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 "config_components.h" 30 31#include <stdint.h> 32 33#include "libavutil/attributes.h" 34#include "libavutil/internal.h" 35#include "libavutil/mem_internal.h" 36 37#include "audiodsp.h" 38#include "ac3enc.h" 39#include "eac3enc.h" 40 41 42static int allocate_sample_buffers(AC3EncodeContext *s) 43{ 44 int ch; 45 46 if (!FF_ALLOC_TYPED_ARRAY(s->windowed_samples, AC3_WINDOW_SIZE) || 47 !FF_ALLOCZ_TYPED_ARRAY(s->planar_samples, s->channels)) 48 return AVERROR(ENOMEM); 49 50 for (ch = 0; ch < s->channels; ch++) { 51 if (!(s->planar_samples[ch] = av_mallocz((AC3_FRAME_SIZE + AC3_BLOCK_SIZE) * 52 sizeof(**s->planar_samples)))) 53 return AVERROR(ENOMEM); 54 } 55 return 0; 56} 57 58 59/* 60 * Copy input samples. 61 * Channels are reordered from FFmpeg's default order to AC-3 order. 62 */ 63static void copy_input_samples(AC3EncodeContext *s, SampleType **samples) 64{ 65 int ch; 66 67 /* copy and remap input samples */ 68 for (ch = 0; ch < s->channels; ch++) { 69 /* copy last 256 samples of previous frame to the start of the current frame */ 70 memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_BLOCK_SIZE * s->num_blocks], 71 AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0])); 72 73 /* copy new samples for current frame */ 74 memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE], 75 samples[s->channel_map[ch]], 76 AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0])); 77 } 78} 79 80 81/* 82 * Apply the MDCT to input samples to generate frequency coefficients. 83 * This applies the KBD window and normalizes the input to reduce precision 84 * loss due to fixed-point calculations. 85 */ 86static void apply_mdct(AC3EncodeContext *s) 87{ 88 int blk, ch; 89 90 for (ch = 0; ch < s->channels; ch++) { 91 for (blk = 0; blk < s->num_blocks; blk++) { 92 AC3Block *block = &s->blocks[blk]; 93 const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE]; 94 95 s->fdsp->vector_fmul(s->windowed_samples, input_samples, 96 s->mdct_window, AC3_BLOCK_SIZE); 97 s->fdsp->vector_fmul_reverse(s->windowed_samples + AC3_BLOCK_SIZE, 98 &input_samples[AC3_BLOCK_SIZE], 99 s->mdct_window, AC3_BLOCK_SIZE); 100 101 s->mdct.mdct_calc(&s->mdct, block->mdct_coef[ch+1], 102 s->windowed_samples); 103 } 104 } 105} 106 107 108/* 109 * Calculate coupling channel and coupling coordinates. 110 */ 111static void apply_channel_coupling(AC3EncodeContext *s) 112{ 113 LOCAL_ALIGNED_16(CoefType, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); 114#if AC3ENC_FLOAT 115 LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]); 116#else 117 int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords; 118#endif 119 int av_uninit(blk), ch, bnd, i, j; 120 CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}}; 121 int cpl_start, num_cpl_coefs; 122 123 memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); 124#if AC3ENC_FLOAT 125 memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords)); 126#endif 127 128 /* align start to 16-byte boundary. align length to multiple of 32. 129 note: coupling start bin % 4 will always be 1 */ 130 cpl_start = s->start_freq[CPL_CH] - 1; 131 num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32); 132 cpl_start = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs; 133 134 /* calculate coupling channel from fbw channels */ 135 for (blk = 0; blk < s->num_blocks; blk++) { 136 AC3Block *block = &s->blocks[blk]; 137 CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start]; 138 if (!block->cpl_in_use) 139 continue; 140 memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef)); 141 for (ch = 1; ch <= s->fbw_channels; ch++) { 142 CoefType *ch_coef = &block->mdct_coef[ch][cpl_start]; 143 if (!block->channel_in_cpl[ch]) 144 continue; 145 for (i = 0; i < num_cpl_coefs; i++) 146 cpl_coef[i] += ch_coef[i]; 147 } 148 149 /* coefficients must be clipped in order to be encoded */ 150 clip_coefficients(&s->adsp, cpl_coef, num_cpl_coefs); 151 } 152 153 /* calculate energy in each band in coupling channel and each fbw channel */ 154 /* TODO: possibly use SIMD to speed up energy calculation */ 155 bnd = 0; 156 i = s->start_freq[CPL_CH]; 157 while (i < s->cpl_end_freq) { 158 int band_size = s->cpl_band_sizes[bnd]; 159 for (ch = CPL_CH; ch <= s->fbw_channels; ch++) { 160 for (blk = 0; blk < s->num_blocks; blk++) { 161 AC3Block *block = &s->blocks[blk]; 162 if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch])) 163 continue; 164 for (j = 0; j < band_size; j++) { 165 CoefType v = block->mdct_coef[ch][i+j]; 166 MAC_COEF(energy[blk][ch][bnd], v, v); 167 } 168 } 169 } 170 i += band_size; 171 bnd++; 172 } 173 174 /* calculate coupling coordinates for all blocks for all channels */ 175 for (blk = 0; blk < s->num_blocks; blk++) { 176 AC3Block *block = &s->blocks[blk]; 177 if (!block->cpl_in_use) 178 continue; 179 for (ch = 1; ch <= s->fbw_channels; ch++) { 180 if (!block->channel_in_cpl[ch]) 181 continue; 182 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 183 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd], 184 energy[blk][CPL_CH][bnd]); 185 } 186 } 187 } 188 189 /* determine which blocks to send new coupling coordinates for */ 190 for (blk = 0; blk < s->num_blocks; blk++) { 191 AC3Block *block = &s->blocks[blk]; 192 AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL; 193 194 memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords)); 195 196 if (block->cpl_in_use) { 197 /* send new coordinates if this is the first block, if previous 198 * block did not use coupling but this block does, the channels 199 * using coupling has changed from the previous block, or the 200 * coordinate difference from the last block for any channel is 201 * greater than a threshold value. */ 202 if (blk == 0 || !block0->cpl_in_use) { 203 for (ch = 1; ch <= s->fbw_channels; ch++) 204 block->new_cpl_coords[ch] = 1; 205 } else { 206 for (ch = 1; ch <= s->fbw_channels; ch++) { 207 if (!block->channel_in_cpl[ch]) 208 continue; 209 if (!block0->channel_in_cpl[ch]) { 210 block->new_cpl_coords[ch] = 1; 211 } else { 212 CoefSumType coord_diff = 0; 213 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 214 coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] - 215 cpl_coords[blk ][ch][bnd]); 216 } 217 coord_diff /= s->num_cpl_bands; 218 if (coord_diff > NEW_CPL_COORD_THRESHOLD) 219 block->new_cpl_coords[ch] = 1; 220 } 221 } 222 } 223 } 224 } 225 226 /* calculate final coupling coordinates, taking into account reusing of 227 coordinates in successive blocks */ 228 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 229 blk = 0; 230 while (blk < s->num_blocks) { 231 int av_uninit(blk1); 232 AC3Block *block = &s->blocks[blk]; 233 234 if (!block->cpl_in_use) { 235 blk++; 236 continue; 237 } 238 239 for (ch = 1; ch <= s->fbw_channels; ch++) { 240 CoefSumType energy_ch, energy_cpl; 241 if (!block->channel_in_cpl[ch]) 242 continue; 243 energy_cpl = energy[blk][CPL_CH][bnd]; 244 energy_ch = energy[blk][ch][bnd]; 245 blk1 = blk+1; 246 while (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) { 247 if (s->blocks[blk1].cpl_in_use) { 248 energy_cpl += energy[blk1][CPL_CH][bnd]; 249 energy_ch += energy[blk1][ch][bnd]; 250 } 251 blk1++; 252 } 253 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl); 254 } 255 blk = blk1; 256 } 257 } 258 259 /* calculate exponents/mantissas for coupling coordinates */ 260 for (blk = 0; blk < s->num_blocks; blk++) { 261 AC3Block *block = &s->blocks[blk]; 262 if (!block->cpl_in_use) 263 continue; 264 265#if AC3ENC_FLOAT 266 s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1], 267 cpl_coords[blk][1], 268 s->fbw_channels * 16); 269#endif 270 s->ac3dsp.extract_exponents(block->cpl_coord_exp[1], 271 fixed_cpl_coords[blk][1], 272 s->fbw_channels * 16); 273 274 for (ch = 1; ch <= s->fbw_channels; ch++) { 275 int bnd, min_exp, max_exp, master_exp; 276 277 if (!block->new_cpl_coords[ch]) 278 continue; 279 280 /* determine master exponent */ 281 min_exp = max_exp = block->cpl_coord_exp[ch][0]; 282 for (bnd = 1; bnd < s->num_cpl_bands; bnd++) { 283 int exp = block->cpl_coord_exp[ch][bnd]; 284 min_exp = FFMIN(exp, min_exp); 285 max_exp = FFMAX(exp, max_exp); 286 } 287 master_exp = ((max_exp - 15) + 2) / 3; 288 master_exp = FFMAX(master_exp, 0); 289 while (min_exp < master_exp * 3) 290 master_exp--; 291 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 292 block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] - 293 master_exp * 3, 0, 15); 294 } 295 block->cpl_master_exp[ch] = master_exp; 296 297 /* quantize mantissas */ 298 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { 299 int cpl_exp = block->cpl_coord_exp[ch][bnd]; 300 int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24; 301 if (cpl_exp == 15) 302 cpl_mant >>= 1; 303 else 304 cpl_mant -= 16; 305 306 block->cpl_coord_mant[ch][bnd] = cpl_mant; 307 } 308 } 309 } 310 311 if (AC3ENC_FLOAT && CONFIG_EAC3_ENCODER && s->eac3) 312 ff_eac3_set_cpl_states(s); 313} 314 315 316/* 317 * Determine rematrixing flags for each block and band. 318 */ 319static void compute_rematrixing_strategy(AC3EncodeContext *s) 320{ 321 int nb_coefs; 322 int blk, bnd; 323 AC3Block *block, *block0 = NULL; 324 325 if (s->channel_mode != AC3_CHMODE_STEREO) 326 return; 327 328 for (blk = 0; blk < s->num_blocks; blk++) { 329 block = &s->blocks[blk]; 330 block->new_rematrixing_strategy = !blk; 331 332 block->num_rematrixing_bands = 4; 333 if (block->cpl_in_use) { 334 block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61); 335 block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37); 336 if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands) 337 block->new_rematrixing_strategy = 1; 338 } 339 nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]); 340 341 if (!s->rematrixing_enabled) { 342 block0 = block; 343 continue; 344 } 345 346 for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) { 347 /* calculate sum of squared coeffs for one band in one block */ 348 int start = ff_ac3_rematrix_band_tab[bnd]; 349 int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]); 350 CoefSumType sum[4]; 351 sum_square_butterfly(s, sum, block->mdct_coef[1] + start, 352 block->mdct_coef[2] + start, end - start); 353 354 /* compare sums to determine if rematrixing will be used for this band */ 355 if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1])) 356 block->rematrixing_flags[bnd] = 1; 357 else 358 block->rematrixing_flags[bnd] = 0; 359 360 /* determine if new rematrixing flags will be sent */ 361 if (blk && 362 block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) { 363 block->new_rematrixing_strategy = 1; 364 } 365 } 366 block0 = block; 367 } 368} 369 370 371int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt, 372 const AVFrame *frame, int *got_packet_ptr) 373{ 374 AC3EncodeContext *s = avctx->priv_data; 375 int ret; 376 377 if (s->options.allow_per_frame_metadata) { 378 ret = ff_ac3_validate_metadata(s); 379 if (ret) 380 return ret; 381 } 382 383 if (s->bit_alloc.sr_code == 1 || (AC3ENC_FLOAT && s->eac3)) 384 ff_ac3_adjust_frame_size(s); 385 386 copy_input_samples(s, (SampleType **)frame->extended_data); 387 388 apply_mdct(s); 389 390 s->cpl_on = s->cpl_enabled; 391 ff_ac3_compute_coupling_strategy(s); 392 393 if (s->cpl_on) 394 apply_channel_coupling(s); 395 396 compute_rematrixing_strategy(s); 397 398#if AC3ENC_FLOAT 399 scale_coefficients(s); 400#endif 401 402 return ff_ac3_encode_frame_common_end(avctx, avpkt, frame, got_packet_ptr); 403} 404