render.cc (29715B)
1 // Copyright (c) the JPEG XL Project Authors. All rights reserved. 2 // 3 // Use of this source code is governed by a BSD-style 4 // license that can be found in the LICENSE file. 5 6 #include "lib/jpegli/render.h" 7 8 #include <array> 9 #include <cmath> 10 #include <cstddef> 11 #include <cstdint> 12 #include <cstring> 13 #include <vector> 14 15 #include "lib/jpegli/color_quantize.h" 16 #include "lib/jpegli/color_transform.h" 17 #include "lib/jpegli/decode_internal.h" 18 #include "lib/jpegli/error.h" 19 #include "lib/jpegli/idct.h" 20 #include "lib/jpegli/upsample.h" 21 #include "lib/jxl/base/byte_order.h" 22 #include "lib/jxl/base/compiler_specific.h" 23 24 #ifdef MEMORY_SANITIZER 25 #define JXL_MEMORY_SANITIZER 1 26 #elif defined(__has_feature) 27 #if __has_feature(memory_sanitizer) 28 #define JXL_MEMORY_SANITIZER 1 29 #else 30 #define JXL_MEMORY_SANITIZER 0 31 #endif 32 #else 33 #define JXL_MEMORY_SANITIZER 0 34 #endif 35 36 #if JXL_MEMORY_SANITIZER 37 #include "sanitizer/msan_interface.h" 38 #endif 39 40 #undef HWY_TARGET_INCLUDE 41 #define HWY_TARGET_INCLUDE "lib/jpegli/render.cc" 42 #include <hwy/foreach_target.h> 43 #include <hwy/highway.h> 44 45 HWY_BEFORE_NAMESPACE(); 46 namespace jpegli { 47 namespace HWY_NAMESPACE { 48 49 // These templates are not found via ADL. 50 using hwy::HWY_NAMESPACE::Abs; 51 using hwy::HWY_NAMESPACE::Add; 52 using hwy::HWY_NAMESPACE::Clamp; 53 using hwy::HWY_NAMESPACE::Gt; 54 using hwy::HWY_NAMESPACE::IfThenElseZero; 55 using hwy::HWY_NAMESPACE::Mul; 56 using hwy::HWY_NAMESPACE::NearestInt; 57 using hwy::HWY_NAMESPACE::Or; 58 using hwy::HWY_NAMESPACE::Rebind; 59 using hwy::HWY_NAMESPACE::ShiftLeftSame; 60 using hwy::HWY_NAMESPACE::ShiftRightSame; 61 using hwy::HWY_NAMESPACE::Vec; 62 using D = HWY_FULL(float); 63 using DI = HWY_FULL(int32_t); 64 constexpr D d; 65 constexpr DI di; 66 67 void GatherBlockStats(const int16_t* JXL_RESTRICT coeffs, 68 const size_t coeffs_size, int32_t* JXL_RESTRICT nonzeros, 69 int32_t* JXL_RESTRICT sumabs) { 70 for (size_t i = 0; i < coeffs_size; i += Lanes(d)) { 71 size_t k = i % DCTSIZE2; 72 const Rebind<int16_t, DI> di16; 73 const Vec<DI> coeff = PromoteTo(di, Load(di16, coeffs + i)); 74 const auto abs_coeff = Abs(coeff); 75 const auto not_0 = Gt(abs_coeff, Zero(di)); 76 const auto nzero = IfThenElseZero(not_0, Set(di, 1)); 77 Store(Add(nzero, Load(di, nonzeros + k)), di, nonzeros + k); 78 Store(Add(abs_coeff, Load(di, sumabs + k)), di, sumabs + k); 79 } 80 } 81 82 void DecenterRow(float* row, size_t xsize) { 83 const HWY_CAPPED(float, 8) df; 84 const auto c128 = Set(df, 128.0f / 255); 85 for (size_t x = 0; x < xsize; x += Lanes(df)) { 86 Store(Add(Load(df, row + x), c128), df, row + x); 87 } 88 } 89 90 void DitherRow(j_decompress_ptr cinfo, float* row, int c, size_t y, 91 size_t xsize) { 92 jpeg_decomp_master* m = cinfo->master; 93 if (!m->dither_[c]) return; 94 const float* dither_row = 95 &m->dither_[c][(y & m->dither_mask_) * m->dither_size_]; 96 for (size_t x = 0; x < xsize; ++x) { 97 row[x] += dither_row[x & m->dither_mask_]; 98 } 99 } 100 101 template <typename T> 102 void StoreUnsignedRow(float* JXL_RESTRICT input[], size_t x0, size_t len, 103 size_t num_channels, float multiplier, T* output) { 104 const HWY_CAPPED(float, 8) d; 105 auto zero = Zero(d); 106 auto mul = Set(d, multiplier); 107 const Rebind<T, decltype(d)> du; 108 #if JXL_MEMORY_SANITIZER 109 const size_t padding = hwy::RoundUpTo(len, Lanes(d)) - len; 110 for (size_t c = 0; c < num_channels; ++c) { 111 __msan_unpoison(input[c] + x0 + len, sizeof(input[c][0]) * padding); 112 } 113 #endif 114 if (num_channels == 1) { 115 for (size_t i = 0; i < len; i += Lanes(d)) { 116 auto v0 = Clamp(zero, Mul(LoadU(d, &input[0][x0 + i]), mul), mul); 117 StoreU(DemoteTo(du, NearestInt(v0)), du, &output[i]); 118 } 119 } else if (num_channels == 2) { 120 for (size_t i = 0; i < len; i += Lanes(d)) { 121 auto v0 = Clamp(zero, Mul(LoadU(d, &input[0][x0 + i]), mul), mul); 122 auto v1 = Clamp(zero, Mul(LoadU(d, &input[1][x0 + i]), mul), mul); 123 StoreInterleaved2(DemoteTo(du, NearestInt(v0)), 124 DemoteTo(du, NearestInt(v1)), du, &output[2 * i]); 125 } 126 } else if (num_channels == 3) { 127 for (size_t i = 0; i < len; i += Lanes(d)) { 128 auto v0 = Clamp(zero, Mul(LoadU(d, &input[0][x0 + i]), mul), mul); 129 auto v1 = Clamp(zero, Mul(LoadU(d, &input[1][x0 + i]), mul), mul); 130 auto v2 = Clamp(zero, Mul(LoadU(d, &input[2][x0 + i]), mul), mul); 131 StoreInterleaved3(DemoteTo(du, NearestInt(v0)), 132 DemoteTo(du, NearestInt(v1)), 133 DemoteTo(du, NearestInt(v2)), du, &output[3 * i]); 134 } 135 } else if (num_channels == 4) { 136 for (size_t i = 0; i < len; i += Lanes(d)) { 137 auto v0 = Clamp(zero, Mul(LoadU(d, &input[0][x0 + i]), mul), mul); 138 auto v1 = Clamp(zero, Mul(LoadU(d, &input[1][x0 + i]), mul), mul); 139 auto v2 = Clamp(zero, Mul(LoadU(d, &input[2][x0 + i]), mul), mul); 140 auto v3 = Clamp(zero, Mul(LoadU(d, &input[3][x0 + i]), mul), mul); 141 StoreInterleaved4(DemoteTo(du, NearestInt(v0)), 142 DemoteTo(du, NearestInt(v1)), 143 DemoteTo(du, NearestInt(v2)), 144 DemoteTo(du, NearestInt(v3)), du, &output[4 * i]); 145 } 146 } 147 #if JXL_MEMORY_SANITIZER 148 __msan_poison(output + num_channels * len, 149 sizeof(output[0]) * num_channels * padding); 150 #endif 151 } 152 153 void StoreFloatRow(float* JXL_RESTRICT input[3], size_t x0, size_t len, 154 size_t num_channels, float* output) { 155 const HWY_CAPPED(float, 8) d; 156 if (num_channels == 1) { 157 memcpy(output, input[0] + x0, len * sizeof(output[0])); 158 } else if (num_channels == 2) { 159 for (size_t i = 0; i < len; i += Lanes(d)) { 160 StoreInterleaved2(LoadU(d, &input[0][x0 + i]), 161 LoadU(d, &input[1][x0 + i]), d, &output[2 * i]); 162 } 163 } else if (num_channels == 3) { 164 for (size_t i = 0; i < len; i += Lanes(d)) { 165 StoreInterleaved3(LoadU(d, &input[0][x0 + i]), 166 LoadU(d, &input[1][x0 + i]), 167 LoadU(d, &input[2][x0 + i]), d, &output[3 * i]); 168 } 169 } else if (num_channels == 4) { 170 for (size_t i = 0; i < len; i += Lanes(d)) { 171 StoreInterleaved4(LoadU(d, &input[0][x0 + i]), 172 LoadU(d, &input[1][x0 + i]), 173 LoadU(d, &input[2][x0 + i]), 174 LoadU(d, &input[3][x0 + i]), d, &output[4 * i]); 175 } 176 } 177 } 178 179 static constexpr float kFSWeightMR = 7.0f / 16.0f; 180 static constexpr float kFSWeightBL = 3.0f / 16.0f; 181 static constexpr float kFSWeightBM = 5.0f / 16.0f; 182 static constexpr float kFSWeightBR = 1.0f / 16.0f; 183 184 float LimitError(float error) { 185 float abserror = std::abs(error); 186 if (abserror > 48.0f) { 187 abserror = 32.0f; 188 } else if (abserror > 16.0f) { 189 abserror = 0.5f * abserror + 8.0f; 190 } 191 return error > 0.0f ? abserror : -abserror; 192 } 193 194 void WriteToOutput(j_decompress_ptr cinfo, float* JXL_RESTRICT rows[], 195 size_t xoffset, size_t len, size_t num_channels, 196 uint8_t* JXL_RESTRICT output) { 197 jpeg_decomp_master* m = cinfo->master; 198 uint8_t* JXL_RESTRICT scratch_space = m->output_scratch_; 199 if (cinfo->quantize_colors && m->quant_pass_ == 1) { 200 float* error_row[kMaxComponents]; 201 float* next_error_row[kMaxComponents]; 202 J_DITHER_MODE dither_mode = cinfo->dither_mode; 203 if (dither_mode == JDITHER_ORDERED) { 204 for (size_t c = 0; c < num_channels; ++c) { 205 DitherRow(cinfo, &rows[c][xoffset], c, cinfo->output_scanline, 206 cinfo->output_width); 207 } 208 } else if (dither_mode == JDITHER_FS) { 209 for (size_t c = 0; c < num_channels; ++c) { 210 if (cinfo->output_scanline % 2 == 0) { 211 error_row[c] = m->error_row_[c]; 212 next_error_row[c] = m->error_row_[c + kMaxComponents]; 213 } else { 214 error_row[c] = m->error_row_[c + kMaxComponents]; 215 next_error_row[c] = m->error_row_[c]; 216 } 217 memset(next_error_row[c], 0.0, cinfo->output_width * sizeof(float)); 218 } 219 } 220 const float mul = 255.0f; 221 if (dither_mode != JDITHER_FS) { 222 StoreUnsignedRow(rows, xoffset, len, num_channels, mul, scratch_space); 223 } 224 for (size_t i = 0; i < len; ++i) { 225 uint8_t* pixel = &scratch_space[num_channels * i]; 226 if (dither_mode == JDITHER_FS) { 227 for (size_t c = 0; c < num_channels; ++c) { 228 float val = rows[c][i] * mul + LimitError(error_row[c][i]); 229 pixel[c] = std::round(std::min(255.0f, std::max(0.0f, val))); 230 } 231 } 232 int index = LookupColorIndex(cinfo, pixel); 233 output[i] = index; 234 if (dither_mode == JDITHER_FS) { 235 size_t prev_i = i > 0 ? i - 1 : 0; 236 size_t next_i = i + 1 < len ? i + 1 : len - 1; 237 for (size_t c = 0; c < num_channels; ++c) { 238 float error = pixel[c] - cinfo->colormap[c][index]; 239 error_row[c][next_i] += kFSWeightMR * error; 240 next_error_row[c][prev_i] += kFSWeightBL * error; 241 next_error_row[c][i] += kFSWeightBM * error; 242 next_error_row[c][next_i] += kFSWeightBR * error; 243 } 244 } 245 } 246 } else if (m->output_data_type_ == JPEGLI_TYPE_UINT8) { 247 const float mul = 255.0; 248 StoreUnsignedRow(rows, xoffset, len, num_channels, mul, scratch_space); 249 memcpy(output, scratch_space, len * num_channels); 250 } else if (m->output_data_type_ == JPEGLI_TYPE_UINT16) { 251 const float mul = 65535.0; 252 uint16_t* tmp = reinterpret_cast<uint16_t*>(scratch_space); 253 StoreUnsignedRow(rows, xoffset, len, num_channels, mul, tmp); 254 if (m->swap_endianness_) { 255 const HWY_CAPPED(uint16_t, 8) du; 256 size_t output_len = len * num_channels; 257 for (size_t j = 0; j < output_len; j += Lanes(du)) { 258 auto v = LoadU(du, tmp + j); 259 auto vswap = Or(ShiftRightSame(v, 8), ShiftLeftSame(v, 8)); 260 StoreU(vswap, du, tmp + j); 261 } 262 } 263 memcpy(output, tmp, len * num_channels * 2); 264 } else if (m->output_data_type_ == JPEGLI_TYPE_FLOAT) { 265 float* tmp = reinterpret_cast<float*>(scratch_space); 266 StoreFloatRow(rows, xoffset, len, num_channels, tmp); 267 if (m->swap_endianness_) { 268 size_t output_len = len * num_channels; 269 for (size_t j = 0; j < output_len; ++j) { 270 tmp[j] = BSwapFloat(tmp[j]); 271 } 272 } 273 memcpy(output, tmp, len * num_channels * 4); 274 } 275 } 276 277 // NOLINTNEXTLINE(google-readability-namespace-comments) 278 } // namespace HWY_NAMESPACE 279 } // namespace jpegli 280 HWY_AFTER_NAMESPACE(); 281 282 #if HWY_ONCE 283 284 namespace jpegli { 285 286 HWY_EXPORT(GatherBlockStats); 287 HWY_EXPORT(WriteToOutput); 288 HWY_EXPORT(DecenterRow); 289 290 void GatherBlockStats(const int16_t* JXL_RESTRICT coeffs, 291 const size_t coeffs_size, int32_t* JXL_RESTRICT nonzeros, 292 int32_t* JXL_RESTRICT sumabs) { 293 HWY_DYNAMIC_DISPATCH(GatherBlockStats)(coeffs, coeffs_size, nonzeros, sumabs); 294 } 295 296 void WriteToOutput(j_decompress_ptr cinfo, float* JXL_RESTRICT rows[], 297 size_t xoffset, size_t len, size_t num_channels, 298 uint8_t* JXL_RESTRICT output) { 299 HWY_DYNAMIC_DISPATCH(WriteToOutput) 300 (cinfo, rows, xoffset, len, num_channels, output); 301 } 302 303 void DecenterRow(float* row, size_t xsize) { 304 HWY_DYNAMIC_DISPATCH(DecenterRow)(row, xsize); 305 } 306 307 bool ShouldApplyDequantBiases(j_decompress_ptr cinfo, int ci) { 308 const auto& compinfo = cinfo->comp_info[ci]; 309 return (compinfo.h_samp_factor == cinfo->max_h_samp_factor && 310 compinfo.v_samp_factor == cinfo->max_v_samp_factor); 311 } 312 313 // See the following article for the details: 314 // J. R. Price and M. Rabbani, "Dequantization bias for JPEG decompression" 315 // Proceedings International Conference on Information Technology: Coding and 316 // Computing (Cat. No.PR00540), 2000, pp. 30-35, doi: 10.1109/ITCC.2000.844179. 317 void ComputeOptimalLaplacianBiases(const int num_blocks, const int* nonzeros, 318 const int* sumabs, float* biases) { 319 for (size_t k = 1; k < DCTSIZE2; ++k) { 320 if (nonzeros[k] == 0) { 321 biases[k] = 0.5f; 322 continue; 323 } 324 // Notation adapted from the article 325 float N = num_blocks; 326 float N1 = nonzeros[k]; 327 float N0 = num_blocks - N1; 328 float S = sumabs[k]; 329 // Compute gamma from N0, N1, N, S (eq. 11), with A and B being just 330 // temporary grouping of terms. 331 float A = 4.0 * S + 2.0 * N; 332 float B = 4.0 * S - 2.0 * N1; 333 float gamma = (-1.0 * N0 + std::sqrt(N0 * N0 * 1.0 + A * B)) / A; 334 float gamma2 = gamma * gamma; 335 // The bias is computed from gamma with (eq. 5), where the quantization 336 // multiplier Q can be factored out and thus the bias can be applied 337 // directly on the quantized coefficient. 338 biases[k] = 339 0.5 * (((1.0 + gamma2) / (1.0 - gamma2)) + 1.0 / std::log(gamma)); 340 } 341 } 342 343 constexpr std::array<int, SAVED_COEFS> Q_POS = {0, 1, 8, 16, 9, 344 2, 3, 10, 17, 24}; 345 346 bool is_nonzero_quantizers(const JQUANT_TBL* qtable) { 347 return std::all_of(Q_POS.begin(), Q_POS.end(), 348 [&](int pos) { return qtable->quantval[pos] != 0; }); 349 } 350 351 // Determine whether smoothing should be applied during decompression 352 bool do_smoothing(j_decompress_ptr cinfo) { 353 jpeg_decomp_master* m = cinfo->master; 354 bool smoothing_useful = false; 355 356 if (!cinfo->progressive_mode || cinfo->coef_bits == nullptr) { 357 return false; 358 } 359 auto* coef_bits_latch = m->coef_bits_latch; 360 auto* prev_coef_bits_latch = m->prev_coef_bits_latch; 361 362 for (int ci = 0; ci < cinfo->num_components; ci++) { 363 jpeg_component_info* compptr = &cinfo->comp_info[ci]; 364 JQUANT_TBL* qtable = compptr->quant_table; 365 int* coef_bits = cinfo->coef_bits[ci]; 366 int* prev_coef_bits = cinfo->coef_bits[ci + cinfo->num_components]; 367 368 // Return early if conditions for smoothing are not met 369 if (qtable == nullptr || !is_nonzero_quantizers(qtable) || 370 coef_bits[0] < 0) { 371 return false; 372 } 373 374 coef_bits_latch[ci][0] = coef_bits[0]; 375 376 for (int coefi = 1; coefi < SAVED_COEFS; coefi++) { 377 prev_coef_bits_latch[ci][coefi] = 378 cinfo->input_scan_number > 1 ? prev_coef_bits[coefi] : -1; 379 if (coef_bits[coefi] != 0) { 380 smoothing_useful = true; 381 } 382 coef_bits_latch[ci][coefi] = coef_bits[coefi]; 383 } 384 } 385 386 return smoothing_useful; 387 } 388 389 void PredictSmooth(j_decompress_ptr cinfo, JBLOCKARRAY blocks, int component, 390 size_t bx, int iy) { 391 const size_t imcu_row = cinfo->output_iMCU_row; 392 int16_t* scratch = cinfo->master->smoothing_scratch_; 393 std::vector<int> Q_VAL(SAVED_COEFS); 394 int* coef_bits; 395 396 std::array<std::array<int, 5>, 5> dc_values; 397 auto& compinfo = cinfo->comp_info[component]; 398 const size_t by0 = imcu_row * compinfo.v_samp_factor; 399 const size_t by = by0 + iy; 400 401 int prev_iy = by > 0 ? iy - 1 : 0; 402 int prev_prev_iy = by > 1 ? iy - 2 : prev_iy; 403 int next_iy = by + 1 < compinfo.height_in_blocks ? iy + 1 : iy; 404 int next_next_iy = by + 2 < compinfo.height_in_blocks ? iy + 2 : next_iy; 405 406 const int16_t* cur_row = blocks[iy][bx]; 407 const int16_t* prev_row = blocks[prev_iy][bx]; 408 const int16_t* prev_prev_row = blocks[prev_prev_iy][bx]; 409 const int16_t* next_row = blocks[next_iy][bx]; 410 const int16_t* next_next_row = blocks[next_next_iy][bx]; 411 412 int prev_block_ind = bx ? -DCTSIZE2 : 0; 413 int prev_prev_block_ind = bx > 1 ? -2 * DCTSIZE2 : prev_block_ind; 414 int next_block_ind = bx + 1 < compinfo.width_in_blocks ? DCTSIZE2 : 0; 415 int next_next_block_ind = 416 bx + 2 < compinfo.width_in_blocks ? DCTSIZE2 * 2 : next_block_ind; 417 418 std::array<const int16_t*, 5> row_ptrs = {prev_prev_row, prev_row, cur_row, 419 next_row, next_next_row}; 420 std::array<int, 5> block_inds = {prev_prev_block_ind, prev_block_ind, 0, 421 next_block_ind, next_next_block_ind}; 422 423 memcpy(scratch, cur_row, DCTSIZE2 * sizeof(cur_row[0])); 424 425 for (int r = 0; r < 5; ++r) { 426 for (int c = 0; c < 5; ++c) { 427 dc_values[r][c] = row_ptrs[r][block_inds[c]]; 428 } 429 } 430 // Get the correct coef_bits: In case of an incomplete scan, we use the 431 // prev coefficients. 432 if (cinfo->output_iMCU_row + 1 > cinfo->input_iMCU_row) { 433 coef_bits = cinfo->master->prev_coef_bits_latch[component]; 434 } else { 435 coef_bits = cinfo->master->coef_bits_latch[component]; 436 } 437 438 bool change_dc = true; 439 for (int i = 1; i < SAVED_COEFS; i++) { 440 if (coef_bits[i] != -1) { 441 change_dc = false; 442 break; 443 } 444 } 445 446 JQUANT_TBL* quanttbl = cinfo->quant_tbl_ptrs[compinfo.quant_tbl_no]; 447 for (size_t i = 0; i < 6; ++i) { 448 Q_VAL[i] = quanttbl->quantval[Q_POS[i]]; 449 } 450 if (change_dc) { 451 for (size_t i = 6; i < SAVED_COEFS; ++i) { 452 Q_VAL[i] = quanttbl->quantval[Q_POS[i]]; 453 } 454 } 455 auto calculate_dct_value = [&](int coef_index) { 456 int64_t num = 0; 457 int pred; 458 int Al; 459 // we use the symmetry of the smoothing matrices by transposing the 5x5 dc 460 // matrix in that case. 461 bool swap_indices = coef_index == 2 || coef_index == 5 || coef_index == 8 || 462 coef_index == 9; 463 auto dc = [&](int i, int j) { 464 return swap_indices ? dc_values[j][i] : dc_values[i][j]; 465 }; 466 JPEGLI_CHECK(coef_index >= 0 && coef_index < 10); 467 Al = coef_bits[coef_index]; 468 switch (coef_index) { 469 case 0: 470 // set the DC 471 num = (-2 * dc(0, 0) - 6 * dc(0, 1) - 8 * dc(0, 2) - 6 * dc(0, 3) - 472 2 * dc(0, 4) - 6 * dc(1, 0) + 6 * dc(1, 1) + 42 * dc(1, 2) + 473 6 * dc(1, 3) - 6 * dc(1, 4) - 8 * dc(2, 0) + 42 * dc(2, 1) + 474 152 * dc(2, 2) + 42 * dc(2, 3) - 8 * dc(2, 4) - 6 * dc(3, 0) + 475 6 * dc(3, 1) + 42 * dc(3, 2) + 6 * dc(3, 3) - 6 * dc(3, 4) - 476 2 * dc(4, 0) - 6 * dc(4, 1) - 8 * dc(4, 2) - 6 * dc(4, 3) - 477 2 * dc(4, 4)); 478 // special case: for the DC the dequantization is different 479 Al = 0; 480 break; 481 case 1: 482 case 2: 483 // set Q01 or Q10 484 num = (change_dc ? (-dc(0, 0) - dc(0, 1) + dc(0, 3) + dc(0, 4) - 485 3 * dc(1, 0) + 13 * dc(1, 1) - 13 * dc(1, 3) + 486 3 * dc(1, 4) - 3 * dc(2, 0) + 38 * dc(2, 1) - 487 38 * dc(2, 3) + 3 * dc(2, 4) - 3 * dc(3, 0) + 488 13 * dc(3, 1) - 13 * dc(3, 3) + 3 * dc(3, 4) - 489 dc(4, 0) - dc(4, 1) + dc(4, 3) + dc(4, 4)) 490 : (-7 * dc(2, 0) + 50 * dc(2, 1) - 50 * dc(2, 3) + 491 7 * dc(2, 4))); 492 break; 493 case 3: 494 case 5: 495 // set Q02 or Q20 496 num = (change_dc 497 ? dc(0, 2) + 2 * dc(1, 1) + 7 * dc(1, 2) + 2 * dc(1, 3) - 498 5 * dc(2, 1) - 14 * dc(2, 2) - 5 * dc(2, 3) + 499 2 * dc(3, 1) + 7 * dc(3, 2) + 2 * dc(3, 3) + dc(4, 2) 500 : (-dc(0, 2) + 13 * dc(1, 2) - 24 * dc(2, 2) + 501 13 * dc(3, 2) - dc(4, 2))); 502 break; 503 case 4: 504 // set Q11 505 num = 506 (change_dc ? -dc(0, 0) + dc(0, 4) + 9 * dc(1, 1) - 9 * dc(1, 3) - 507 9 * dc(3, 1) + 9 * dc(3, 3) + dc(4, 0) - dc(4, 4) 508 : (dc(1, 4) + dc(3, 0) - 10 * dc(3, 1) + 10 * dc(3, 3) - 509 dc(0, 1) - dc(3, 4) + dc(4, 1) - dc(4, 3) + dc(0, 3) - 510 dc(1, 0) + 10 * dc(1, 1) - 10 * dc(1, 3))); 511 break; 512 case 6: 513 case 9: 514 // set Q03 or Q30 515 num = (dc(1, 1) - dc(1, 3) + 2 * dc(2, 1) - 2 * dc(2, 3) + dc(3, 1) - 516 dc(3, 3)); 517 break; 518 case 7: 519 case 8: 520 default: 521 // set Q12 and Q21 522 num = (dc(1, 1) - 3 * dc(1, 2) + dc(1, 3) - dc(3, 1) + 3 * dc(3, 2) - 523 dc(3, 3)); 524 break; 525 } 526 num = Q_VAL[0] * num; 527 if (num >= 0) { 528 pred = ((Q_VAL[coef_index] << 7) + num) / (Q_VAL[coef_index] << 8); 529 if (Al > 0 && pred >= (1 << Al)) pred = (1 << Al) - 1; 530 } else { 531 pred = ((Q_VAL[coef_index] << 7) - num) / (Q_VAL[coef_index] << 8); 532 if (Al > 0 && pred >= (1 << Al)) pred = (1 << Al) - 1; 533 pred = -pred; 534 } 535 return static_cast<int16_t>(pred); 536 }; 537 538 int loop_end = change_dc ? SAVED_COEFS : 6; 539 for (int i = 1; i < loop_end; ++i) { 540 if (coef_bits[i] != 0 && scratch[Q_POS[i]] == 0) { 541 scratch[Q_POS[i]] = calculate_dct_value(i); 542 } 543 } 544 if (change_dc) { 545 scratch[0] = calculate_dct_value(0); 546 } 547 } 548 549 void PrepareForOutput(j_decompress_ptr cinfo) { 550 jpeg_decomp_master* m = cinfo->master; 551 bool smoothing = do_smoothing(cinfo); 552 m->apply_smoothing = smoothing && FROM_JXL_BOOL(cinfo->do_block_smoothing); 553 size_t coeffs_per_block = cinfo->num_components * DCTSIZE2; 554 memset(m->nonzeros_, 0, coeffs_per_block * sizeof(m->nonzeros_[0])); 555 memset(m->sumabs_, 0, coeffs_per_block * sizeof(m->sumabs_[0])); 556 memset(m->num_processed_blocks_, 0, sizeof(m->num_processed_blocks_)); 557 memset(m->biases_, 0, coeffs_per_block * sizeof(m->biases_[0])); 558 cinfo->output_iMCU_row = 0; 559 cinfo->output_scanline = 0; 560 const float kDequantScale = 1.0f / (8 * 255); 561 for (int c = 0; c < cinfo->num_components; c++) { 562 const auto& comp = cinfo->comp_info[c]; 563 JQUANT_TBL* table = comp.quant_table; 564 if (table == nullptr) continue; 565 for (size_t k = 0; k < DCTSIZE2; ++k) { 566 m->dequant_[c * DCTSIZE2 + k] = table->quantval[k] * kDequantScale; 567 } 568 } 569 JPEGLI_CHECK(ChooseInverseTransform(cinfo)); 570 ChooseColorTransform(cinfo); 571 } 572 573 void DecodeCurrentiMCURow(j_decompress_ptr cinfo) { 574 jpeg_decomp_master* m = cinfo->master; 575 const size_t imcu_row = cinfo->output_iMCU_row; 576 JBLOCKARRAY blocks[kMaxComponents]; 577 for (int c = 0; c < cinfo->num_components; ++c) { 578 const jpeg_component_info* comp = &cinfo->comp_info[c]; 579 int by0 = imcu_row * comp->v_samp_factor; 580 int block_rows_left = comp->height_in_blocks - by0; 581 int max_block_rows = std::min(comp->v_samp_factor, block_rows_left); 582 int offset = m->streaming_mode_ ? 0 : by0; 583 blocks[c] = (*cinfo->mem->access_virt_barray)( 584 reinterpret_cast<j_common_ptr>(cinfo), m->coef_arrays[c], offset, 585 max_block_rows, FALSE); 586 } 587 for (int c = 0; c < cinfo->num_components; ++c) { 588 size_t k0 = c * DCTSIZE2; 589 auto& compinfo = cinfo->comp_info[c]; 590 size_t block_row = imcu_row * compinfo.v_samp_factor; 591 if (ShouldApplyDequantBiases(cinfo, c)) { 592 // Update statistics for this iMCU row. 593 for (int iy = 0; iy < compinfo.v_samp_factor; ++iy) { 594 size_t by = block_row + iy; 595 if (by >= compinfo.height_in_blocks) { 596 continue; 597 } 598 int16_t* JXL_RESTRICT coeffs = &blocks[c][iy][0][0]; 599 size_t num = compinfo.width_in_blocks * DCTSIZE2; 600 GatherBlockStats(coeffs, num, &m->nonzeros_[k0], &m->sumabs_[k0]); 601 m->num_processed_blocks_[c] += compinfo.width_in_blocks; 602 } 603 if (imcu_row % 4 == 3) { 604 // Re-compute optimal biases every few iMCU-rows. 605 ComputeOptimalLaplacianBiases(m->num_processed_blocks_[c], 606 &m->nonzeros_[k0], &m->sumabs_[k0], 607 &m->biases_[k0]); 608 } 609 } 610 RowBuffer<float>* raw_out = &m->raw_output_[c]; 611 for (int iy = 0; iy < compinfo.v_samp_factor; ++iy) { 612 size_t by = block_row + iy; 613 if (by >= compinfo.height_in_blocks) { 614 continue; 615 } 616 size_t dctsize = m->scaled_dct_size[c]; 617 int16_t* JXL_RESTRICT row_in = &blocks[c][iy][0][0]; 618 float* JXL_RESTRICT row_out = raw_out->Row(by * dctsize); 619 for (size_t bx = 0; bx < compinfo.width_in_blocks; ++bx) { 620 if (m->apply_smoothing) { 621 PredictSmooth(cinfo, blocks[c], c, bx, iy); 622 (*m->inverse_transform[c])(m->smoothing_scratch_, &m->dequant_[k0], 623 &m->biases_[k0], m->idct_scratch_, 624 &row_out[bx * dctsize], raw_out->stride(), 625 dctsize); 626 } else { 627 (*m->inverse_transform[c])(&row_in[bx * DCTSIZE2], &m->dequant_[k0], 628 &m->biases_[k0], m->idct_scratch_, 629 &row_out[bx * dctsize], raw_out->stride(), 630 dctsize); 631 } 632 } 633 if (m->streaming_mode_) { 634 memset(row_in, 0, compinfo.width_in_blocks * sizeof(JBLOCK)); 635 } 636 } 637 } 638 } 639 640 void ProcessRawOutput(j_decompress_ptr cinfo, JSAMPIMAGE data) { 641 jpegli::DecodeCurrentiMCURow(cinfo); 642 jpeg_decomp_master* m = cinfo->master; 643 for (int c = 0; c < cinfo->num_components; ++c) { 644 const auto& compinfo = cinfo->comp_info[c]; 645 size_t comp_width = compinfo.width_in_blocks * DCTSIZE; 646 size_t comp_height = compinfo.height_in_blocks * DCTSIZE; 647 size_t comp_nrows = compinfo.v_samp_factor * DCTSIZE; 648 size_t y0 = cinfo->output_iMCU_row * compinfo.v_samp_factor * DCTSIZE; 649 size_t y1 = std::min(y0 + comp_nrows, comp_height); 650 for (size_t y = y0; y < y1; ++y) { 651 float* rows[1] = {m->raw_output_[c].Row(y)}; 652 uint8_t* output = data[c][y - y0]; 653 DecenterRow(rows[0], comp_width); 654 WriteToOutput(cinfo, rows, 0, comp_width, 1, output); 655 } 656 } 657 ++cinfo->output_iMCU_row; 658 cinfo->output_scanline += cinfo->max_v_samp_factor * DCTSIZE; 659 if (cinfo->output_scanline >= cinfo->output_height) { 660 ++m->output_passes_done_; 661 } 662 } 663 664 void ProcessOutput(j_decompress_ptr cinfo, size_t* num_output_rows, 665 JSAMPARRAY scanlines, size_t max_output_rows) { 666 jpeg_decomp_master* m = cinfo->master; 667 const int vfactor = cinfo->max_v_samp_factor; 668 const int hfactor = cinfo->max_h_samp_factor; 669 const size_t context = m->need_context_rows_ ? 1 : 0; 670 const size_t imcu_row = cinfo->output_iMCU_row; 671 const size_t imcu_height = vfactor * m->min_scaled_dct_size; 672 const size_t imcu_width = hfactor * m->min_scaled_dct_size; 673 const size_t output_width = m->iMCU_cols_ * imcu_width; 674 if (imcu_row == cinfo->total_iMCU_rows || 675 (imcu_row > context && 676 cinfo->output_scanline < (imcu_row - context) * imcu_height)) { 677 // We are ready to output some scanlines. 678 size_t ybegin = cinfo->output_scanline; 679 size_t yend = (imcu_row == cinfo->total_iMCU_rows 680 ? cinfo->output_height 681 : (imcu_row - context) * imcu_height); 682 yend = std::min<size_t>(yend, ybegin + max_output_rows - *num_output_rows); 683 size_t yb = (ybegin / vfactor) * vfactor; 684 size_t ye = DivCeil(yend, vfactor) * vfactor; 685 for (size_t y = yb; y < ye; y += vfactor) { 686 for (int c = 0; c < cinfo->num_components; ++c) { 687 RowBuffer<float>* raw_out = &m->raw_output_[c]; 688 RowBuffer<float>* render_out = &m->render_output_[c]; 689 int line_groups = vfactor / m->v_factor[c]; 690 int downsampled_width = output_width / m->h_factor[c]; 691 size_t yc = y / m->v_factor[c]; 692 for (int dy = 0; dy < line_groups; ++dy) { 693 size_t ymid = yc + dy; 694 const float* JXL_RESTRICT row_mid = raw_out->Row(ymid); 695 if (cinfo->do_fancy_upsampling && m->v_factor[c] == 2) { 696 const float* JXL_RESTRICT row_top = 697 ymid == 0 ? row_mid : raw_out->Row(ymid - 1); 698 const float* JXL_RESTRICT row_bot = ymid + 1 == m->raw_height_[c] 699 ? row_mid 700 : raw_out->Row(ymid + 1); 701 Upsample2Vertical(row_top, row_mid, row_bot, 702 render_out->Row(2 * dy), 703 render_out->Row(2 * dy + 1), downsampled_width); 704 } else { 705 for (int yix = 0; yix < m->v_factor[c]; ++yix) { 706 memcpy(render_out->Row(m->v_factor[c] * dy + yix), row_mid, 707 downsampled_width * sizeof(float)); 708 } 709 } 710 if (m->h_factor[c] > 1) { 711 for (int yix = 0; yix < m->v_factor[c]; ++yix) { 712 int row_ix = m->v_factor[c] * dy + yix; 713 float* JXL_RESTRICT row = render_out->Row(row_ix); 714 float* JXL_RESTRICT tmp = m->upsample_scratch_; 715 if (cinfo->do_fancy_upsampling && m->h_factor[c] == 2) { 716 Upsample2Horizontal(row, tmp, output_width); 717 } else { 718 // TODO(szabadka) SIMDify this. 719 for (size_t x = 0; x < output_width; ++x) { 720 tmp[x] = row[x / m->h_factor[c]]; 721 } 722 memcpy(row, tmp, output_width * sizeof(tmp[0])); 723 } 724 } 725 } 726 } 727 } 728 for (int yix = 0; yix < vfactor; ++yix) { 729 if (y + yix < ybegin || y + yix >= yend) continue; 730 float* rows[kMaxComponents]; 731 int num_all_components = 732 std::max(cinfo->out_color_components, cinfo->num_components); 733 for (int c = 0; c < num_all_components; ++c) { 734 rows[c] = m->render_output_[c].Row(yix); 735 } 736 (*m->color_transform)(rows, output_width); 737 for (int c = 0; c < cinfo->out_color_components; ++c) { 738 // Undo the centering of the sample values around zero. 739 DecenterRow(rows[c], output_width); 740 } 741 if (scanlines) { 742 uint8_t* output = scanlines[*num_output_rows]; 743 WriteToOutput(cinfo, rows, m->xoffset_, cinfo->output_width, 744 cinfo->out_color_components, output); 745 } 746 JPEGLI_CHECK(cinfo->output_scanline == y + yix); 747 ++cinfo->output_scanline; 748 ++(*num_output_rows); 749 if (cinfo->output_scanline == cinfo->output_height) { 750 ++m->output_passes_done_; 751 } 752 } 753 } 754 } else { 755 DecodeCurrentiMCURow(cinfo); 756 ++cinfo->output_iMCU_row; 757 } 758 } 759 760 } // namespace jpegli 761 #endif // HWY_ONCE