1/* 2 * AC-3 encoder float/fixed template 3 * Copyright (c) 2000 Fabrice Bellard 4 * Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com> 5 * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> 6 * 7 * This file is part of FFmpeg. 8 * 9 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 22 */ 23 24/** 25 * @file 26 * AC-3 encoder float/fixed template 27 */ 28 29#include <stdint.h> 30 31#include "libavutil/attributes.h" 32#include "libavutil/internal.h" 33 34#include "audiodsp.h" 35#include "internal.h" 36#include "ac3enc.h" 37#include "eac3enc.h" 38 39/* prototypes for static functions in ac3enc_fixed.c and ac3enc_float.c */ 40 41static void scale_coefficients(AC3EncodeContext *s); 42 43static int normalize_samples(AC3EncodeContext *s); 44 45static void clip_coefficients(AudioDSPContext *adsp, CoefType *coef, 46 unsigned int len); 47 48static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl); 49 50static void sum_square_butterfly(AC3EncodeContext *s, CoefSumType sum[4], 51 const CoefType *coef0, const CoefType *coef1, 52 int len); 53 54int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s) 55{ 56 int ch; 57 58 FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE * 59 sizeof(*s->windowed_samples), alloc_fail); 60 FF_ALLOC_OR_GOTO(s->avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples), 61 alloc_fail); 62 for (ch = 0; ch < s->channels; ch++) { 63 FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch], 64 (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples), 65 alloc_fail); 66 } 67 68 return 0; 69alloc_fail: 70 return AVERROR(ENOMEM); 71} 72 73 74/* 75 * Copy input samples. 76 * Channels are reordered from FFmpeg's default order to AC-3 order. 77 */ 78static void copy_input_samples(AC3EncodeContext *s, SampleType **samples) 79{ 80 int ch; 81 82 /* copy and remap input samples */ 83 for (ch = 0; ch < s->channels; ch++) { 84 /* copy last 256 samples of previous frame to the start of the current frame */ 85 memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_BLOCK_SIZE * s->num_blocks], 86 AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); 87 88 /* copy new samples for current frame */ 89 memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE], 90 samples[s->channel_map[ch]], 91 AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0])); 92 } 93} 94 95 96/* 97 * Apply the MDCT to input samples to generate frequency coefficients. 98 * This applies the KBD window and normalizes the input to reduce precision 99 * loss due to fixed-point calculations. 100 */ 101static void apply_mdct(AC3EncodeContext *s) 102{ 103 int blk, ch; 104 105 for (ch = 0; ch < s->channels; ch++) { 106 for (blk = 0; blk < s->num_blocks; blk++) { 107 AC3Block *block = &s->blocks[blk]; 108 const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE]; 109 110#if CONFIG_AC3ENC_FLOAT 111 s->fdsp.vector_fmul(s->windowed_samples, input_samples, 112 s->mdct_window, AC3_WINDOW_SIZE); 113#else 114 s->ac3dsp.apply_window_int16(s->windowed_samples, input_samples, 115 s->mdct_window, AC3_WINDOW_SIZE); 116#endif 117 118 if (s->fixed_point) 119 block->coeff_shift[ch+1] = normalize_samples(s); 120 121 s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1], 122 s->windowed_samples); 123 } 124 } 125} 126 127 128/* 129 * Calculate coupling channel and coupling coordinates. 130 */ 131static void apply_channel_coupling(AC3EncodeContext *s) 132{ 133 LOCAL_ALIGNED_16(CoefType, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); 134#if CONFIG_AC3ENC_FLOAT 135 LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); 136#else 137 int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords; 138#endif 139 int av_uninit(blk), ch, bnd, i, j; 140 CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}}; 141 int cpl_start, num_cpl_coefs; 142 143 memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); 144#if CONFIG_AC3ENC_FLOAT 145 memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); 146#endif 147 148 /* align start to 16-byte boundary. align length to multiple of 32. 149 note: coupling start bin % 4 will always be 1 */ 150 cpl_start = s->start_freq[CPL_CH] - 1; 151 num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32); 152 cpl_start = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs; 153 154 /* calculate coupling channel from fbw channels */ 155 for (blk = 0; blk < s->num_blocks; blk++) { 156 AC3Block *block = &s->blocks[blk]; 157 CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start]; 158 if (!block->cpl_in_use) 159 continue; 160 memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef)); 161 for (ch = 1; ch <= s->fbw_channels; ch++) { 162 CoefType *ch_coef = &block->mdct_coef[ch][cpl_start]; 163 if (!block->channel_in_cpl[ch]) 164 continue; 165 for (i = 0; i < num_cpl_coefs; i++) 166 cpl_coef[i] += ch_coef[i]; 167 } 168 169 /* coefficients must be clipped in order to be encoded */ 170 clip_coefficients(&s->adsp, cpl_coef, num_cpl_coefs); 171 } 172 173 /* calculate energy in each band in coupling channel and each fbw channel */ 174 /* TODO: possibly use SIMD to speed up energy calculation */ 175 bnd = 0; 176 i = s->start_freq[CPL_CH]; 177 while (i < s->cpl_end_freq) { 178 int band_size = s->cpl_band_sizes[bnd]; 179 for (ch = CPL_CH; ch <= s->fbw_channels; ch++) { 180 for (blk = 0; blk < s->num_blocks; blk++) { 181 AC3Block *block = &s->blocks[blk]; 182 if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch])) 183 continue; 184 for (j = 0; j < band_size; j++) { 185 CoefType v = block->mdct_coef[ch][i+j]; 186 MAC_COEF(energy[blk][ch][bnd], v, v); 187 } 188 } 189 } 190 i += band_size; 191 bnd++; 192 } 193 194 /* calculate coupling coordinates for all blocks for all channels */ 195 for (blk = 0; blk < s->num_blocks; blk++) { 196 AC3Block *block = &s->blocks[blk]; 197 if (!block->cpl_in_use) 198 continue; 199 for (ch = 1; ch <= s->fbw_channels; ch++) { 200 if (!block->channel_in_cpl[ch]) 201 continue; 202 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 203 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd], 204 energy[blk][CPL_CH][bnd]); 205 } 206 } 207 } 208 209 /* determine which blocks to send new coupling coordinates for */ 210 for (blk = 0; blk < s->num_blocks; blk++) { 211 AC3Block *block = &s->blocks[blk]; 212 AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL; 213 214 memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords)); 215 216 if (block->cpl_in_use) { 217 /* send new coordinates if this is the first block, if previous 218 * block did not use coupling but this block does, the channels 219 * using coupling has changed from the previous block, or the 220 * coordinate difference from the last block for any channel is 221 * greater than a threshold value. */ 222 if (blk == 0 || !block0->cpl_in_use) { 223 for (ch = 1; ch <= s->fbw_channels; ch++) 224 block->new_cpl_coords[ch] = 1; 225 } else { 226 for (ch = 1; ch <= s->fbw_channels; ch++) { 227 if (!block->channel_in_cpl[ch]) 228 continue; 229 if (!block0->channel_in_cpl[ch]) { 230 block->new_cpl_coords[ch] = 1; 231 } else { 232 CoefSumType coord_diff = 0; 233 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 234 coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] - 235 cpl_coords[blk ][ch][bnd]); 236 } 237 coord_diff /= s->num_cpl_bands; 238 if (coord_diff > NEW_CPL_COORD_THRESHOLD) 239 block->new_cpl_coords[ch] = 1; 240 } 241 } 242 } 243 } 244 } 245 246 /* calculate final coupling coordinates, taking into account reusing of 247 coordinates in successive blocks */ 248 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 249 blk = 0; 250 while (blk < s->num_blocks) { 251 int av_uninit(blk1); 252 AC3Block *block = &s->blocks[blk]; 253 254 if (!block->cpl_in_use) { 255 blk++; 256 continue; 257 } 258 259 for (ch = 1; ch <= s->fbw_channels; ch++) { 260 CoefSumType energy_ch, energy_cpl; 261 if (!block->channel_in_cpl[ch]) 262 continue; 263 energy_cpl = energy[blk][CPL_CH][bnd]; 264 energy_ch = energy[blk][ch][bnd]; 265 blk1 = blk+1; 266 while (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) { 267 if (s->blocks[blk1].cpl_in_use) { 268 energy_cpl += energy[blk1][CPL_CH][bnd]; 269 energy_ch += energy[blk1][ch][bnd]; 270 } 271 blk1++; 272 } 273 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl); 274 } 275 blk = blk1; 276 } 277 } 278 279 /* calculate exponents/mantissas for coupling coordinates */ 280 for (blk = 0; blk < s->num_blocks; blk++) { 281 AC3Block *block = &s->blocks[blk]; 282 if (!block->cpl_in_use) 283 continue; 284 285#if CONFIG_AC3ENC_FLOAT 286 s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1], 287 cpl_coords[blk][1], 288 s->fbw_channels * 16); 289#endif 290 s->ac3dsp.extract_exponents(block->cpl_coord_exp[1], 291 fixed_cpl_coords[blk][1], 292 s->fbw_channels * 16); 293 294 for (ch = 1; ch <= s->fbw_channels; ch++) { 295 int bnd, min_exp, max_exp, master_exp; 296 297 if (!block->new_cpl_coords[ch]) 298 continue; 299 300 /* determine master exponent */ 301 min_exp = max_exp = block->cpl_coord_exp[ch][0]; 302 for (bnd = 1; bnd < s->num_cpl_bands; bnd++) { 303 int exp = block->cpl_coord_exp[ch][bnd]; 304 min_exp = FFMIN(exp, min_exp); 305 max_exp = FFMAX(exp, max_exp); 306 } 307 master_exp = ((max_exp - 15) + 2) / 3; 308 master_exp = FFMAX(master_exp, 0); 309 while (min_exp < master_exp * 3) 310 master_exp--; 311 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 312 block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] - 313 master_exp * 3, 0, 15); 314 } 315 block->cpl_master_exp[ch] = master_exp; 316 317 /* quantize mantissas */ 318 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 319 int cpl_exp = block->cpl_coord_exp[ch][bnd]; 320 int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24; 321 if (cpl_exp == 15) 322 cpl_mant >>= 1; 323 else 324 cpl_mant -= 16; 325 326 block->cpl_coord_mant[ch][bnd] = cpl_mant; 327 } 328 } 329 } 330 331 if (CONFIG_EAC3_ENCODER && s->eac3) 332 ff_eac3_set_cpl_states(s); 333} 334 335 336/* 337 * Determine rematrixing flags for each block and band. 338 */ 339static void compute_rematrixing_strategy(AC3EncodeContext *s) 340{ 341 int nb_coefs; 342 int blk, bnd; 343 AC3Block *block, *block0 = NULL; 344 345 if (s->channel_mode != AC3_CHMODE_STEREO) 346 return; 347 348 for (blk = 0; blk < s->num_blocks; blk++) { 349 block = &s->blocks[blk]; 350 block->new_rematrixing_strategy = !blk; 351 352 block->num_rematrixing_bands = 4; 353 if (block->cpl_in_use) { 354 block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61); 355 block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37); 356 if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands) 357 block->new_rematrixing_strategy = 1; 358 } 359 nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]); 360 361 if (!s->rematrixing_enabled) { 362 block0 = block; 363 continue; 364 } 365 366 for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { 367 /* calculate sum of squared coeffs for one band in one block */ 368 int start = ff_ac3_rematrix_band_tab[bnd]; 369 int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]); 370 CoefSumType sum[4]; 371 sum_square_butterfly(s, sum, block->mdct_coef[1] + start, 372 block->mdct_coef[2] + start, end - start); 373 374 /* compare sums to determine if rematrixing will be used for this band */ 375 if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1])) 376 block->rematrixing_flags[bnd] = 1; 377 else 378 block->rematrixing_flags[bnd] = 0; 379 380 /* determine if new rematrixing flags will be sent */ 381 if (blk && 382 block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) { 383 block->new_rematrixing_strategy = 1; 384 } 385 } 386 block0 = block; 387 } 388} 389 390 391int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt, 392 const AVFrame *frame, int *got_packet_ptr) 393{ 394 AC3EncodeContext *s = avctx->priv_data; 395 int ret; 396 397 if (s->options.allow_per_frame_metadata) { 398 ret = ff_ac3_validate_metadata(s); 399 if (ret) 400 return ret; 401 } 402 403 if (s->bit_alloc.sr_code == 1 || s->eac3) 404 ff_ac3_adjust_frame_size(s); 405 406 copy_input_samples(s, (SampleType **)frame->extended_data); 407 408 apply_mdct(s); 409 410 if (s->fixed_point) 411 scale_coefficients(s); 412 413 clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1], 414 AC3_MAX_COEFS * s->num_blocks * s->channels); 415 416 s->cpl_on = s->cpl_enabled; 417 ff_ac3_compute_coupling_strategy(s); 418 419 if (s->cpl_on) 420 apply_channel_coupling(s); 421 422 compute_rematrixing_strategy(s); 423 424 if (!s->fixed_point) 425 scale_coefficients(s); 426 427 ff_ac3_apply_rematrixing(s); 428 429 ff_ac3_process_exponents(s); 430 431 ret = ff_ac3_compute_bit_allocation(s); 432 if (ret) { 433 av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n"); 434 return ret; 435 } 436 437 ff_ac3_group_exponents(s); 438 439 ff_ac3_quantize_mantissas(s); 440 441 if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size)) < 0) 442 return ret; 443 ff_ac3_output_frame(s, avpkt->data); 444 445 if (frame->pts != AV_NOPTS_VALUE) 446 avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->delay); 447 448 *got_packet_ptr = 1; 449 return 0; 450} 451