFR_SIZE],
 462                                      &synth[i * SUBFR_SIZE], energy,
 463                                      SUBFR_SIZE, 0.9, &ctx->postfilter_agc);
 464         }
 465
 466         memcpy(ctx->postfilter_syn5k0, ctx->postfilter_syn5k0 + frame_size,
 467                LP_FILTER_ORDER*sizeof(float));
 468     }
 469     memmove(ctx->excitation, excitation - PITCH_DELAY_MAX - L_INTERPOL,
 470            (PITCH_DELAY_MAX + L_INTERPOL) * sizeof(float));
 471
 472     ff_acelp_apply_order_2_transfer_function(out_data, synth,
 473                                              (const float[2]) {-1.99997   , 1.000000000},
 474                                              (const float[2]) {-1.93307352, 0.935891986},
 475                                              0.939805806,
 476                                              ctx->highpass_filt_mem,
 477                                              frame_size);
 478 }
 479
 480 static av_cold int sipr_decoder_init(AVCodecContext * avctx)
 481 {
 482     SiprContext *ctx = avctx->priv_data;
 483     int i;
 484
 485     switch (avctx->block_align) {
 486     case 20: ctx->mode = MODE_16k; break;
 487     case 19: ctx->mode = MODE_8k5; break;
 488     case 29: ctx->mode = MODE_6k5; break;
 489     case 37: ctx->mode = MODE_5k0; break;
 490     default:
 491         if      (avctx->bit_rate > 12200) ctx->mode = MODE_16k;
 492         else if (avctx->bit_rate > 7500 ) ctx->mode = MODE_8k5;
 493         else if (avctx->bit_rate > 5750 ) ctx->mode = MODE_6k5;
 494         else                              ctx->mode = MODE_5k0;
 495         av_log(avctx, AV_LOG_WARNING,
 496                "Invalid block_align: %d. Mode %s guessed based on bitrate: %d\n",
 497                avctx->block_align, modes[ctx->mode].mode_name, avctx->bit_rate);
 498     }
 499
 500     av_log(avctx, AV_LOG_DEBUG, "Mode: %s\n", modes[ctx->mode].mode_name);
 501
 502     if (ctx->mode == MODE_16k) {
 503         ff_sipr_init_16k(ctx);
 504         ctx->decode_frame = ff_sipr_decode_frame_16k;
 505     } else {
 506         ctx->decode_frame = decode_frame;
 507     }
 508
 509     for (i = 0; i < LP_FILTER_ORDER; i++)
 510         ctx->lsp_history[i] = cos((i+1) * M_PI / (LP_FILTER_ORDER + 1));
 511
 512     for (i = 0; i < 4; i++)
 513         ctx->energy_history[i] = -14;
 514
 515     avctx->channels       = 1;
 516     avctx->channel_layout = AV_CH_LAYOUT_MONO;
 517     avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;
 518
 519     return 0;
 520 }
 521
 522 static int sipr_decode_frame(AVCodecContext *avctx, void *data,
 523                              int *got_frame_ptr, AVPacket *avpkt)
 524 {
 525     SiprContext *ctx = avctx->priv_data;
 526     AVFrame *frame   = data;
 527     const uint8_t *buf=avpkt->data;
 528     SiprParameters parm;
 529     const SiprModeParam *mode_par = &modes[ctx->mode];
 530     GetBitContext gb;
 531     float *samples;
 532     int subframe_size = ctx->mode == MODE_16k ? L_SUBFR_16k : SUBFR_SIZE;
 533     int i, ret;
 534
 535     ctx->avctx = avctx;
 536     if (avpkt->size < (mode_par->bits_per_frame >> 3)) {
 537         av_log(avctx, AV_LOG_ERROR,
 538                "Error processing packet: packet size (%d) too small\n",
 539                avpkt->size);
 540         return -1;
 541     }
 542
 543     /* get output buffer */
 544     frame->nb_samples = mode_par->frames_per_packet * subframe_size *
 545                         mode_par->subframe_count;
 546     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
 547         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 548         return ret;
 549     }
 550     samples = (float *)frame->data[0];
 551
 552     init_get_bits(&gb, buf, mode_par->bits_per_frame);
 553
 554     for (i = 0; i < mode_par->frames_per_packet; i++) {
 555         decode_parameters(&parm, &gb, mode_par);
 556
 557         ctx->decode_frame(ctx, &parm, samples);
 558
 559         samples += subframe_size * mode_par->subframe_count;
 560     }
 561
 562     *got_frame_ptr = 1;
 563
 564     return mode_par->bits_per_frame >> 3;
 565 }
 566
 567 AVCodec ff_sipr_decoder = {
 568     .name           = "sipr",
 569     .type           = AVMEDIA_TYPE_AUDIO,
 570     .id             = AV_CODEC_ID_SIPR,
 571     .priv_data_size = sizeof(SiprContext),
 572     .init           = sipr_decoder_init,
 573     .decode         = sipr_decode_frame,
 574     .capabilities   = CODEC_CAP_DR1,
 575     .long_name      = NULL_IF_CONFIG_SMALL("RealAudio SIPR / ACELP.NET"),
 576 };