1 /****************************************************************************** 2 * 3 * Copyright (C) 2012 Ittiam Systems Pvt Ltd, Bangalore 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 /** 19 ******************************************************************************* 20 * @file 21 * ihevcd_parse_residual.c 22 * 23 * @brief 24 * Contains functions for parsing residual data at TU level 25 * 26 * @author 27 * Harish 28 * 29 * @par List of Functions: 30 * 31 * @remarks 32 * None 33 * 34 ******************************************************************************* 35 */ 36 /*****************************************************************************/ 37 /* File Includes */ 38 /*****************************************************************************/ 39 #include <stdio.h> 40 #include <stddef.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <assert.h> 44 45 #include "ihevc_typedefs.h" 46 #include "iv.h" 47 #include "ivd.h" 48 #include "ihevcd_cxa.h" 49 50 #include "ihevc_defs.h" 51 #include "ihevc_debug.h" 52 #include "ihevc_structs.h" 53 #include "ihevc_macros.h" 54 #include "ihevc_platform_macros.h" 55 56 #include "ihevc_common_tables.h" 57 #include "ihevc_error.h" 58 #include "ihevc_cabac_tables.h" 59 60 #include "ihevcd_trace.h" 61 #include "ihevcd_defs.h" 62 #include "ihevcd_function_selector.h" 63 #include "ihevcd_structs.h" 64 #include "ihevcd_error.h" 65 #include "ihevcd_nal.h" 66 #include "ihevcd_bitstream.h" 67 #include "ihevcd_utils.h" 68 #include "ihevcd_parse_residual.h" 69 #include "ihevcd_cabac.h" 70 71 /** 72 ***************************************************************************** 73 * @brief returns context increment for sig coeff based on csbf neigbour 74 * flags (bottom and right) and current coeff postion in 4x4 block 75 * See section 9.3.3.1.4 for details on this context increment 76 * 77 * input : neigbour csbf flags(bit0:rightcsbf, bit1:bottom csbf) 78 * coeff idx in raster order (0-15) 79 * 80 * output : context increment for sig coeff flag 81 * 82 ***************************************************************************** 83 */ 84 const UWORD8 gau1_ihevcd_sigcoeff_ctxtinc[3][4][16] = 85 { 86 87 { 88 /* nbr csbf = 0: sigCtx = (xP+yP == 0) ? 2 : (xP+yP < 3) ? 1: 0 */ 89 { 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 90 /* nbr csbf = 1: sigCtx = (yP == 0) ? 2 : (yP == 1) ? 1: 0 */ 91 { 2, 1, 2, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0 }, 92 /* nbr csbf = 2: sigCtx = (xP == 0) ? 2 : (xP == 1) ? 1: 0 */ 93 { 2, 2, 1, 2, 1, 0, 2, 1, 0, 0, 1, 0, 0, 0, 0, 0 }, 94 /* nbr csbf = 3: sigCtx = 2 */ 95 { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }, 96 }, 97 { 98 /* nbr csbf = 0: sigCtx = (xP+yP == 0) ? 2 : (xP+yP < 3) ? 1: 0 */ 99 { 2, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 }, 100 /* nbr csbf = 1: sigCtx = (yP == 0) ? 2 : (yP == 1) ? 1: 0 */ 101 { 2, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 }, 102 /* nbr csbf = 2: sigCtx = (xP == 0) ? 2 : (xP == 1) ? 1: 0 */ 103 { 2, 1, 0, 0, 2, 1, 0, 0, 2, 1, 0, 0, 2, 1, 0, 0 }, 104 /* nbr csbf = 3: sigCtx = 2 */ 105 { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }, 106 }, 107 { 108 /* nbr csbf = 0: sigCtx = (xP+yP == 0) ? 2 : (xP+yP < 3) ? 1: 0 */ 109 { 2, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 }, 110 /* nbr csbf = 1: sigCtx = (yP == 0) ? 2 : (yP == 1) ? 1: 0 */ 111 { 2, 1, 0, 0, 2, 1, 0, 0, 2, 1, 0, 0, 2, 1, 0, 0 }, 112 /* nbr csbf = 2: sigCtx = (xP == 0) ? 2 : (xP == 1) ? 1: 0 */ 113 { 2, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 }, 114 /* nbr csbf = 3: sigCtx = 2 */ 115 { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }, 116 }, 117 118 119 }; 120 121 122 123 /** 124 ***************************************************************************** 125 * @brief returns context increment for sig coeff for 4x4 tranform size as 126 * per Table 9-39 in section 9.3.3.1.4 127 * 128 * input : coeff idx in raster order (0-15) 129 * 130 * output : context increment for sig coeff flag 131 * 132 ***************************************************************************** 133 */ 134 const UWORD8 gau1_ihevcd_sigcoeff_ctxtinc_tr4[3][16] = 135 { 136 /* Upright diagonal scan */ 137 { 138 0, 2, 1, 6, 139 3, 4, 7, 6, 140 4, 5, 7, 8, 141 5, 8, 8, 8, 142 }, 143 /* Horizontal scan */ 144 { 145 0, 1, 4, 5, 146 2, 3, 4, 5, 147 6, 6, 8, 8, 148 7, 7, 8, 8, 149 }, 150 /* Vertical scan */ 151 { 152 0, 2, 6, 7, 153 1, 3, 6, 7, 154 4, 4, 8, 8, 155 5, 5, 8, 8, 156 }, 157 }; 158 159 160 /** 161 ******************************************************************************* 162 * 163 * @brief 164 * Parses Residual coding 165 * 166 * @par Description: 167 * Parses Residual coding as per Section:7.3.13 168 * 169 * @param[in] ps_codec 170 * Pointer to codec context 171 * 172 * @returns error code from IHEVCD_ERROR_T 173 * 174 * @remarks 175 * 176 * 177 ******************************************************************************* 178 */ 179 180 WORD32 ihevcd_parse_residual_coding(codec_t *ps_codec, 181 WORD32 x0, WORD32 y0, 182 WORD32 log2_trafo_size, 183 WORD32 c_idx, 184 WORD32 intra_pred_mode) 185 { 186 IHEVCD_ERROR_T ret = (IHEVCD_ERROR_T)IHEVCD_SUCCESS; 187 WORD32 transform_skip_flag; 188 WORD32 value; 189 pps_t *ps_pps; 190 WORD32 last_scan_pos, last_sub_blk; 191 bitstrm_t *ps_bitstrm = &ps_codec->s_parse.s_bitstrm; 192 WORD32 last_significant_coeff_x_prefix, last_significant_coeff_y_prefix; 193 WORD32 last_significant_coeff_x, last_significant_coeff_y; 194 const UWORD8 *pu1_scan_blk, *pu1_scan_coeff; 195 WORD32 scan_idx; 196 WORD32 i; 197 WORD32 sign_data_hiding_flag; 198 cab_ctxt_t *ps_cabac = &ps_codec->s_parse.s_cabac; 199 WORD32 gt1_ctxt = 1; 200 WORD32 c_max; 201 UWORD16 au2_csbf[9]; 202 tu_sblk_coeff_data_t *ps_tu_sblk_coeff_data; 203 WORD8 *pi1_num_coded_subblks; 204 WORD32 num_subblks; 205 WORD32 sig_coeff_base_ctxt, abs_gt1_base_ctxt; 206 UNUSED(x0); 207 UNUSED(y0); 208 ps_pps = ps_codec->s_parse.ps_pps; 209 210 sign_data_hiding_flag = ps_pps->i1_sign_data_hiding_flag; 211 transform_skip_flag = 0; 212 if(ps_pps->i1_transform_skip_enabled_flag && 213 !ps_codec->s_parse.s_cu.i4_cu_transquant_bypass && 214 (log2_trafo_size == 2)) 215 { 216 WORD32 ctxt_idx; 217 218 if(!c_idx) 219 { 220 ctxt_idx = IHEVC_CAB_TFM_SKIP0; 221 } 222 else 223 { 224 ctxt_idx = IHEVC_CAB_TFM_SKIP12; 225 } 226 TRACE_CABAC_CTXT("transform_skip_flag", ps_cabac->u4_range, ctxt_idx); 227 value = ihevcd_cabac_decode_bin(ps_cabac, 228 ps_bitstrm, 229 ctxt_idx); 230 AEV_TRACE("transform_skip_flag", value, ps_cabac->u4_range); 231 transform_skip_flag = value; 232 } 233 234 /* code the last_coeff_x_prefix as tunary binarized code */ 235 { 236 WORD32 ctxt_idx_x, ctxt_idx_y, ctx_shift; 237 WORD32 ctx_offset; 238 c_max = (log2_trafo_size << 1) - 1; 239 240 if(!c_idx) 241 { 242 ctx_offset = (3 * (log2_trafo_size - 2)) + ((log2_trafo_size - 1) >> 2); 243 ctxt_idx_x = IHEVC_CAB_COEFFX_PREFIX + ctx_offset; 244 ctxt_idx_y = IHEVC_CAB_COEFFY_PREFIX + ctx_offset; 245 ctx_shift = (log2_trafo_size + 1) >> 2; 246 } 247 else 248 { 249 ctxt_idx_x = IHEVC_CAB_COEFFX_PREFIX + 15; 250 ctxt_idx_y = IHEVC_CAB_COEFFY_PREFIX + 15; 251 ctx_shift = log2_trafo_size - 2; 252 } 253 254 TRACE_CABAC_CTXT("last_coeff_x_prefix", ps_cabac->u4_range, ctxt_idx_x); 255 last_significant_coeff_x_prefix = ihevcd_cabac_decode_bins_tunary(ps_cabac, 256 ps_bitstrm, 257 c_max, 258 ctxt_idx_x, 259 ctx_shift, 260 c_max); 261 262 AEV_TRACE("last_coeff_x_prefix", last_significant_coeff_x_prefix, ps_cabac->u4_range); 263 264 TRACE_CABAC_CTXT("last_coeff_y_prefix", ps_cabac->u4_range, ctxt_idx_y); 265 last_significant_coeff_y_prefix = ihevcd_cabac_decode_bins_tunary(ps_cabac, 266 ps_bitstrm, 267 c_max, 268 ctxt_idx_y, 269 ctx_shift, 270 c_max); 271 272 AEV_TRACE("last_coeff_y_prefix", last_significant_coeff_y_prefix, ps_cabac->u4_range); 273 274 275 last_significant_coeff_x = last_significant_coeff_x_prefix; 276 if(last_significant_coeff_x_prefix > 3) 277 { 278 WORD32 suf_length = ((last_significant_coeff_x_prefix - 2) >> 1); 279 280 value = ihevcd_cabac_decode_bypass_bins(ps_cabac, 281 ps_bitstrm, 282 suf_length); 283 284 AEV_TRACE("last_coeff_x_suffix", value, ps_cabac->u4_range); 285 286 287 last_significant_coeff_x = 288 (1 << ((last_significant_coeff_x_prefix >> 1) - 1)) * 289 (2 + (last_significant_coeff_x_prefix & 1)) + value; 290 } 291 292 293 last_significant_coeff_y = last_significant_coeff_y_prefix; 294 if(last_significant_coeff_y_prefix > 3) 295 { 296 WORD32 suf_length = ((last_significant_coeff_y_prefix - 2) >> 1); 297 value = ihevcd_cabac_decode_bypass_bins(ps_cabac, 298 ps_bitstrm, 299 suf_length); 300 301 AEV_TRACE("last_coeff_y_suffix", value, ps_cabac->u4_range); 302 last_significant_coeff_y = 303 (1 << ((last_significant_coeff_y_prefix >> 1) - 1)) * 304 (2 + (last_significant_coeff_y_prefix & 1)) + value; 305 } 306 307 } 308 309 /* Choose a scan matrix based on intra flag, intra pred mode, transform size 310 and luma/chroma */ 311 scan_idx = SCAN_DIAG_UPRIGHT; 312 if(PRED_MODE_INTRA == ps_codec->s_parse.s_cu.i4_pred_mode) 313 { 314 if((2 == log2_trafo_size) || ((3 == log2_trafo_size) && (0 == c_idx))) 315 { 316 if((6 <= intra_pred_mode) && 317 (14 >= intra_pred_mode)) 318 { 319 scan_idx = SCAN_VERT; 320 } 321 else if((22 <= intra_pred_mode) && 322 (30 >= intra_pred_mode)) 323 { 324 scan_idx = SCAN_HORZ; 325 } 326 } 327 } 328 329 /* In case the scan is vertical, then swap X and Y positions */ 330 if(SCAN_VERT == scan_idx) 331 { 332 SWAP(last_significant_coeff_x, last_significant_coeff_y); 333 } 334 335 { 336 WORD8 *pi1_scan_idx; 337 WORD8 *pi1_buf = (WORD8 *)ps_codec->s_parse.pv_tu_coeff_data; 338 339 /* First WORD8 gives number of coded subblocks */ 340 pi1_num_coded_subblks = pi1_buf++; 341 342 /* Set number of coded subblocks in the current TU to zero */ 343 /* This will be updated later */ 344 *pi1_num_coded_subblks = 0; 345 346 /* Second WORD8 gives (scan idx << 1) | trans_skip */ 347 pi1_scan_idx = pi1_buf++; 348 *pi1_scan_idx = (scan_idx << 1) | transform_skip_flag; 349 350 /* Store the incremented pointer in pv_tu_coeff_data */ 351 ps_codec->s_parse.pv_tu_coeff_data = pi1_buf; 352 353 } 354 /** 355 * Given last_significant_coeff_y and last_significant_coeff_x find last sub block 356 * This is done by ignoring lower two bits of last_significant_coeff_y and last_significant_coeff_x 357 * and using scan matrix for lookup 358 */ 359 360 /* If transform is 4x4, last_sub_blk is zero */ 361 last_sub_blk = 0; 362 363 /* If transform is larger than 4x4, then based on scan_idx and transform size, choose a scan table */ 364 365 if(log2_trafo_size > 2) 366 { 367 WORD32 scan_pos; 368 WORD32 scan_mat_size; 369 pu1_scan_blk = (UWORD8 *)gapv_ihevc_scan[scan_idx * 3 + (log2_trafo_size - 2 - 1)]; 370 371 372 /* Divide the current transform to 4x4 subblocks and count number of 4x4 in the first row */ 373 /* This will be size of scan matrix to be used for subblock scanning */ 374 scan_mat_size = 1 << (log2_trafo_size - 2); 375 scan_pos = ((last_significant_coeff_y >> 2) * scan_mat_size) + 376 (last_significant_coeff_x >> 2); 377 378 last_sub_blk = pu1_scan_blk[scan_pos]; 379 } 380 pu1_scan_coeff = &gau1_ihevc_scan4x4[scan_idx][0]; 381 382 { 383 WORD32 scan_pos; 384 385 scan_pos = ((last_significant_coeff_y & 3) << 2) + 386 (last_significant_coeff_x & 3); 387 388 last_scan_pos = pu1_scan_coeff[scan_pos]; 389 } 390 pu1_scan_blk = (UWORD8 *)gapv_ihevc_invscan[scan_idx * 3 + (log2_trafo_size - 2 - 1)]; 391 pu1_scan_coeff = &gau1_ihevc_invscan4x4[scan_idx][0]; 392 393 /* Set CSBF array to zero */ 394 { 395 UWORD32 *pu4_csbf; 396 pu4_csbf = (void *)au2_csbf; 397 *pu4_csbf++ = 0; 398 *pu4_csbf++ = 0; 399 *pu4_csbf++ = 0; 400 *pu4_csbf = 0; 401 /* To avoid a check for y pos, 9th WORD16 in the array is set to zero */ 402 au2_csbf[8] = 0; 403 } 404 405 /*************************************************************************/ 406 /* derive base context index for sig coeff as per section 9.3.3.1.4 */ 407 /* TODO; convert to look up based on luma/chroma, scan type and tfr size */ 408 /*************************************************************************/ 409 if(!c_idx) 410 { 411 sig_coeff_base_ctxt = IHEVC_CAB_COEFF_FLAG; 412 abs_gt1_base_ctxt = IHEVC_CAB_COEFABS_GRTR1_FLAG; 413 414 if(3 == log2_trafo_size) 415 { 416 /* 8x8 transform size */ 417 sig_coeff_base_ctxt += (scan_idx == SCAN_DIAG_UPRIGHT) ? 9 : 15; 418 } 419 else if(3 < log2_trafo_size) 420 { 421 /* larger transform sizes */ 422 sig_coeff_base_ctxt += 21; 423 } 424 } 425 else 426 { 427 /* chroma context initializations */ 428 sig_coeff_base_ctxt = IHEVC_CAB_COEFF_FLAG + 27; 429 abs_gt1_base_ctxt = IHEVC_CAB_COEFABS_GRTR1_FLAG + 16; 430 431 if(3 == log2_trafo_size) 432 { 433 /* 8x8 transform size */ 434 sig_coeff_base_ctxt += 9; 435 } 436 else if(3 < log2_trafo_size) 437 { 438 /* larger transform sizes */ 439 sig_coeff_base_ctxt += 12; 440 } 441 } 442 num_subblks = 0; 443 /* Parse each 4x4 subblocks */ 444 for(i = last_sub_blk; i >= 0; i--) 445 { 446 WORD32 sub_blk_pos; 447 WORD32 infer_sig_coeff_flag; 448 WORD32 cur_csbf; 449 450 WORD32 n; 451 WORD32 num_coeff; 452 /* Sig coeff map for 16 entries in raster scan order. Upper 16 bits are used. 453 * MSB gives sig coeff flag for 0th coeff and so on 454 * UWORD16 would have been enough but kept as UWORD32 for code optimizations 455 * In arm unnecessary masking operations are saved 456 */ 457 UWORD32 u4_sig_coeff_map_raster; 458 WORD32 sign_hidden; 459 460 /* Sig coeff map in scan order */ 461 UWORD32 u4_sig_coeff_map; 462 WORD32 coeff_abs_level_greater2_flag; 463 UWORD32 u4_coeff_abs_level_greater1_map; 464 UWORD32 u4_coeff_abs_level_greater2_map; 465 UWORD32 u4_coeff_sign_map; 466 WORD32 first_sig_scan_pos, last_sig_scan_pos, num_greater1_flag, first_greater1_scan_pos; 467 WORD32 num_sig_coeff, sum_abs_level; 468 WORD32 nbr_csbf; 469 470 471 WORD32 ctxt_set; 472 WORD32 rice_param; 473 WORD32 xs, ys; 474 475 476 sub_blk_pos = 0; 477 if(i && (log2_trafo_size > 2)) 478 sub_blk_pos = pu1_scan_blk[i]; 479 480 /* Get xs and ys from scan position */ 481 /* This is needed for context modelling of significant coeff flag */ 482 xs = sub_blk_pos & ((1 << (log2_trafo_size - 2)) - 1); 483 ys = sub_blk_pos >> (log2_trafo_size - 2); 484 485 486 /* Check if neighbor subblocks are coded */ 487 { 488 489 nbr_csbf = 0; 490 491 /* Get Bottom sub blocks CSBF */ 492 nbr_csbf |= (au2_csbf[ys + 1] >> xs) & 1; 493 nbr_csbf <<= 1; 494 495 /* Get Right sub blocks CSBF */ 496 /* Even if xs is equal to (1 << (log2_trafo_size - 2 )) - 1, 497 since au2_csbf is set to zero at the beginning, csbf for 498 neighbor will be read as 0 */ 499 500 nbr_csbf |= (au2_csbf[ys] >> (xs + 1)) & 1; 501 502 503 } 504 cur_csbf = 0; 505 506 /* DC coeff is inferred, only if coded_sub_block is explicitly parsed as 1 */ 507 /* i.e. it is not inferred for first and last subblock */ 508 infer_sig_coeff_flag = 0; 509 if((i < last_sub_blk) && (i > 0)) 510 { 511 WORD32 ctxt_idx = IHEVC_CAB_CODED_SUBLK_IDX; 512 513 /* ctxt based on right / bottom avail csbf, section 9.3.3.1.3 */ 514 ctxt_idx += (nbr_csbf) ? 1 : 0; 515 516 /* Ctxt based on luma or chroma */ 517 ctxt_idx += c_idx ? 2 : 0; 518 TRACE_CABAC_CTXT("coded_sub_block_flag", ps_cabac->u4_range, ctxt_idx); 519 IHEVCD_CABAC_DECODE_BIN(cur_csbf, ps_cabac, ps_bitstrm, ctxt_idx); 520 AEV_TRACE("coded_sub_block_flag", cur_csbf, ps_cabac->u4_range); 521 522 infer_sig_coeff_flag = 1; 523 } 524 else /* if((i == last_sub_blk) || (sub_blk_pos == 0)) */ 525 { 526 /* CSBF is set to 1 for first and last subblock */ 527 /* Note for these subblocks sig_coeff_map is not inferred but instead parsed */ 528 cur_csbf = 1; 529 } 530 531 /* Set current sub blocks CSBF */ 532 { 533 UWORD32 u4_mask = 1 << xs; 534 if(cur_csbf) 535 au2_csbf[ys] |= u4_mask; 536 else 537 au2_csbf[ys] &= ~u4_mask; 538 539 } 540 541 /* If current subblock is not coded, proceed to the next subblock */ 542 if(0 == cur_csbf) 543 continue; 544 545 n = 15; 546 u4_sig_coeff_map_raster = 0; 547 u4_sig_coeff_map = 0; 548 num_coeff = 0; 549 if(i == last_sub_blk) 550 { 551 WORD32 pos = ((last_significant_coeff_y & 3) << 2) + 552 (last_significant_coeff_x & 3); 553 n = (last_scan_pos - 1); 554 /* Set Significant coeff map for last significant coeff flag as 1 */ 555 u4_sig_coeff_map_raster = 1 << pos; 556 u4_sig_coeff_map = 1 << last_scan_pos; 557 num_coeff = 1; 558 } 559 560 for(; n >= 0; n--) 561 { 562 WORD32 significant_coeff_flag; 563 564 if((n > 0 || !infer_sig_coeff_flag)) 565 { 566 //WORD32 coeff_pos; 567 WORD32 sig_ctxinc; 568 WORD32 ctxt_idx; 569 570 /* Coefficient position is needed for deriving context index for significant_coeff_flag */ 571 //coeff_pos = pu1_scan_coeff[n]; 572 /* derive the context inc as per section 9.3.3.1.4 */ 573 sig_ctxinc = 0; 574 if(2 == log2_trafo_size) 575 { 576 577 /* 4x4 transform size increment uses lookup */ 578 sig_ctxinc = gau1_ihevcd_sigcoeff_ctxtinc_tr4[scan_idx][n]; 579 } 580 else if(n || i) 581 { 582 /* ctxt for AC coeff depends on curpos and neigbour csbf */ 583 sig_ctxinc = gau1_ihevcd_sigcoeff_ctxtinc[scan_idx][nbr_csbf][n]; 584 585 /* based on luma subblock pos */ 586 sig_ctxinc += (i && (!c_idx)) ? 3 : 0; 587 588 } 589 else 590 { 591 /* DC coeff has fixed context for luma and chroma */ 592 sig_coeff_base_ctxt = (0 == c_idx) ? IHEVC_CAB_COEFF_FLAG : 593 (IHEVC_CAB_COEFF_FLAG + 27); 594 } 595 596 ctxt_idx = sig_ctxinc + sig_coeff_base_ctxt; 597 TRACE_CABAC_CTXT("significant_coeff_flag", ps_cabac->u4_range, ctxt_idx); 598 IHEVCD_CABAC_DECODE_BIN(significant_coeff_flag, ps_cabac, 599 ps_bitstrm, 600 ctxt_idx); 601 AEV_TRACE("significant_coeff_flag", significant_coeff_flag, ps_cabac->u4_range); 602 603 604 /* If at least one non-zero coeff is signalled then do not infer sig coeff map */ 605 /* for (0,0) coeff in the current sub block */ 606 if(significant_coeff_flag) 607 infer_sig_coeff_flag = 0; 608 609 // u4_sig_coeff_map_raster |= significant_coeff_flag 610 // << coeff_pos; 611 u4_sig_coeff_map |= significant_coeff_flag << n; 612 num_coeff += significant_coeff_flag; 613 } 614 615 616 } 617 /*********************************************************************/ 618 /* If infer_sig_coeff_flag is 1 then treat the 0th coeff as non zero */ 619 /* If infer_sig_coeff_flag is zero, then last significant_coeff_flag */ 620 /* is parsed in the above loop */ 621 /*********************************************************************/ 622 if(infer_sig_coeff_flag) 623 { 624 u4_sig_coeff_map_raster |= 1; 625 u4_sig_coeff_map |= 1; 626 num_coeff++; 627 } 628 629 /*********************************************************************/ 630 /* First subblock does not get an explicit csbf. It is assumed to */ 631 /* be 1. For this subblock there is chance of getting all */ 632 /* sig_coeff_flags to be zero. In such a case proceed to the next */ 633 /* subblock(which is end of parsing for the current transform block) */ 634 /*********************************************************************/ 635 636 if(0 == num_coeff) 637 continue; 638 639 /* Increment number of coded subblocks for the current TU */ 640 num_subblks++; 641 642 /* Set sig coeff map and subblock position */ 643 ps_tu_sblk_coeff_data = (tu_sblk_coeff_data_t *)ps_codec->s_parse.pv_tu_coeff_data; 644 ps_tu_sblk_coeff_data->u2_sig_coeff_map = u4_sig_coeff_map; 645 ps_tu_sblk_coeff_data->u2_subblk_pos = (ys << 8) | xs; 646 647 first_sig_scan_pos = 16; 648 last_sig_scan_pos = -1; 649 num_greater1_flag = 0; 650 first_greater1_scan_pos = -1; 651 u4_coeff_abs_level_greater1_map = 0; 652 653 654 /* context set based on luma subblock pos */ 655 ctxt_set = (i && (!c_idx)) ? 2 : 0; 656 657 /* See section 9.3.3.1.5 */ 658 ctxt_set += (0 == gt1_ctxt) ? 1 : 0; 659 660 gt1_ctxt = 1; 661 /* Instead of initializing n to 15, set it to 31-CLZ(sig coeff map) */ 662 { 663 UWORD32 u4_sig_coeff_map_shift; 664 UWORD32 clz; 665 clz = CLZ(u4_sig_coeff_map); 666 n = 31 - clz; 667 u4_sig_coeff_map_shift = u4_sig_coeff_map << clz; 668 /* For loop for n changed to do while to break early if sig_coeff_map_shift becomes zero */ 669 do 670 { 671 //WORD32 coeff_pos; 672 WORD32 ctxt_idx; 673 674 //TODO: Scan lookup will be removed later and instead u4_sig_coeff_map will be used 675 //coeff_pos = pu1_scan_coeff[n]; 676 677 if((u4_sig_coeff_map_shift >> 31) & 1) 678 { 679 680 /* abs_level_greater1_flag is sent for only first 8 non-zero levels in a subblock */ 681 if(num_greater1_flag < 8) 682 { 683 WORD32 coeff_abs_level_greater1_flag; 684 685 ctxt_idx = (ctxt_set * 4) + abs_gt1_base_ctxt + gt1_ctxt; 686 687 TRACE_CABAC_CTXT("coeff_abs_level_greater1_flag", ps_cabac->u4_range, ctxt_idx); 688 IHEVCD_CABAC_DECODE_BIN(coeff_abs_level_greater1_flag, ps_cabac, ps_bitstrm, ctxt_idx); 689 AEV_TRACE("coeff_abs_level_greater1_flag", coeff_abs_level_greater1_flag, ps_cabac->u4_range); 690 691 u4_coeff_abs_level_greater1_map |= coeff_abs_level_greater1_flag << n; 692 num_greater1_flag++; 693 694 /* first_greater1_scan_pos is obtained using CLZ on u4_coeff_abs_level_greater1_map*/ 695 /* outside the loop instead of the following check inside the loop */ 696 /* if( coeff_abs_level_greater1_flag && first_greater1_scan_pos == -1) */ 697 /* first_greater1_scan_pos = n; */ 698 699 if(coeff_abs_level_greater1_flag) 700 { 701 gt1_ctxt = 0; 702 } 703 else if(gt1_ctxt && (gt1_ctxt < 3)) 704 { 705 gt1_ctxt++; 706 } 707 708 } 709 else 710 break; 711 712 /* instead of computing last and first significan scan position using checks below */ 713 /* They are computed outside the loop using CLZ and CTZ on sig_coeff_map */ 714 /* if(last_sig_scan_pos == -1) */ 715 /* last_sig_scan_pos = n; */ 716 /* first_sig_scan_pos = n; */ 717 } 718 u4_sig_coeff_map_shift <<= 1; 719 n--; 720 /* If there are zero coeffs, then shift by as many zero coeffs and decrement n */ 721 clz = CLZ(u4_sig_coeff_map_shift); 722 u4_sig_coeff_map_shift <<= clz; 723 n -= clz; 724 }while(u4_sig_coeff_map_shift); 725 } 726 /* At this level u4_sig_coeff_map is non-zero i.e. has atleast one non-zero coeff */ 727 last_sig_scan_pos = (31 - CLZ(u4_sig_coeff_map)); 728 first_sig_scan_pos = CTZ(u4_sig_coeff_map); 729 sign_hidden = (((last_sig_scan_pos - first_sig_scan_pos) > 3) && !ps_codec->s_parse.s_cu.i4_cu_transquant_bypass); 730 731 u4_coeff_abs_level_greater2_map = 0; 732 733 if(u4_coeff_abs_level_greater1_map) 734 { 735 /* Check if the first level > 1 is greater than 2 */ 736 WORD32 ctxt_idx; 737 first_greater1_scan_pos = (31 - CLZ(u4_coeff_abs_level_greater1_map)); 738 739 740 ctxt_idx = IHEVC_CAB_COEFABS_GRTR2_FLAG; 741 742 ctxt_idx += (!c_idx) ? ctxt_set : (ctxt_set + 4); 743 TRACE_CABAC_CTXT("coeff_abs_level_greater2_flag", ps_cabac->u4_range, ctxt_idx); 744 IHEVCD_CABAC_DECODE_BIN(coeff_abs_level_greater2_flag, ps_cabac, ps_bitstrm, ctxt_idx); 745 AEV_TRACE("coeff_abs_level_greater2_flag", coeff_abs_level_greater2_flag, ps_cabac->u4_range); 746 u4_coeff_abs_level_greater2_map = coeff_abs_level_greater2_flag << first_greater1_scan_pos; 747 } 748 749 750 u4_coeff_sign_map = 0; 751 752 /* Parse sign flags */ 753 if(!sign_data_hiding_flag || !sign_hidden) 754 { 755 IHEVCD_CABAC_DECODE_BYPASS_BINS(value, ps_cabac, ps_bitstrm, num_coeff); 756 AEV_TRACE("sign_flags", value, ps_cabac->u4_range); 757 u4_coeff_sign_map = value << (32 - num_coeff); 758 } 759 else 760 { 761 IHEVCD_CABAC_DECODE_BYPASS_BINS(value, ps_cabac, ps_bitstrm, (num_coeff - 1)); 762 AEV_TRACE("sign_flags", value, ps_cabac->u4_range); 763 u4_coeff_sign_map = value << (32 - (num_coeff - 1)); 764 } 765 766 num_sig_coeff = 0; 767 sum_abs_level = 0; 768 rice_param = 0; 769 { 770 UWORD32 clz; 771 UWORD32 u4_sig_coeff_map_shift; 772 clz = CLZ(u4_sig_coeff_map); 773 n = 31 - clz; 774 u4_sig_coeff_map_shift = u4_sig_coeff_map << clz; 775 /* For loop for n changed to do while to break early if sig_coeff_map_shift becomes zero */ 776 do 777 { 778 779 if((u4_sig_coeff_map_shift >> 31) & 1) 780 { 781 WORD32 base_lvl; 782 WORD32 coeff_abs_level_remaining; 783 WORD32 level; 784 base_lvl = 1; 785 786 /* Update base_lvl if it is greater than 1 */ 787 if((u4_coeff_abs_level_greater1_map >> n) & 1) 788 base_lvl++; 789 790 /* Update base_lvl if it is greater than 2 */ 791 if((u4_coeff_abs_level_greater2_map >> n) & 1) 792 base_lvl++; 793 794 /* If level is greater than 3/2/1 based on the greater1 and greater2 maps, 795 * decode remaining level (level - base_lvl) will be signalled as bypass bins 796 */ 797 coeff_abs_level_remaining = 0; 798 if(base_lvl == ((num_sig_coeff < 8) ? ((n == first_greater1_scan_pos) ? 3 : 2) : 1)) 799 { 800 UWORD32 u4_prefix; 801 WORD32 bin; 802 803 u4_prefix = 0; 804 805 do 806 { 807 IHEVCD_CABAC_DECODE_BYPASS_BIN(bin, ps_cabac, ps_bitstrm); 808 u4_prefix++; 809 810 if((WORD32)u4_prefix == 19 - rice_param) 811 { 812 bin = 1; 813 break; 814 } 815 816 }while(bin); 817 818 u4_prefix = u4_prefix - 1; 819 if(u4_prefix < 3) 820 { 821 UWORD32 u4_suffix; 822 823 coeff_abs_level_remaining = (u4_prefix << rice_param); 824 if(rice_param) 825 { 826 IHEVCD_CABAC_DECODE_BYPASS_BINS(u4_suffix, ps_cabac, ps_bitstrm, rice_param); 827 828 coeff_abs_level_remaining |= u4_suffix; 829 } 830 } 831 else 832 { 833 UWORD32 u4_suffix; 834 UWORD32 u4_numbins; 835 836 //u4_prefix = CLIP3(u4_prefix, 0, 19 - rice_param); 837 838 u4_numbins = (u4_prefix - 3 + rice_param); 839 coeff_abs_level_remaining = (((1 << (u4_prefix - 3)) + 3 - 1) << rice_param); 840 if(u4_numbins) 841 { 842 IHEVCD_CABAC_DECODE_BYPASS_BINS(u4_suffix, ps_cabac, ps_bitstrm, u4_numbins); 843 coeff_abs_level_remaining += u4_suffix; 844 } 845 } 846 847 848 AEV_TRACE("coeff_abs_level_remaining", coeff_abs_level_remaining, ps_cabac->u4_range); 849 base_lvl += coeff_abs_level_remaining; 850 851 } 852 853 /* update the rice param based on coeff level */ 854 if((base_lvl > (3 << rice_param)) && (rice_param < 4)) 855 { 856 rice_param++; 857 } 858 859 /* Compute absolute level */ 860 level = base_lvl; 861 862 /* Update level with the sign */ 863 if((u4_coeff_sign_map >> 31) & 1) 864 level = -level; 865 866 u4_coeff_sign_map <<= 1; 867 /* Update sign in case sign is hidden */ 868 if(sign_data_hiding_flag && sign_hidden) 869 { 870 sum_abs_level += base_lvl; 871 872 if(n == first_sig_scan_pos && ((sum_abs_level % 2) == 1)) 873 level = -level; 874 } 875 876 /* Store the resulting level in non-zero level array */ 877 ps_tu_sblk_coeff_data->ai2_level[num_sig_coeff++] = level; 878 //AEV_TRACE("level", level, 0); 879 } 880 u4_sig_coeff_map_shift <<= 1; 881 n--; 882 /* If there are zero coeffs, then shift by as many zero coeffs and decrement n */ 883 clz = CLZ(u4_sig_coeff_map_shift); 884 u4_sig_coeff_map_shift <<= clz; 885 n -= clz; 886 887 888 }while(u4_sig_coeff_map_shift); 889 } 890 891 /* Increment the pv_tu_sblk_coeff_data */ 892 { 893 UWORD8 *pu1_buf = (UWORD8 *)ps_codec->s_parse.pv_tu_coeff_data; 894 pu1_buf += sizeof(tu_sblk_coeff_data_t) - SUBBLK_COEFF_CNT * sizeof(WORD16); 895 pu1_buf += num_coeff * sizeof(WORD16); 896 ps_codec->s_parse.pv_tu_coeff_data = pu1_buf; 897 898 } 899 900 } 901 /* Set number of coded sub blocks in the current TU */ 902 *pi1_num_coded_subblks = num_subblks; 903 904 return ret; 905 } 906
