| 1 | /* |
| 2 | * AAC encoder psychoacoustic model |
| 3 | * Copyright (C) 2008 Konstantin Shishkov |
| 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 | * AAC encoder psychoacoustic model |
| 25 | */ |
| 26 | |
| 27 | #include "libavutil/attributes.h" |
| 28 | #include "libavutil/libm.h" |
| 29 | |
| 30 | #include "avcodec.h" |
| 31 | #include "aactab.h" |
| 32 | #include "psymodel.h" |
| 33 | |
| 34 | /*********************************** |
| 35 | * TODOs: |
| 36 | * try other bitrate controlling mechanism (maybe use ratecontrol.c?) |
| 37 | * control quality for quality-based output |
| 38 | **********************************/ |
| 39 | |
| 40 | /** |
| 41 | * constants for 3GPP AAC psychoacoustic model |
| 42 | * @{ |
| 43 | */ |
| 44 | #define PSY_3GPP_THR_SPREAD_HI 1.5f // spreading factor for low-to-hi threshold spreading (15 dB/Bark) |
| 45 | #define PSY_3GPP_THR_SPREAD_LOW 3.0f // spreading factor for hi-to-low threshold spreading (30 dB/Bark) |
| 46 | /* spreading factor for low-to-hi energy spreading, long block, > 22kbps/channel (20dB/Bark) */ |
| 47 | #define PSY_3GPP_EN_SPREAD_HI_L1 2.0f |
| 48 | /* spreading factor for low-to-hi energy spreading, long block, <= 22kbps/channel (15dB/Bark) */ |
| 49 | #define PSY_3GPP_EN_SPREAD_HI_L2 1.5f |
| 50 | /* spreading factor for low-to-hi energy spreading, short block (15 dB/Bark) */ |
| 51 | #define PSY_3GPP_EN_SPREAD_HI_S 1.5f |
| 52 | /* spreading factor for hi-to-low energy spreading, long block (30dB/Bark) */ |
| 53 | #define PSY_3GPP_EN_SPREAD_LOW_L 3.0f |
| 54 | /* spreading factor for hi-to-low energy spreading, short block (20dB/Bark) */ |
| 55 | #define PSY_3GPP_EN_SPREAD_LOW_S 2.0f |
| 56 | |
| 57 | #define PSY_3GPP_RPEMIN 0.01f |
| 58 | #define PSY_3GPP_RPELEV 2.0f |
| 59 | |
| 60 | #define PSY_3GPP_C1 3.0f /* log2(8) */ |
| 61 | #define PSY_3GPP_C2 1.3219281f /* log2(2.5) */ |
| 62 | #define PSY_3GPP_C3 0.55935729f /* 1 - C2 / C1 */ |
| 63 | |
| 64 | #define PSY_SNR_1DB 7.9432821e-1f /* -1dB */ |
| 65 | #define PSY_SNR_25DB 3.1622776e-3f /* -25dB */ |
| 66 | |
| 67 | #define PSY_3GPP_SAVE_SLOPE_L -0.46666667f |
| 68 | #define PSY_3GPP_SAVE_SLOPE_S -0.36363637f |
| 69 | #define PSY_3GPP_SAVE_ADD_L -0.84285712f |
| 70 | #define PSY_3GPP_SAVE_ADD_S -0.75f |
| 71 | #define PSY_3GPP_SPEND_SLOPE_L 0.66666669f |
| 72 | #define PSY_3GPP_SPEND_SLOPE_S 0.81818181f |
| 73 | #define PSY_3GPP_SPEND_ADD_L -0.35f |
| 74 | #define PSY_3GPP_SPEND_ADD_S -0.26111111f |
| 75 | #define PSY_3GPP_CLIP_LO_L 0.2f |
| 76 | #define PSY_3GPP_CLIP_LO_S 0.2f |
| 77 | #define PSY_3GPP_CLIP_HI_L 0.95f |
| 78 | #define PSY_3GPP_CLIP_HI_S 0.75f |
| 79 | |
| 80 | #define PSY_3GPP_AH_THR_LONG 0.5f |
| 81 | #define PSY_3GPP_AH_THR_SHORT 0.63f |
| 82 | |
| 83 | enum { |
| 84 | PSY_3GPP_AH_NONE, |
| 85 | PSY_3GPP_AH_INACTIVE, |
| 86 | PSY_3GPP_AH_ACTIVE |
| 87 | }; |
| 88 | |
| 89 | #define PSY_3GPP_BITS_TO_PE(bits) ((bits) * 1.18f) |
| 90 | |
| 91 | /* LAME psy model constants */ |
| 92 | #define PSY_LAME_FIR_LEN 21 ///< LAME psy model FIR order |
| 93 | #define AAC_BLOCK_SIZE_LONG 1024 ///< long block size |
| 94 | #define AAC_BLOCK_SIZE_SHORT 128 ///< short block size |
| 95 | #define AAC_NUM_BLOCKS_SHORT 8 ///< number of blocks in a short sequence |
| 96 | #define PSY_LAME_NUM_SUBBLOCKS 3 ///< Number of sub-blocks in each short block |
| 97 | |
| 98 | /** |
| 99 | * @} |
| 100 | */ |
| 101 | |
| 102 | /** |
| 103 | * information for single band used by 3GPP TS26.403-inspired psychoacoustic model |
| 104 | */ |
| 105 | typedef struct AacPsyBand{ |
| 106 | float energy; ///< band energy |
| 107 | float thr; ///< energy threshold |
| 108 | float thr_quiet; ///< threshold in quiet |
| 109 | float nz_lines; ///< number of non-zero spectral lines |
| 110 | float active_lines; ///< number of active spectral lines |
| 111 | float pe; ///< perceptual entropy |
| 112 | float pe_const; ///< constant part of the PE calculation |
| 113 | float norm_fac; ///< normalization factor for linearization |
| 114 | int avoid_holes; ///< hole avoidance flag |
| 115 | }AacPsyBand; |
| 116 | |
| 117 | /** |
| 118 | * single/pair channel context for psychoacoustic model |
| 119 | */ |
| 120 | typedef struct AacPsyChannel{ |
| 121 | AacPsyBand band[128]; ///< bands information |
| 122 | AacPsyBand prev_band[128]; ///< bands information from the previous frame |
| 123 | |
| 124 | float win_energy; ///< sliding average of channel energy |
| 125 | float iir_state[2]; ///< hi-pass IIR filter state |
| 126 | uint8_t next_grouping; ///< stored grouping scheme for the next frame (in case of 8 short window sequence) |
| 127 | enum WindowSequence next_window_seq; ///< window sequence to be used in the next frame |
| 128 | /* LAME psy model specific members */ |
| 129 | float attack_threshold; ///< attack threshold for this channel |
| 130 | float prev_energy_subshort[AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS]; |
| 131 | int prev_attack; ///< attack value for the last short block in the previous sequence |
| 132 | }AacPsyChannel; |
| 133 | |
| 134 | /** |
| 135 | * psychoacoustic model frame type-dependent coefficients |
| 136 | */ |
| 137 | typedef struct AacPsyCoeffs{ |
| 138 | float ath; ///< absolute threshold of hearing per bands |
| 139 | float barks; ///< Bark value for each spectral band in long frame |
| 140 | float spread_low[2]; ///< spreading factor for low-to-high threshold spreading in long frame |
| 141 | float spread_hi [2]; ///< spreading factor for high-to-low threshold spreading in long frame |
| 142 | float min_snr; ///< minimal SNR |
| 143 | }AacPsyCoeffs; |
| 144 | |
| 145 | /** |
| 146 | * 3GPP TS26.403-inspired psychoacoustic model specific data |
| 147 | */ |
| 148 | typedef struct AacPsyContext{ |
| 149 | int chan_bitrate; ///< bitrate per channel |
| 150 | int frame_bits; ///< average bits per frame |
| 151 | int fill_level; ///< bit reservoir fill level |
| 152 | struct { |
| 153 | float min; ///< minimum allowed PE for bit factor calculation |
| 154 | float max; ///< maximum allowed PE for bit factor calculation |
| 155 | float previous; ///< allowed PE of the previous frame |
| 156 | float correction; ///< PE correction factor |
| 157 | } pe; |
| 158 | AacPsyCoeffs psy_coef[2][64]; |
| 159 | AacPsyChannel *ch; |
| 160 | }AacPsyContext; |
| 161 | |
| 162 | /** |
| 163 | * LAME psy model preset struct |
| 164 | */ |
| 165 | typedef struct { |
| 166 | int quality; ///< Quality to map the rest of the vaules to. |
| 167 | /* This is overloaded to be both kbps per channel in ABR mode, and |
| 168 | * requested quality in constant quality mode. |
| 169 | */ |
| 170 | float st_lrm; ///< short threshold for L, R, and M channels |
| 171 | } PsyLamePreset; |
| 172 | |
| 173 | /** |
| 174 | * LAME psy model preset table for ABR |
| 175 | */ |
| 176 | static const PsyLamePreset psy_abr_map[] = { |
| 177 | /* TODO: Tuning. These were taken from LAME. */ |
| 178 | /* kbps/ch st_lrm */ |
| 179 | { 8, 6.60}, |
| 180 | { 16, 6.60}, |
| 181 | { 24, 6.60}, |
| 182 | { 32, 6.60}, |
| 183 | { 40, 6.60}, |
| 184 | { 48, 6.60}, |
| 185 | { 56, 6.60}, |
| 186 | { 64, 6.40}, |
| 187 | { 80, 6.00}, |
| 188 | { 96, 5.60}, |
| 189 | {112, 5.20}, |
| 190 | {128, 5.20}, |
| 191 | {160, 5.20} |
| 192 | }; |
| 193 | |
| 194 | /** |
| 195 | * LAME psy model preset table for constant quality |
| 196 | */ |
| 197 | static const PsyLamePreset psy_vbr_map[] = { |
| 198 | /* vbr_q st_lrm */ |
| 199 | { 0, 4.20}, |
| 200 | { 1, 4.20}, |
| 201 | { 2, 4.20}, |
| 202 | { 3, 4.20}, |
| 203 | { 4, 4.20}, |
| 204 | { 5, 4.20}, |
| 205 | { 6, 4.20}, |
| 206 | { 7, 4.20}, |
| 207 | { 8, 4.20}, |
| 208 | { 9, 4.20}, |
| 209 | {10, 4.20} |
| 210 | }; |
| 211 | |
| 212 | /** |
| 213 | * LAME psy model FIR coefficient table |
| 214 | */ |
| 215 | static const float psy_fir_coeffs[] = { |
| 216 | -8.65163e-18 * 2, -0.00851586 * 2, -6.74764e-18 * 2, 0.0209036 * 2, |
| 217 | -3.36639e-17 * 2, -0.0438162 * 2, -1.54175e-17 * 2, 0.0931738 * 2, |
| 218 | -5.52212e-17 * 2, -0.313819 * 2 |
| 219 | }; |
| 220 | |
| 221 | #if ARCH_MIPS |
| 222 | # include "mips/aacpsy_mips.h" |
| 223 | #endif /* ARCH_MIPS */ |
| 224 | |
| 225 | /** |
| 226 | * Calculate the ABR attack threshold from the above LAME psymodel table. |
| 227 | */ |
| 228 | static float lame_calc_attack_threshold(int bitrate) |
| 229 | { |
| 230 | /* Assume max bitrate to start with */ |
| 231 | int lower_range = 12, upper_range = 12; |
| 232 | int lower_range_kbps = psy_abr_map[12].quality; |
| 233 | int upper_range_kbps = psy_abr_map[12].quality; |
| 234 | int i; |
| 235 | |
| 236 | /* Determine which bitrates the value specified falls between. |
| 237 | * If the loop ends without breaking our above assumption of 320kbps was correct. |
| 238 | */ |
| 239 | for (i = 1; i < 13; i++) { |
| 240 | if (FFMAX(bitrate, psy_abr_map[i].quality) != bitrate) { |
| 241 | upper_range = i; |
| 242 | upper_range_kbps = psy_abr_map[i ].quality; |
| 243 | lower_range = i - 1; |
| 244 | lower_range_kbps = psy_abr_map[i - 1].quality; |
| 245 | break; /* Upper range found */ |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /* Determine which range the value specified is closer to */ |
| 250 | if ((upper_range_kbps - bitrate) > (bitrate - lower_range_kbps)) |
| 251 | return psy_abr_map[lower_range].st_lrm; |
| 252 | return psy_abr_map[upper_range].st_lrm; |
| 253 | } |
| 254 | |
| 255 | /** |
| 256 | * LAME psy model specific initialization |
| 257 | */ |
| 258 | static av_cold void lame_window_init(AacPsyContext *ctx, AVCodecContext *avctx) |
| 259 | { |
| 260 | int i, j; |
| 261 | |
| 262 | for (i = 0; i < avctx->channels; i++) { |
| 263 | AacPsyChannel *pch = &ctx->ch[i]; |
| 264 | |
| 265 | if (avctx->flags & CODEC_FLAG_QSCALE) |
| 266 | pch->attack_threshold = psy_vbr_map[avctx->global_quality / FF_QP2LAMBDA].st_lrm; |
| 267 | else |
| 268 | pch->attack_threshold = lame_calc_attack_threshold(avctx->bit_rate / avctx->channels / 1000); |
| 269 | |
| 270 | for (j = 0; j < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; j++) |
| 271 | pch->prev_energy_subshort[j] = 10.0f; |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | /** |
| 276 | * Calculate Bark value for given line. |
| 277 | */ |
| 278 | static av_cold float calc_bark(float f) |
| 279 | { |
| 280 | return 13.3f * atanf(0.00076f * f) + 3.5f * atanf((f / 7500.0f) * (f / 7500.0f)); |
| 281 | } |
| 282 | |
| 283 | #define ATH_ADD 4 |
| 284 | /** |
| 285 | * Calculate ATH value for given frequency. |
| 286 | * Borrowed from Lame. |
| 287 | */ |
| 288 | static av_cold float ath(float f, float add) |
| 289 | { |
| 290 | f /= 1000.0f; |
| 291 | return 3.64 * pow(f, -0.8) |
| 292 | - 6.8 * exp(-0.6 * (f - 3.4) * (f - 3.4)) |
| 293 | + 6.0 * exp(-0.15 * (f - 8.7) * (f - 8.7)) |
| 294 | + (0.6 + 0.04 * add) * 0.001 * f * f * f * f; |
| 295 | } |
| 296 | |
| 297 | static av_cold int psy_3gpp_init(FFPsyContext *ctx) { |
| 298 | AacPsyContext *pctx; |
| 299 | float bark; |
| 300 | int i, j, g, start; |
| 301 | float prev, minscale, minath, minsnr, pe_min; |
| 302 | const int chan_bitrate = ctx->avctx->bit_rate / ctx->avctx->channels; |
| 303 | const int bandwidth = ctx->avctx->cutoff ? ctx->avctx->cutoff : AAC_CUTOFF(ctx->avctx); |
| 304 | const float num_bark = calc_bark((float)bandwidth); |
| 305 | |
| 306 | ctx->model_priv_data = av_mallocz(sizeof(AacPsyContext)); |
| 307 | pctx = (AacPsyContext*) ctx->model_priv_data; |
| 308 | |
| 309 | pctx->chan_bitrate = chan_bitrate; |
| 310 | pctx->frame_bits = chan_bitrate * AAC_BLOCK_SIZE_LONG / ctx->avctx->sample_rate; |
| 311 | pctx->pe.min = 8.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f); |
| 312 | pctx->pe.max = 12.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f); |
| 313 | ctx->bitres.size = 6144 - pctx->frame_bits; |
| 314 | ctx->bitres.size -= ctx->bitres.size % 8; |
| 315 | pctx->fill_level = ctx->bitres.size; |
| 316 | minath = ath(3410, ATH_ADD); |
| 317 | for (j = 0; j < 2; j++) { |
| 318 | AacPsyCoeffs *coeffs = pctx->psy_coef[j]; |
| 319 | const uint8_t *band_sizes = ctx->bands[j]; |
| 320 | float line_to_frequency = ctx->avctx->sample_rate / (j ? 256.f : 2048.0f); |
| 321 | float avg_chan_bits = chan_bitrate * (j ? 128.0f : 1024.0f) / ctx->avctx->sample_rate; |
| 322 | /* reference encoder uses 2.4% here instead of 60% like the spec says */ |
| 323 | float bark_pe = 0.024f * PSY_3GPP_BITS_TO_PE(avg_chan_bits) / num_bark; |
| 324 | float en_spread_low = j ? PSY_3GPP_EN_SPREAD_LOW_S : PSY_3GPP_EN_SPREAD_LOW_L; |
| 325 | /* High energy spreading for long blocks <= 22kbps/channel and short blocks are the same. */ |
| 326 | float en_spread_hi = (j || (chan_bitrate <= 22.0f)) ? PSY_3GPP_EN_SPREAD_HI_S : PSY_3GPP_EN_SPREAD_HI_L1; |
| 327 | |
| 328 | i = 0; |
| 329 | prev = 0.0; |
| 330 | for (g = 0; g < ctx->num_bands[j]; g++) { |
| 331 | i += band_sizes[g]; |
| 332 | bark = calc_bark((i-1) * line_to_frequency); |
| 333 | coeffs[g].barks = (bark + prev) / 2.0; |
| 334 | prev = bark; |
| 335 | } |
| 336 | for (g = 0; g < ctx->num_bands[j] - 1; g++) { |
| 337 | AacPsyCoeffs *coeff = &coeffs[g]; |
| 338 | float bark_width = coeffs[g+1].barks - coeffs->barks; |
| 339 | coeff->spread_low[0] = pow(10.0, -bark_width * PSY_3GPP_THR_SPREAD_LOW); |
| 340 | coeff->spread_hi [0] = pow(10.0, -bark_width * PSY_3GPP_THR_SPREAD_HI); |
| 341 | coeff->spread_low[1] = pow(10.0, -bark_width * en_spread_low); |
| 342 | coeff->spread_hi [1] = pow(10.0, -bark_width * en_spread_hi); |
| 343 | pe_min = bark_pe * bark_width; |
| 344 | minsnr = exp2(pe_min / band_sizes[g]) - 1.5f; |
| 345 | coeff->min_snr = av_clipf(1.0f / minsnr, PSY_SNR_25DB, PSY_SNR_1DB); |
| 346 | } |
| 347 | start = 0; |
| 348 | for (g = 0; g < ctx->num_bands[j]; g++) { |
| 349 | minscale = ath(start * line_to_frequency, ATH_ADD); |
| 350 | for (i = 1; i < band_sizes[g]; i++) |
| 351 | minscale = FFMIN(minscale, ath((start + i) * line_to_frequency, ATH_ADD)); |
| 352 | coeffs[g].ath = minscale - minath; |
| 353 | start += band_sizes[g]; |
| 354 | } |
| 355 | } |
| 356 | |
| 357 | pctx->ch = av_mallocz_array(ctx->avctx->channels, sizeof(AacPsyChannel)); |
| 358 | |
| 359 | lame_window_init(pctx, ctx->avctx); |
| 360 | |
| 361 | return 0; |
| 362 | } |
| 363 | |
| 364 | /** |
| 365 | * IIR filter used in block switching decision |
| 366 | */ |
| 367 | static float iir_filter(int in, float state[2]) |
| 368 | { |
| 369 | float ret; |
| 370 | |
| 371 | ret = 0.7548f * (in - state[0]) + 0.5095f * state[1]; |
| 372 | state[0] = in; |
| 373 | state[1] = ret; |
| 374 | return ret; |
| 375 | } |
| 376 | |
| 377 | /** |
| 378 | * window grouping information stored as bits (0 - new group, 1 - group continues) |
| 379 | */ |
| 380 | static const uint8_t window_grouping[9] = { |
| 381 | 0xB6, 0x6C, 0xD8, 0xB2, 0x66, 0xC6, 0x96, 0x36, 0x36 |
| 382 | }; |
| 383 | |
| 384 | /** |
| 385 | * Tell encoder which window types to use. |
| 386 | * @see 3GPP TS26.403 5.4.1 "Blockswitching" |
| 387 | */ |
| 388 | static av_unused FFPsyWindowInfo psy_3gpp_window(FFPsyContext *ctx, |
| 389 | const int16_t *audio, |
| 390 | const int16_t *la, |
| 391 | int channel, int prev_type) |
| 392 | { |
| 393 | int i, j; |
| 394 | int br = ctx->avctx->bit_rate / ctx->avctx->channels; |
| 395 | int attack_ratio = br <= 16000 ? 18 : 10; |
| 396 | AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data; |
| 397 | AacPsyChannel *pch = &pctx->ch[channel]; |
| 398 | uint8_t grouping = 0; |
| 399 | int next_type = pch->next_window_seq; |
| 400 | FFPsyWindowInfo wi = { { 0 } }; |
| 401 | |
| 402 | if (la) { |
| 403 | float s[8], v; |
| 404 | int switch_to_eight = 0; |
| 405 | float sum = 0.0, sum2 = 0.0; |
| 406 | int attack_n = 0; |
| 407 | int stay_short = 0; |
| 408 | for (i = 0; i < 8; i++) { |
| 409 | for (j = 0; j < 128; j++) { |
| 410 | v = iir_filter(la[i*128+j], pch->iir_state); |
| 411 | sum += v*v; |
| 412 | } |
| 413 | s[i] = sum; |
| 414 | sum2 += sum; |
| 415 | } |
| 416 | for (i = 0; i < 8; i++) { |
| 417 | if (s[i] > pch->win_energy * attack_ratio) { |
| 418 | attack_n = i + 1; |
| 419 | switch_to_eight = 1; |
| 420 | break; |
| 421 | } |
| 422 | } |
| 423 | pch->win_energy = pch->win_energy*7/8 + sum2/64; |
| 424 | |
| 425 | wi.window_type[1] = prev_type; |
| 426 | switch (prev_type) { |
| 427 | case ONLY_LONG_SEQUENCE: |
| 428 | wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE; |
| 429 | next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE; |
| 430 | break; |
| 431 | case LONG_START_SEQUENCE: |
| 432 | wi.window_type[0] = EIGHT_SHORT_SEQUENCE; |
| 433 | grouping = pch->next_grouping; |
| 434 | next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE; |
| 435 | break; |
| 436 | case LONG_STOP_SEQUENCE: |
| 437 | wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE; |
| 438 | next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE; |
| 439 | break; |
| 440 | case EIGHT_SHORT_SEQUENCE: |
| 441 | stay_short = next_type == EIGHT_SHORT_SEQUENCE || switch_to_eight; |
| 442 | wi.window_type[0] = stay_short ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE; |
| 443 | grouping = next_type == EIGHT_SHORT_SEQUENCE ? pch->next_grouping : 0; |
| 444 | next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE; |
| 445 | break; |
| 446 | } |
| 447 | |
| 448 | pch->next_grouping = window_grouping[attack_n]; |
| 449 | pch->next_window_seq = next_type; |
| 450 | } else { |
| 451 | for (i = 0; i < 3; i++) |
| 452 | wi.window_type[i] = prev_type; |
| 453 | grouping = (prev_type == EIGHT_SHORT_SEQUENCE) ? window_grouping[0] : 0; |
| 454 | } |
| 455 | |
| 456 | wi.window_shape = 1; |
| 457 | if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) { |
| 458 | wi.num_windows = 1; |
| 459 | wi.grouping[0] = 1; |
| 460 | } else { |
| 461 | int lastgrp = 0; |
| 462 | wi.num_windows = 8; |
| 463 | for (i = 0; i < 8; i++) { |
| 464 | if (!((grouping >> i) & 1)) |
| 465 | lastgrp = i; |
| 466 | wi.grouping[lastgrp]++; |
| 467 | } |
| 468 | } |
| 469 | |
| 470 | return wi; |
| 471 | } |
| 472 | |
| 473 | /* 5.6.1.2 "Calculation of Bit Demand" */ |
| 474 | static int calc_bit_demand(AacPsyContext *ctx, float pe, int bits, int size, |
| 475 | int short_window) |
| 476 | { |
| 477 | const float bitsave_slope = short_window ? PSY_3GPP_SAVE_SLOPE_S : PSY_3GPP_SAVE_SLOPE_L; |
| 478 | const float bitsave_add = short_window ? PSY_3GPP_SAVE_ADD_S : PSY_3GPP_SAVE_ADD_L; |
| 479 | const float bitspend_slope = short_window ? PSY_3GPP_SPEND_SLOPE_S : PSY_3GPP_SPEND_SLOPE_L; |
| 480 | const float bitspend_add = short_window ? PSY_3GPP_SPEND_ADD_S : PSY_3GPP_SPEND_ADD_L; |
| 481 | const float clip_low = short_window ? PSY_3GPP_CLIP_LO_S : PSY_3GPP_CLIP_LO_L; |
| 482 | const float clip_high = short_window ? PSY_3GPP_CLIP_HI_S : PSY_3GPP_CLIP_HI_L; |
| 483 | float clipped_pe, bit_save, bit_spend, bit_factor, fill_level; |
| 484 | |
| 485 | ctx->fill_level += ctx->frame_bits - bits; |
| 486 | ctx->fill_level = av_clip(ctx->fill_level, 0, size); |
| 487 | fill_level = av_clipf((float)ctx->fill_level / size, clip_low, clip_high); |
| 488 | clipped_pe = av_clipf(pe, ctx->pe.min, ctx->pe.max); |
| 489 | bit_save = (fill_level + bitsave_add) * bitsave_slope; |
| 490 | assert(bit_save <= 0.3f && bit_save >= -0.05000001f); |
| 491 | bit_spend = (fill_level + bitspend_add) * bitspend_slope; |
| 492 | assert(bit_spend <= 0.5f && bit_spend >= -0.1f); |
| 493 | /* The bit factor graph in the spec is obviously incorrect. |
| 494 | * bit_spend + ((bit_spend - bit_spend))... |
| 495 | * The reference encoder subtracts everything from 1, but also seems incorrect. |
| 496 | * 1 - bit_save + ((bit_spend + bit_save))... |
| 497 | * Hopefully below is correct. |
| 498 | */ |
| 499 | bit_factor = 1.0f - bit_save + ((bit_spend - bit_save) / (ctx->pe.max - ctx->pe.min)) * (clipped_pe - ctx->pe.min); |
| 500 | /* NOTE: The reference encoder attempts to center pe max/min around the current pe. */ |
| 501 | ctx->pe.max = FFMAX(pe, ctx->pe.max); |
| 502 | ctx->pe.min = FFMIN(pe, ctx->pe.min); |
| 503 | |
| 504 | return FFMIN(ctx->frame_bits * bit_factor, ctx->frame_bits + size - bits); |
| 505 | } |
| 506 | |
| 507 | static float calc_pe_3gpp(AacPsyBand *band) |
| 508 | { |
| 509 | float pe, a; |
| 510 | |
| 511 | band->pe = 0.0f; |
| 512 | band->pe_const = 0.0f; |
| 513 | band->active_lines = 0.0f; |
| 514 | if (band->energy > band->thr) { |
| 515 | a = log2f(band->energy); |
| 516 | pe = a - log2f(band->thr); |
| 517 | band->active_lines = band->nz_lines; |
| 518 | if (pe < PSY_3GPP_C1) { |
| 519 | pe = pe * PSY_3GPP_C3 + PSY_3GPP_C2; |
| 520 | a = a * PSY_3GPP_C3 + PSY_3GPP_C2; |
| 521 | band->active_lines *= PSY_3GPP_C3; |
| 522 | } |
| 523 | band->pe = pe * band->nz_lines; |
| 524 | band->pe_const = a * band->nz_lines; |
| 525 | } |
| 526 | |
| 527 | return band->pe; |
| 528 | } |
| 529 | |
| 530 | static float calc_reduction_3gpp(float a, float desired_pe, float pe, |
| 531 | float active_lines) |
| 532 | { |
| 533 | float thr_avg, reduction; |
| 534 | |
| 535 | if(active_lines == 0.0) |
| 536 | return 0; |
| 537 | |
| 538 | thr_avg = exp2f((a - pe) / (4.0f * active_lines)); |
| 539 | reduction = exp2f((a - desired_pe) / (4.0f * active_lines)) - thr_avg; |
| 540 | |
| 541 | return FFMAX(reduction, 0.0f); |
| 542 | } |
| 543 | |
| 544 | static float calc_reduced_thr_3gpp(AacPsyBand *band, float min_snr, |
| 545 | float reduction) |
| 546 | { |
| 547 | float thr = band->thr; |
| 548 | |
| 549 | if (band->energy > thr) { |
| 550 | thr = sqrtf(thr); |
| 551 | thr = sqrtf(thr) + reduction; |
| 552 | thr *= thr; |
| 553 | thr *= thr; |
| 554 | |
| 555 | /* This deviates from the 3GPP spec to match the reference encoder. |
| 556 | * It performs min(thr_reduced, max(thr, energy/min_snr)) only for bands |
| 557 | * that have hole avoidance on (active or inactive). It always reduces the |
| 558 | * threshold of bands with hole avoidance off. |
| 559 | */ |
| 560 | if (thr > band->energy * min_snr && band->avoid_holes != PSY_3GPP_AH_NONE) { |
| 561 | thr = FFMAX(band->thr, band->energy * min_snr); |
| 562 | band->avoid_holes = PSY_3GPP_AH_ACTIVE; |
| 563 | } |
| 564 | } |
| 565 | |
| 566 | return thr; |
| 567 | } |
| 568 | |
| 569 | #ifndef calc_thr_3gpp |
| 570 | static void calc_thr_3gpp(const FFPsyWindowInfo *wi, const int num_bands, AacPsyChannel *pch, |
| 571 | const uint8_t *band_sizes, const float *coefs) |
| 572 | { |
| 573 | int i, w, g; |
| 574 | int start = 0; |
| 575 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 576 | for (g = 0; g < num_bands; g++) { |
| 577 | AacPsyBand *band = &pch->band[w+g]; |
| 578 | |
| 579 | float form_factor = 0.0f; |
| 580 | float Temp; |
| 581 | band->energy = 0.0f; |
| 582 | for (i = 0; i < band_sizes[g]; i++) { |
| 583 | band->energy += coefs[start+i] * coefs[start+i]; |
| 584 | form_factor += sqrtf(fabs(coefs[start+i])); |
| 585 | } |
| 586 | Temp = band->energy > 0 ? sqrtf((float)band_sizes[g] / band->energy) : 0; |
| 587 | band->thr = band->energy * 0.001258925f; |
| 588 | band->nz_lines = form_factor * sqrtf(Temp); |
| 589 | |
| 590 | start += band_sizes[g]; |
| 591 | } |
| 592 | } |
| 593 | } |
| 594 | #endif /* calc_thr_3gpp */ |
| 595 | |
| 596 | #ifndef psy_hp_filter |
| 597 | static void psy_hp_filter(const float *firbuf, float *hpfsmpl, const float *psy_fir_coeffs) |
| 598 | { |
| 599 | int i, j; |
| 600 | for (i = 0; i < AAC_BLOCK_SIZE_LONG; i++) { |
| 601 | float sum1, sum2; |
| 602 | sum1 = firbuf[i + (PSY_LAME_FIR_LEN - 1) / 2]; |
| 603 | sum2 = 0.0; |
| 604 | for (j = 0; j < ((PSY_LAME_FIR_LEN - 1) / 2) - 1; j += 2) { |
| 605 | sum1 += psy_fir_coeffs[j] * (firbuf[i + j] + firbuf[i + PSY_LAME_FIR_LEN - j]); |
| 606 | sum2 += psy_fir_coeffs[j + 1] * (firbuf[i + j + 1] + firbuf[i + PSY_LAME_FIR_LEN - j - 1]); |
| 607 | } |
| 608 | /* NOTE: The LAME psymodel expects it's input in the range -32768 to 32768. |
| 609 | * Tuning this for normalized floats would be difficult. */ |
| 610 | hpfsmpl[i] = (sum1 + sum2) * 32768.0f; |
| 611 | } |
| 612 | } |
| 613 | #endif /* psy_hp_filter */ |
| 614 | |
| 615 | /** |
| 616 | * Calculate band thresholds as suggested in 3GPP TS26.403 |
| 617 | */ |
| 618 | static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel, |
| 619 | const float *coefs, const FFPsyWindowInfo *wi) |
| 620 | { |
| 621 | AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data; |
| 622 | AacPsyChannel *pch = &pctx->ch[channel]; |
| 623 | int i, w, g; |
| 624 | float desired_bits, desired_pe, delta_pe, reduction= NAN, spread_en[128] = {0}; |
| 625 | float a = 0.0f, active_lines = 0.0f, norm_fac = 0.0f; |
| 626 | float pe = pctx->chan_bitrate > 32000 ? 0.0f : FFMAX(50.0f, 100.0f - pctx->chan_bitrate * 100.0f / 32000.0f); |
| 627 | const int num_bands = ctx->num_bands[wi->num_windows == 8]; |
| 628 | const uint8_t *band_sizes = ctx->bands[wi->num_windows == 8]; |
| 629 | AacPsyCoeffs *coeffs = pctx->psy_coef[wi->num_windows == 8]; |
| 630 | const float avoid_hole_thr = wi->num_windows == 8 ? PSY_3GPP_AH_THR_SHORT : PSY_3GPP_AH_THR_LONG; |
| 631 | |
| 632 | //calculate energies, initial thresholds and related values - 5.4.2 "Threshold Calculation" |
| 633 | calc_thr_3gpp(wi, num_bands, pch, band_sizes, coefs); |
| 634 | |
| 635 | //modify thresholds and energies - spread, threshold in quiet, pre-echo control |
| 636 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 637 | AacPsyBand *bands = &pch->band[w]; |
| 638 | |
| 639 | /* 5.4.2.3 "Spreading" & 5.4.3 "Spread Energy Calculation" */ |
| 640 | spread_en[0] = bands[0].energy; |
| 641 | for (g = 1; g < num_bands; g++) { |
| 642 | bands[g].thr = FFMAX(bands[g].thr, bands[g-1].thr * coeffs[g].spread_hi[0]); |
| 643 | spread_en[w+g] = FFMAX(bands[g].energy, spread_en[w+g-1] * coeffs[g].spread_hi[1]); |
| 644 | } |
| 645 | for (g = num_bands - 2; g >= 0; g--) { |
| 646 | bands[g].thr = FFMAX(bands[g].thr, bands[g+1].thr * coeffs[g].spread_low[0]); |
| 647 | spread_en[w+g] = FFMAX(spread_en[w+g], spread_en[w+g+1] * coeffs[g].spread_low[1]); |
| 648 | } |
| 649 | //5.4.2.4 "Threshold in quiet" |
| 650 | for (g = 0; g < num_bands; g++) { |
| 651 | AacPsyBand *band = &bands[g]; |
| 652 | |
| 653 | band->thr_quiet = band->thr = FFMAX(band->thr, coeffs[g].ath); |
| 654 | //5.4.2.5 "Pre-echo control" |
| 655 | if (!(wi->window_type[0] == LONG_STOP_SEQUENCE || (wi->window_type[1] == LONG_START_SEQUENCE && !w))) |
| 656 | band->thr = FFMAX(PSY_3GPP_RPEMIN*band->thr, FFMIN(band->thr, |
| 657 | PSY_3GPP_RPELEV*pch->prev_band[w+g].thr_quiet)); |
| 658 | |
| 659 | /* 5.6.1.3.1 "Preparatory steps of the perceptual entropy calculation" */ |
| 660 | pe += calc_pe_3gpp(band); |
| 661 | a += band->pe_const; |
| 662 | active_lines += band->active_lines; |
| 663 | |
| 664 | /* 5.6.1.3.3 "Selection of the bands for avoidance of holes" */ |
| 665 | if (spread_en[w+g] * avoid_hole_thr > band->energy || coeffs[g].min_snr > 1.0f) |
| 666 | band->avoid_holes = PSY_3GPP_AH_NONE; |
| 667 | else |
| 668 | band->avoid_holes = PSY_3GPP_AH_INACTIVE; |
| 669 | } |
| 670 | } |
| 671 | |
| 672 | /* 5.6.1.3.2 "Calculation of the desired perceptual entropy" */ |
| 673 | ctx->ch[channel].entropy = pe; |
| 674 | desired_bits = calc_bit_demand(pctx, pe, ctx->bitres.bits, ctx->bitres.size, wi->num_windows == 8); |
| 675 | desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits); |
| 676 | /* NOTE: PE correction is kept simple. During initial testing it had very |
| 677 | * little effect on the final bitrate. Probably a good idea to come |
| 678 | * back and do more testing later. |
| 679 | */ |
| 680 | if (ctx->bitres.bits > 0) |
| 681 | desired_pe *= av_clipf(pctx->pe.previous / PSY_3GPP_BITS_TO_PE(ctx->bitres.bits), |
| 682 | 0.85f, 1.15f); |
| 683 | pctx->pe.previous = PSY_3GPP_BITS_TO_PE(desired_bits); |
| 684 | |
| 685 | if (desired_pe < pe) { |
| 686 | /* 5.6.1.3.4 "First Estimation of the reduction value" */ |
| 687 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 688 | reduction = calc_reduction_3gpp(a, desired_pe, pe, active_lines); |
| 689 | pe = 0.0f; |
| 690 | a = 0.0f; |
| 691 | active_lines = 0.0f; |
| 692 | for (g = 0; g < num_bands; g++) { |
| 693 | AacPsyBand *band = &pch->band[w+g]; |
| 694 | |
| 695 | band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction); |
| 696 | /* recalculate PE */ |
| 697 | pe += calc_pe_3gpp(band); |
| 698 | a += band->pe_const; |
| 699 | active_lines += band->active_lines; |
| 700 | } |
| 701 | } |
| 702 | |
| 703 | /* 5.6.1.3.5 "Second Estimation of the reduction value" */ |
| 704 | for (i = 0; i < 2; i++) { |
| 705 | float pe_no_ah = 0.0f, desired_pe_no_ah; |
| 706 | active_lines = a = 0.0f; |
| 707 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 708 | for (g = 0; g < num_bands; g++) { |
| 709 | AacPsyBand *band = &pch->band[w+g]; |
| 710 | |
| 711 | if (band->avoid_holes != PSY_3GPP_AH_ACTIVE) { |
| 712 | pe_no_ah += band->pe; |
| 713 | a += band->pe_const; |
| 714 | active_lines += band->active_lines; |
| 715 | } |
| 716 | } |
| 717 | } |
| 718 | desired_pe_no_ah = FFMAX(desired_pe - (pe - pe_no_ah), 0.0f); |
| 719 | if (active_lines > 0.0f) |
| 720 | reduction += calc_reduction_3gpp(a, desired_pe_no_ah, pe_no_ah, active_lines); |
| 721 | |
| 722 | pe = 0.0f; |
| 723 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 724 | for (g = 0; g < num_bands; g++) { |
| 725 | AacPsyBand *band = &pch->band[w+g]; |
| 726 | |
| 727 | if (active_lines > 0.0f) |
| 728 | band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction); |
| 729 | pe += calc_pe_3gpp(band); |
| 730 | band->norm_fac = band->active_lines / band->thr; |
| 731 | norm_fac += band->norm_fac; |
| 732 | } |
| 733 | } |
| 734 | delta_pe = desired_pe - pe; |
| 735 | if (fabs(delta_pe) > 0.05f * desired_pe) |
| 736 | break; |
| 737 | } |
| 738 | |
| 739 | if (pe < 1.15f * desired_pe) { |
| 740 | /* 6.6.1.3.6 "Final threshold modification by linearization" */ |
| 741 | norm_fac = 1.0f / norm_fac; |
| 742 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 743 | for (g = 0; g < num_bands; g++) { |
| 744 | AacPsyBand *band = &pch->band[w+g]; |
| 745 | |
| 746 | if (band->active_lines > 0.5f) { |
| 747 | float delta_sfb_pe = band->norm_fac * norm_fac * delta_pe; |
| 748 | float thr = band->thr; |
| 749 | |
| 750 | thr *= exp2f(delta_sfb_pe / band->active_lines); |
| 751 | if (thr > coeffs[g].min_snr * band->energy && band->avoid_holes == PSY_3GPP_AH_INACTIVE) |
| 752 | thr = FFMAX(band->thr, coeffs[g].min_snr * band->energy); |
| 753 | band->thr = thr; |
| 754 | } |
| 755 | } |
| 756 | } |
| 757 | } else { |
| 758 | /* 5.6.1.3.7 "Further perceptual entropy reduction" */ |
| 759 | g = num_bands; |
| 760 | while (pe > desired_pe && g--) { |
| 761 | for (w = 0; w < wi->num_windows*16; w+= 16) { |
| 762 | AacPsyBand *band = &pch->band[w+g]; |
| 763 | if (band->avoid_holes != PSY_3GPP_AH_NONE && coeffs[g].min_snr < PSY_SNR_1DB) { |
| 764 | coeffs[g].min_snr = PSY_SNR_1DB; |
| 765 | band->thr = band->energy * PSY_SNR_1DB; |
| 766 | pe += band->active_lines * 1.5f - band->pe; |
| 767 | } |
| 768 | } |
| 769 | } |
| 770 | /* TODO: allow more holes (unused without mid/side) */ |
| 771 | } |
| 772 | } |
| 773 | |
| 774 | for (w = 0; w < wi->num_windows*16; w += 16) { |
| 775 | for (g = 0; g < num_bands; g++) { |
| 776 | AacPsyBand *band = &pch->band[w+g]; |
| 777 | FFPsyBand *psy_band = &ctx->ch[channel].psy_bands[w+g]; |
| 778 | |
| 779 | psy_band->threshold = band->thr; |
| 780 | psy_band->energy = band->energy; |
| 781 | } |
| 782 | } |
| 783 | |
| 784 | memcpy(pch->prev_band, pch->band, sizeof(pch->band)); |
| 785 | } |
| 786 | |
| 787 | static void psy_3gpp_analyze(FFPsyContext *ctx, int channel, |
| 788 | const float **coeffs, const FFPsyWindowInfo *wi) |
| 789 | { |
| 790 | int ch; |
| 791 | FFPsyChannelGroup *group = ff_psy_find_group(ctx, channel); |
| 792 | |
| 793 | for (ch = 0; ch < group->num_ch; ch++) |
| 794 | psy_3gpp_analyze_channel(ctx, channel + ch, coeffs[ch], &wi[ch]); |
| 795 | } |
| 796 | |
| 797 | static av_cold void psy_3gpp_end(FFPsyContext *apc) |
| 798 | { |
| 799 | AacPsyContext *pctx = (AacPsyContext*) apc->model_priv_data; |
| 800 | av_freep(&pctx->ch); |
| 801 | av_freep(&apc->model_priv_data); |
| 802 | } |
| 803 | |
| 804 | static void lame_apply_block_type(AacPsyChannel *ctx, FFPsyWindowInfo *wi, int uselongblock) |
| 805 | { |
| 806 | int blocktype = ONLY_LONG_SEQUENCE; |
| 807 | if (uselongblock) { |
| 808 | if (ctx->next_window_seq == EIGHT_SHORT_SEQUENCE) |
| 809 | blocktype = LONG_STOP_SEQUENCE; |
| 810 | } else { |
| 811 | blocktype = EIGHT_SHORT_SEQUENCE; |
| 812 | if (ctx->next_window_seq == ONLY_LONG_SEQUENCE) |
| 813 | ctx->next_window_seq = LONG_START_SEQUENCE; |
| 814 | if (ctx->next_window_seq == LONG_STOP_SEQUENCE) |
| 815 | ctx->next_window_seq = EIGHT_SHORT_SEQUENCE; |
| 816 | } |
| 817 | |
| 818 | wi->window_type[0] = ctx->next_window_seq; |
| 819 | ctx->next_window_seq = blocktype; |
| 820 | } |
| 821 | |
| 822 | static FFPsyWindowInfo psy_lame_window(FFPsyContext *ctx, const float *audio, |
| 823 | const float *la, int channel, int prev_type) |
| 824 | { |
| 825 | AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data; |
| 826 | AacPsyChannel *pch = &pctx->ch[channel]; |
| 827 | int grouping = 0; |
| 828 | int uselongblock = 1; |
| 829 | int attacks[AAC_NUM_BLOCKS_SHORT + 1] = { 0 }; |
| 830 | int i; |
| 831 | FFPsyWindowInfo wi = { { 0 } }; |
| 832 | |
| 833 | if (la) { |
| 834 | float hpfsmpl[AAC_BLOCK_SIZE_LONG]; |
| 835 | float const *pf = hpfsmpl; |
| 836 | float attack_intensity[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS]; |
| 837 | float energy_subshort[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS]; |
| 838 | float energy_short[AAC_NUM_BLOCKS_SHORT + 1] = { 0 }; |
| 839 | const float *firbuf = la + (AAC_BLOCK_SIZE_SHORT/4 - PSY_LAME_FIR_LEN); |
| 840 | int att_sum = 0; |
| 841 | |
| 842 | /* LAME comment: apply high pass filter of fs/4 */ |
| 843 | psy_hp_filter(firbuf, hpfsmpl, psy_fir_coeffs); |
| 844 | |
| 845 | /* Calculate the energies of each sub-shortblock */ |
| 846 | for (i = 0; i < PSY_LAME_NUM_SUBBLOCKS; i++) { |
| 847 | energy_subshort[i] = pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 1) * PSY_LAME_NUM_SUBBLOCKS)]; |
| 848 | assert(pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)] > 0); |
| 849 | attack_intensity[i] = energy_subshort[i] / pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)]; |
| 850 | energy_short[0] += energy_subshort[i]; |
| 851 | } |
| 852 | |
| 853 | for (i = 0; i < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; i++) { |
| 854 | float const *const pfe = pf + AAC_BLOCK_SIZE_LONG / (AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS); |
| 855 | float p = 1.0f; |
| 856 | for (; pf < pfe; pf++) |
| 857 | p = FFMAX(p, fabsf(*pf)); |
| 858 | pch->prev_energy_subshort[i] = energy_subshort[i + PSY_LAME_NUM_SUBBLOCKS] = p; |
| 859 | energy_short[1 + i / PSY_LAME_NUM_SUBBLOCKS] += p; |
| 860 | /* NOTE: The indexes below are [i + 3 - 2] in the LAME source. |
| 861 | * Obviously the 3 and 2 have some significance, or this would be just [i + 1] |
| 862 | * (which is what we use here). What the 3 stands for is ambiguous, as it is both |
| 863 | * number of short blocks, and the number of sub-short blocks. |
| 864 | * It seems that LAME is comparing each sub-block to sub-block + 1 in the |
| 865 | * previous block. |
| 866 | */ |
| 867 | if (p > energy_subshort[i + 1]) |
| 868 | p = p / energy_subshort[i + 1]; |
| 869 | else if (energy_subshort[i + 1] > p * 10.0f) |
| 870 | p = energy_subshort[i + 1] / (p * 10.0f); |
| 871 | else |
| 872 | p = 0.0; |
| 873 | attack_intensity[i + PSY_LAME_NUM_SUBBLOCKS] = p; |
| 874 | } |
| 875 | |
| 876 | /* compare energy between sub-short blocks */ |
| 877 | for (i = 0; i < (AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS; i++) |
| 878 | if (!attacks[i / PSY_LAME_NUM_SUBBLOCKS]) |
| 879 | if (attack_intensity[i] > pch->attack_threshold) |
| 880 | attacks[i / PSY_LAME_NUM_SUBBLOCKS] = (i % PSY_LAME_NUM_SUBBLOCKS) + 1; |
| 881 | |
| 882 | /* should have energy change between short blocks, in order to avoid periodic signals */ |
| 883 | /* Good samples to show the effect are Trumpet test songs */ |
| 884 | /* GB: tuned (1) to avoid too many short blocks for test sample TRUMPET */ |
| 885 | /* RH: tuned (2) to let enough short blocks through for test sample FSOL and SNAPS */ |
| 886 | for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++) { |
| 887 | float const u = energy_short[i - 1]; |
| 888 | float const v = energy_short[i]; |
| 889 | float const m = FFMAX(u, v); |
| 890 | if (m < 40000) { /* (2) */ |
| 891 | if (u < 1.7f * v && v < 1.7f * u) { /* (1) */ |
| 892 | if (i == 1 && attacks[0] < attacks[i]) |
| 893 | attacks[0] = 0; |
| 894 | attacks[i] = 0; |
| 895 | } |
| 896 | } |
| 897 | att_sum += attacks[i]; |
| 898 | } |
| 899 | |
| 900 | if (attacks[0] <= pch->prev_attack) |
| 901 | attacks[0] = 0; |
| 902 | |
| 903 | att_sum += attacks[0]; |
| 904 | /* 3 below indicates the previous attack happened in the last sub-block of the previous sequence */ |
| 905 | if (pch->prev_attack == 3 || att_sum) { |
| 906 | uselongblock = 0; |
| 907 | |
| 908 | for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++) |
| 909 | if (attacks[i] && attacks[i-1]) |
| 910 | attacks[i] = 0; |
| 911 | } |
| 912 | } else { |
| 913 | /* We have no lookahead info, so just use same type as the previous sequence. */ |
| 914 | uselongblock = !(prev_type == EIGHT_SHORT_SEQUENCE); |
| 915 | } |
| 916 | |
| 917 | lame_apply_block_type(pch, &wi, uselongblock); |
| 918 | |
| 919 | wi.window_type[1] = prev_type; |
| 920 | if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) { |
| 921 | wi.num_windows = 1; |
| 922 | wi.grouping[0] = 1; |
| 923 | if (wi.window_type[0] == LONG_START_SEQUENCE) |
| 924 | wi.window_shape = 0; |
| 925 | else |
| 926 | wi.window_shape = 1; |
| 927 | } else { |
| 928 | int lastgrp = 0; |
| 929 | |
| 930 | wi.num_windows = 8; |
| 931 | wi.window_shape = 0; |
| 932 | for (i = 0; i < 8; i++) { |
| 933 | if (!((pch->next_grouping >> i) & 1)) |
| 934 | lastgrp = i; |
| 935 | wi.grouping[lastgrp]++; |
| 936 | } |
| 937 | } |
| 938 | |
| 939 | /* Determine grouping, based on the location of the first attack, and save for |
| 940 | * the next frame. |
| 941 | * FIXME: Move this to analysis. |
| 942 | * TODO: Tune groupings depending on attack location |
| 943 | * TODO: Handle more than one attack in a group |
| 944 | */ |
| 945 | for (i = 0; i < 9; i++) { |
| 946 | if (attacks[i]) { |
| 947 | grouping = i; |
| 948 | break; |
| 949 | } |
| 950 | } |
| 951 | pch->next_grouping = window_grouping[grouping]; |
| 952 | |
| 953 | pch->prev_attack = attacks[8]; |
| 954 | |
| 955 | return wi; |
| 956 | } |
| 957 | |
| 958 | const FFPsyModel ff_aac_psy_model = |
| 959 | { |
| 960 | .name = "3GPP TS 26.403-inspired model", |
| 961 | .init = psy_3gpp_init, |
| 962 | .window = psy_lame_window, |
| 963 | .analyze = psy_3gpp_analyze, |
| 964 | .end = psy_3gpp_end, |
| 965 | }; |