1 /****************************************************************************** 2 * 3 * Copyright (C) 2015 The Android Open Source Project 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 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore 19 */ 20 /*! 21 *************************************************************************** 22 * \file ih264d_cabac.c 23 * 24 * \brief 25 * This file contains Binary decoding routines. 26 * 27 * \date 28 * 04/02/2003 29 * 30 * \author NS 31 *************************************************************************** 32 */ 33 #include <string.h> 34 #include "ih264_typedefs.h" 35 #include "ih264_macros.h" 36 #include "ih264_platform_macros.h" 37 #include "ih264d_structs.h" 38 #include "ih264d_cabac.h" 39 #include "ih264d_bitstrm.h" 40 #include "ih264d_error_handler.h" 41 #include "ih264d_defs.h" 42 #include "ih264d_debug.h" 43 #include "ih264d_tables.h" 44 #include "ih264d_parse_cabac.h" 45 #include "ih264d_tables.h" 46 47 48 49 /*! 50 ************************************************************************** 51 * \if Function name : ih264d_init_cabac_dec_envirnoment \endif 52 * 53 * \brief 54 * This function initializes CABAC decoding envirnoment. This function 55 * implements 9.3.3.2.3.1 of ISO/IEC14496-10. 56 * 57 * \return 58 * None 59 * 60 ************************************************************************** 61 */ 62 WORD32 ih264d_init_cabac_dec_envirnoment(decoding_envirnoment_t * ps_cab_env, 63 dec_bit_stream_t *ps_bitstrm) 64 { 65 UWORD32 u4_code_int_val_ofst; 66 67 ps_cab_env->u4_code_int_range = (HALF - 2) << 23; 68 NEXTBITS(u4_code_int_val_ofst, ps_bitstrm->u4_ofst, ps_bitstrm->pu4_buffer, 69 32); 70 FLUSHBITS(ps_bitstrm->u4_ofst, 9) 71 72 if(ps_bitstrm->u4_ofst > ps_bitstrm->u4_max_ofst) 73 return ERROR_EOB_FLUSHBITS_T; 74 75 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 76 77 /*brief description of the design adopted for CABAC*/ 78 /*according to the standard the u4_code_int_range needs to be initialized 0x 1FE(10 bits) and 79 9 bits from the bit stream need to be read and into the u4_code_int_val_ofst.As and when the 80 u4_code_int_range becomes less than 10 bits we need to renormalize and read from the bitstream* 81 82 In the implemented design 83 initially 84 85 range_new = range <<23 86 valOffset_new = valOffset << 23 + 23 bits(read from the bit stream) 87 88 Thus we have read 23 more bits ahead of time. 89 90 It can be mathematical proved that even with the modified range and u4_ofst the operations 91 like comparison and subtraction needed for a bin decode are still valid(both in the regular case and the bypass case) 92 93 As bins are decoded..we consume the bits that we have already read into the valOffset.The clz of Range 94 gives us the number of bits we consumed of the 23 bits that we have read ahead of time. 95 96 when the number bits we have consumed exceeds 23 ,we renormalize..and we read from the bitstream again*/ 97 98 RESET_BIN_COUNTS(ps_cab_env) 99 100 return OK; 101 } 102 103 /*****************************************************************************/ 104 /* */ 105 /* Function Name : ih264d_init_cabac_contexts */ 106 /* */ 107 /* Description : This function initializes the cabac contexts */ 108 /* depending upon slice type and Init_Idc value. */ 109 /* Inputs : ps_dec, slice type */ 110 /* Globals : <Does it use any global variables?> */ 111 /* Outputs : */ 112 /* Returns : void */ 113 /* */ 114 /* Issues : none */ 115 /* */ 116 /* Revision History: */ 117 /* */ 118 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 119 /* 03 05 2005 100153) Draft */ 120 /* */ 121 /*****************************************************************************/ 122 123 void ih264d_init_cabac_contexts(UWORD8 u1_slice_type, dec_struct_t * ps_dec) 124 { 125 126 bin_ctxt_model_t *p_cabac_ctxt_table_t = ps_dec->p_cabac_ctxt_table_t; 127 UWORD8 u1_qp_y = ps_dec->ps_cur_slice->u1_slice_qp; 128 UWORD8 u1_cabac_init_Idc = 0; 129 130 if(I_SLICE != u1_slice_type) 131 { 132 u1_cabac_init_Idc = ps_dec->ps_cur_slice->u1_cabac_init_idc; 133 } 134 135 { 136 /* MAKING ps_dec->p_ctxt_inc_mb_map a scratch buffer */ 137 /* 0th entry of CtxtIncMbMap will be always be containing default values 138 for CABAC context representing MB not available */ 139 ctxt_inc_mb_info_t *p_DefCtxt = ps_dec->p_ctxt_inc_mb_map - 1; 140 UWORD8 *pu1_temp; 141 WORD8 i; 142 p_DefCtxt->u1_mb_type = CAB_SKIP; 143 144 p_DefCtxt->u1_cbp = 0x0f; 145 p_DefCtxt->u1_intra_chroma_pred_mode = 0; 146 147 p_DefCtxt->u1_yuv_dc_csbp = 0x7; 148 149 p_DefCtxt->u1_transform8x8_ctxt = 0; 150 151 pu1_temp = (UWORD8*)p_DefCtxt->i1_ref_idx; 152 for(i = 0; i < 4; i++, pu1_temp++) 153 (*pu1_temp) = 0; 154 pu1_temp = (UWORD8*)p_DefCtxt->u1_mv; 155 for(i = 0; i < 16; i++, pu1_temp++) 156 (*pu1_temp) = 0; 157 ps_dec->ps_def_ctxt_mb_info = p_DefCtxt; 158 } 159 160 if(u1_slice_type == I_SLICE) 161 { 162 u1_cabac_init_Idc = 3; 163 ps_dec->p_mb_type_t = p_cabac_ctxt_table_t + MB_TYPE_I_SLICE; 164 } 165 else if(u1_slice_type == P_SLICE) 166 { 167 ps_dec->p_mb_type_t = p_cabac_ctxt_table_t + MB_TYPE_P_SLICE; 168 ps_dec->p_mb_skip_flag_t = p_cabac_ctxt_table_t + MB_SKIP_FLAG_P_SLICE; 169 ps_dec->p_sub_mb_type_t = p_cabac_ctxt_table_t + SUB_MB_TYPE_P_SLICE; 170 } 171 else if(u1_slice_type == B_SLICE) 172 { 173 ps_dec->p_mb_type_t = p_cabac_ctxt_table_t + MB_TYPE_B_SLICE; 174 ps_dec->p_mb_skip_flag_t = p_cabac_ctxt_table_t + MB_SKIP_FLAG_B_SLICE; 175 ps_dec->p_sub_mb_type_t = p_cabac_ctxt_table_t + SUB_MB_TYPE_B_SLICE; 176 } 177 { 178 bin_ctxt_model_t *p_cabac_ctxt_table_t_tmp = p_cabac_ctxt_table_t; 179 if(ps_dec->ps_cur_slice->u1_field_pic_flag) 180 { 181 p_cabac_ctxt_table_t_tmp += SIGNIFICANT_COEFF_FLAG_FLD; 182 183 } 184 else 185 { 186 p_cabac_ctxt_table_t_tmp += SIGNIFICANT_COEFF_FLAG_FRAME; 187 } 188 { 189 bin_ctxt_model_t * * p_significant_coeff_flag_t = 190 ps_dec->p_significant_coeff_flag_t; 191 p_significant_coeff_flag_t[0] = p_cabac_ctxt_table_t_tmp 192 + SIG_COEFF_CTXT_CAT_0_OFFSET; 193 p_significant_coeff_flag_t[1] = p_cabac_ctxt_table_t_tmp 194 + SIG_COEFF_CTXT_CAT_1_OFFSET; 195 p_significant_coeff_flag_t[2] = p_cabac_ctxt_table_t_tmp 196 + SIG_COEFF_CTXT_CAT_2_OFFSET; 197 p_significant_coeff_flag_t[3] = p_cabac_ctxt_table_t_tmp 198 + SIG_COEFF_CTXT_CAT_3_OFFSET; 199 p_significant_coeff_flag_t[4] = p_cabac_ctxt_table_t_tmp 200 + SIG_COEFF_CTXT_CAT_4_OFFSET; 201 202 p_significant_coeff_flag_t[5] = p_cabac_ctxt_table_t_tmp 203 + SIG_COEFF_CTXT_CAT_5_OFFSET; 204 205 } 206 } 207 208 memcpy(p_cabac_ctxt_table_t, 209 gau1_ih264d_cabac_ctxt_init_table[u1_cabac_init_Idc][u1_qp_y], 210 NUM_CABAC_CTXTS * sizeof(bin_ctxt_model_t)); 211 } 212 /*! 213 ************************************************************************** 214 * \if Function name : ih264d_decode_bin \endif 215 * 216 * \brief 217 * This function implements decoding process of a decision as defined 218 * in 9.3.3.2.2. 219 * 220 * \return 221 * Returns symbol decoded. 222 * 223 * \note 224 * It is specified in 9.3.3.2.3.2 that, one of the input to this function 225 * is CtxIdx. CtxIdx is used to identify state and MPS of that context 226 * (Refer Fig 9.11 - Flowchart for encoding a decision). To suffice that 227 * here we pass a pointer bin_ctxt_model_t which contains these values. 228 * 229 ************************************************************************** 230 */ 231 232 UWORD32 ih264d_decode_bin(UWORD32 u4_ctx_inc, 233 bin_ctxt_model_t *ps_src_bin_ctxt, 234 dec_bit_stream_t *ps_bitstrm, 235 decoding_envirnoment_t *ps_cab_env) 236 237 { 238 239 UWORD32 u4_qnt_int_range, u4_code_int_range, u4_code_int_val_ofst, 240 u4_int_range_lps; 241 242 UWORD32 u4_symbol, u4_mps_state; 243 244 bin_ctxt_model_t *ps_bin_ctxt; 245 246 UWORD32 table_lookup; 247 const UWORD32 *pu4_table = (const UWORD32 *)ps_cab_env->cabac_table; 248 UWORD32 u4_clz; 249 250 ps_bin_ctxt = ps_src_bin_ctxt + u4_ctx_inc; 251 252 u4_code_int_range = ps_cab_env->u4_code_int_range; 253 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 254 255 u4_mps_state = (ps_bin_ctxt->u1_mps_state); 256 u4_clz = CLZ(u4_code_int_range); 257 258 u4_qnt_int_range = u4_code_int_range << u4_clz; 259 u4_qnt_int_range = (u4_qnt_int_range >> 29) & 0x3; 260 261 table_lookup = pu4_table[(u4_mps_state << 2) + u4_qnt_int_range]; 262 u4_int_range_lps = table_lookup & 0xff; 263 264 u4_int_range_lps = u4_int_range_lps << (23 - u4_clz); 265 u4_code_int_range = u4_code_int_range - u4_int_range_lps; 266 267 u4_symbol = ((u4_mps_state >> 6) & 0x1); 268 269 u4_mps_state = (table_lookup >> 8) & 0x7F; 270 271 CHECK_IF_LPS(u4_code_int_range, u4_code_int_val_ofst, u4_symbol, 272 u4_int_range_lps, u4_mps_state, table_lookup) 273 274 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_8) 275 { 276 UWORD32 *pu4_buffer, u4_offset; 277 278 pu4_buffer = ps_bitstrm->pu4_buffer; 279 u4_offset = ps_bitstrm->u4_ofst; 280 281 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 282 pu4_buffer) 283 284 ps_bitstrm->u4_ofst = u4_offset; 285 } 286 287 INC_BIN_COUNT(ps_cab_env) 288 289 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 290 ps_cab_env->u4_code_int_range = u4_code_int_range; 291 ps_bin_ctxt->u1_mps_state = u4_mps_state; 292 293 return (u4_symbol); 294 } 295 296 /*! 297 ************************************************************************** 298 * \if Function name : ih264d_decode_terminate \endif 299 * 300 * \brief 301 * This function implements decoding process of a termination as defined 302 * 9.3.3.2.2.3 of ISO/IEC14496-10. 303 * 304 * \return 305 * Returns symbol decoded. 306 * 307 * \note 308 * This routine is called while decoding "end_of_skice_flag" and of the 309 * bin indicating PCM mode in MBType. 310 * 311 ************************************************************************** 312 */ 313 UWORD8 ih264d_decode_terminate(decoding_envirnoment_t * ps_cab_env, 314 dec_bit_stream_t * ps_stream) 315 { 316 UWORD32 u4_symbol; 317 UWORD32 u4_code_int_val_ofst, u4_code_int_range; 318 UWORD32 u4_clz; 319 320 u4_code_int_range = ps_cab_env->u4_code_int_range; 321 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 322 323 u4_clz = CLZ(u4_code_int_range); 324 u4_code_int_range -= (2 << (23 - u4_clz)); 325 326 if(u4_code_int_val_ofst >= u4_code_int_range) 327 { 328 /* S=1 */ 329 u4_symbol = 1; 330 331 { 332 333 /*the u4_ofst needs to be updated before termination*/ 334 ps_stream->u4_ofst += u4_clz; 335 336 } 337 338 } 339 else 340 { 341 /* S=0 */ 342 u4_symbol = 0; 343 344 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_8) 345 { 346 UWORD32 *pu4_buffer, u4_offset; 347 348 pu4_buffer = ps_stream->pu4_buffer; 349 u4_offset = ps_stream->u4_ofst; 350 351 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 352 pu4_buffer) 353 ps_stream->u4_ofst = u4_offset; 354 } 355 } 356 357 ps_cab_env->u4_code_int_range = u4_code_int_range; 358 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 359 360 INC_BIN_COUNT(ps_cab_env) 361 362 return (u4_symbol); 363 } 364 365 /*****************************************************************************/ 366 /* */ 367 /* Function Name : ih264d_decode_bins_tunary */ 368 /* */ 369 /* Description : This function decodes bins in the case of TUNARY */ 370 /* binarization technique.valid_length is assumed equal to 3 */ 371 /* and u1_max_bins <= 4 in this functon. */ 372 /* Inputs : <What inputs does the function take?> */ 373 /* Globals : <Does it use any global variables?> */ 374 /* Processing : <Describe how the function operates - include algorithm */ 375 /* description> */ 376 /* Outputs : <What does the function produce?> */ 377 /* Returns : <What does the function return?> */ 378 /* */ 379 /* Issues : */ 380 /* */ 381 /* Revision History: */ 382 /* */ 383 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 384 /* 20 11 2008 SH Draft */ 385 /* */ 386 /*****************************************************************************/ 387 388 UWORD32 ih264d_decode_bins_tunary(UWORD8 u1_max_bins, 389 UWORD32 u4_ctx_inc, 390 bin_ctxt_model_t *ps_src_bin_ctxt, 391 dec_bit_stream_t *ps_bitstrm, 392 decoding_envirnoment_t *ps_cab_env) 393 394 { 395 UWORD32 u4_value; 396 UWORD32 u4_symbol; 397 UWORD8 u4_ctx_Inc; 398 bin_ctxt_model_t *ps_bin_ctxt; 399 UWORD32 u4_code_int_range, u4_code_int_val_ofst; 400 const UWORD32 *pu4_table = (const UWORD32 *)ps_cab_env->cabac_table; 401 402 u4_value = 0; 403 404 /*u1_max_bins has to be less than or equal to 4, u1_max_bins <= 4 for this function*/ 405 406 /*here the valid length is assumed to be equal to 3 ,so the calling function is expected 407 to duplicate CtxInc if valid lenth is 2 and cmaxbin is greater than2*/ 408 u4_code_int_range = ps_cab_env->u4_code_int_range; 409 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 410 411 do 412 { 413 u4_ctx_Inc = u4_ctx_inc & 0xF; 414 u4_ctx_inc = u4_ctx_inc >> 4; 415 416 ps_bin_ctxt = ps_src_bin_ctxt + u4_ctx_Inc; 417 418 DECODE_ONE_BIN_MACRO(ps_bin_ctxt, u4_code_int_range, u4_code_int_val_ofst, 419 pu4_table, ps_bitstrm, u4_symbol) 420 421 INC_BIN_COUNT(ps_cab_env);INC_DECISION_BINS(ps_cab_env); 422 423 u4_value++; 424 } 425 while((u4_value < u1_max_bins) & (u4_symbol)); 426 427 u4_value = u4_value - 1 + u4_symbol; 428 429 ps_cab_env->u4_code_int_range = u4_code_int_range; 430 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 431 432 return (u4_value); 433 434 } 435 436 /*****************************************************************************/ 437 /* */ 438 /* Function Name : ih264d_decode_bins */ 439 /* */ 440 /* Description : This function decodes bins in the case of MSB_FIRST_FLC */ 441 /* binarization technique.valid_length is always equal max_bins */ 442 /* for MSB_FIRST_FLC. assumes u1_max_bins <= 4 */ 443 /* Inputs : <What inputs does the function take?> */ 444 /* Globals : <Does it use any global variables?> */ 445 /* Processing : <Describe how the function operates - include algorithm */ 446 /* description> */ 447 /* Outputs : <What does the function produce?> */ 448 /* Returns : <What does the function return?> */ 449 /* */ 450 /* Issues : <List any issues or problems with this function> */ 451 /* */ 452 /* Revision History: */ 453 /* */ 454 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 455 /* 20 11 2008 SH Draft */ 456 /* */ 457 /*****************************************************************************/ 458 459 UWORD32 ih264d_decode_bins(UWORD8 u1_max_bins, 460 UWORD32 u4_ctx_inc, 461 bin_ctxt_model_t *ps_src_bin_ctxt, 462 dec_bit_stream_t *ps_bitstrm, 463 decoding_envirnoment_t *ps_cab_env) 464 465 { 466 UWORD32 u4_value; 467 UWORD32 u4_symbol, i; 468 UWORD32 u4_ctxt_inc; 469 bin_ctxt_model_t *ps_bin_ctxt; 470 UWORD32 u4_code_int_range, u4_code_int_val_ofst; 471 const UWORD32 *pu4_table = (const UWORD32 *)ps_cab_env->cabac_table; 472 473 i = 0; 474 475 u4_value = 0; 476 477 /*u1_max_bins has to be less than or equal to 4, u1_max_bins <= 4 for this fucntion*/ 478 u4_code_int_range = ps_cab_env->u4_code_int_range; 479 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 480 481 do 482 { 483 u4_ctxt_inc = u4_ctx_inc & 0xf; 484 u4_ctx_inc = u4_ctx_inc >> 4; 485 486 ps_bin_ctxt = ps_src_bin_ctxt + u4_ctxt_inc; 487 488 DECODE_ONE_BIN_MACRO(ps_bin_ctxt, u4_code_int_range, u4_code_int_val_ofst, 489 pu4_table, ps_bitstrm, u4_symbol) 490 491 INC_BIN_COUNT(ps_cab_env);INC_DECISION_BINS(ps_cab_env); 492 493 u4_value = (u4_value << 1) | (u4_symbol); 494 495 i++; 496 } 497 while(i < u1_max_bins); 498 499 ps_cab_env->u4_code_int_range = u4_code_int_range; 500 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 501 502 return (u4_value); 503 504 } 505 506 /*****************************************************************************/ 507 /* */ 508 /* Function Name : ih264d_decode_bins_unary */ 509 /* */ 510 /* Description : This function decodes bins in the case of UNARY */ 511 /* binarization technique.here the valid length is taken to 5*/ 512 /* and cmax is always greater than 9 */ 513 /* Inputs : <What inputs does the function take?> */ 514 /* Globals : <Does it use any global variables?> */ 515 /* Processing : <Describe how the function operates - include algorithm */ 516 /* description> */ 517 /* Outputs : <What does the function produce?> */ 518 /* Returns : <What does the function return?> */ 519 /* */ 520 /* Issues : <List any issues or problems with this function> */ 521 /* */ 522 /* Revision History: */ 523 /* */ 524 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 525 /* 20 11 2008 SH Draft */ 526 /* */ 527 /*****************************************************************************/ 528 UWORD32 ih264d_decode_bins_unary(UWORD8 u1_max_bins, 529 UWORD32 u4_ctx_inc, 530 bin_ctxt_model_t *ps_src_bin_ctxt, 531 dec_bit_stream_t *ps_bitstrm, 532 decoding_envirnoment_t *ps_cab_env) 533 { 534 UWORD32 u4_value; 535 UWORD32 u4_symbol; 536 bin_ctxt_model_t *ps_bin_ctxt; 537 UWORD32 u4_ctx_Inc; 538 UWORD32 u4_code_int_range, u4_code_int_val_ofst; 539 const UWORD32 *pu4_table = (const UWORD32 *)ps_cab_env->cabac_table; 540 541 /* in this function the valid length for u4_ctx_inc is always taken to be,so if the 542 the valid length is lessthan 5 the caller need to duplicate accordingly*/ 543 544 /*u1_max_bins is always greater or equal to 9 we have the check for u1_max_bins only after the 2 loop*/ 545 u4_value = 0; 546 u4_code_int_range = ps_cab_env->u4_code_int_range; 547 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 548 549 do 550 { 551 u4_ctx_Inc = u4_ctx_inc & 0xf; 552 u4_ctx_inc = u4_ctx_inc >> 4; 553 554 ps_bin_ctxt = ps_src_bin_ctxt + u4_ctx_Inc; 555 556 DECODE_ONE_BIN_MACRO(ps_bin_ctxt, u4_code_int_range, u4_code_int_val_ofst, 557 pu4_table, ps_bitstrm, u4_symbol) 558 559 INC_BIN_COUNT(ps_cab_env);INC_DECISION_BINS(ps_cab_env); 560 561 u4_value++; 562 563 } 564 while(u4_symbol && u4_value < 4); 565 566 if(u4_symbol && (u4_value < u1_max_bins)) 567 { 568 569 u4_ctx_Inc = u4_ctx_inc & 0xf; 570 571 ps_bin_ctxt = ps_src_bin_ctxt + u4_ctx_Inc; 572 573 do 574 { 575 576 DECODE_ONE_BIN_MACRO(ps_bin_ctxt, u4_code_int_range, u4_code_int_val_ofst, 577 pu4_table, ps_bitstrm, u4_symbol) 578 579 INC_BIN_COUNT(ps_cab_env);INC_DECISION_BINS(ps_cab_env); 580 581 u4_value++; 582 583 } 584 while(u4_symbol && (u4_value < u1_max_bins)); 585 586 } 587 588 ps_cab_env->u4_code_int_range = u4_code_int_range; 589 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 590 591 u4_value = u4_value - 1 + u4_symbol; 592 593 return (u4_value); 594 595 } 596 597 /*****************************************************************************/ 598 /* */ 599 /* Function Name : ih264d_decode_bypass_bins_unary */ 600 /* */ 601 /* Description : This function is used in the case of UNARY coding */ 602 /* */ 603 /* */ 604 /* Inputs : <What inputs does the function take?> */ 605 /* Globals : <Does it use any global variables?> */ 606 /* Processing : <Describe how the function operates - include algorithm */ 607 /* description> */ 608 /* Outputs : <What does the function produce?> */ 609 /* Returns : <What does the function return?> */ 610 /* */ 611 /* Issues : <List any issues or problems with this function> */ 612 /* */ 613 /* Revision History: */ 614 /* */ 615 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 616 /* 13 10 2005 Ittiam Draft */ 617 /* */ 618 /*****************************************************************************/ 619 620 UWORD32 ih264d_decode_bypass_bins_unary(decoding_envirnoment_t *ps_cab_env, 621 dec_bit_stream_t *ps_bitstrm) 622 { 623 UWORD32 u4_value; 624 UWORD32 u4_bin; 625 UWORD32 u4_code_int_val_ofst, u4_code_int_range; 626 627 UWORD32 u1_max_bins; 628 629 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 630 u4_code_int_range = ps_cab_env->u4_code_int_range; 631 632 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_9) 633 { 634 UWORD32 *pu4_buffer, u4_offset; 635 636 pu4_buffer = ps_bitstrm->pu4_buffer; 637 u4_offset = ps_bitstrm->u4_ofst; 638 639 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 640 pu4_buffer) 641 ps_bitstrm->u4_ofst = u4_offset; 642 } 643 644 /*as it is called only form mvd*/ 645 u1_max_bins = 32; 646 u4_value = 0; 647 648 do 649 { 650 u4_value++; 651 652 u4_code_int_range = u4_code_int_range >> 1; 653 if(u4_code_int_val_ofst >= u4_code_int_range) 654 { 655 /* S=1 */ 656 u4_bin = 1; 657 u4_code_int_val_ofst -= u4_code_int_range; 658 } 659 else 660 { 661 /* S=0 */ 662 u4_bin = 0; 663 } 664 665 INC_BIN_COUNT(ps_cab_env);INC_BYPASS_BINS(ps_cab_env); 666 667 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_9) 668 { 669 UWORD32 *pu4_buffer, u4_offset; 670 671 pu4_buffer = ps_bitstrm->pu4_buffer; 672 u4_offset = ps_bitstrm->u4_ofst; 673 674 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 675 pu4_buffer) 676 677 ps_bitstrm->u4_ofst = u4_offset; 678 } 679 680 } 681 while(u4_bin && (u4_value < u1_max_bins)); 682 683 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 684 ps_cab_env->u4_code_int_range = u4_code_int_range; 685 u4_value = (u4_value - 1 + u4_bin); 686 687 return (u4_value); 688 } 689 690 /*****************************************************************************/ 691 /* */ 692 /* Function Name : ih264d_decode_bypass_bins */ 693 /* */ 694 /* Description : This function is used in the case of FLC coding */ 695 /* */ 696 /* */ 697 /* Inputs : <What inputs does the function take?> */ 698 /* Globals : <Does it use any global variables?> */ 699 /* Processing : <Describe how the function operates - include algorithm */ 700 /* description> */ 701 /* Outputs : <What does the function produce?> */ 702 /* Returns : <What does the function return?> */ 703 /* */ 704 /* Issues : <List any issues or problems with this function> */ 705 /* */ 706 /* Revision History: */ 707 /* */ 708 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 709 /* 13 10 2005 Ittiam Draft */ 710 /* */ 711 /*****************************************************************************/ 712 713 UWORD32 ih264d_decode_bypass_bins(decoding_envirnoment_t *ps_cab_env, 714 UWORD8 u1_max_bins, 715 dec_bit_stream_t *ps_bitstrm) 716 { 717 UWORD32 u4_bins; 718 UWORD32 u4_bin; 719 UWORD32 u4_code_int_val_ofst, u4_code_int_range; 720 721 u4_bins = 0; 722 u4_code_int_val_ofst = ps_cab_env->u4_code_int_val_ofst; 723 u4_code_int_range = ps_cab_env->u4_code_int_range; 724 725 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_9) 726 { 727 UWORD32 *pu4_buffer, u4_offset; 728 729 pu4_buffer = ps_bitstrm->pu4_buffer; 730 u4_offset = ps_bitstrm->u4_ofst; 731 732 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 733 pu4_buffer) 734 ps_bitstrm->u4_ofst = u4_offset; 735 } 736 737 do 738 { 739 740 u4_code_int_range = u4_code_int_range >> 1; 741 742 if(u4_code_int_val_ofst >= u4_code_int_range) 743 { 744 /* S=1 */ 745 u4_bin = 1; 746 u4_code_int_val_ofst -= u4_code_int_range; 747 } 748 else 749 { 750 /* S=0 */ 751 u4_bin = 0; 752 } 753 754 INC_BIN_COUNT(ps_cab_env);INC_BYPASS_BINS(ps_cab_env); 755 756 u4_bins = ((u4_bins << 1) | u4_bin); 757 u1_max_bins--; 758 759 if(u4_code_int_range < ONE_RIGHT_SHIFTED_BY_9) 760 { 761 UWORD32 *pu4_buffer, u4_offset; 762 763 pu4_buffer = ps_bitstrm->pu4_buffer; 764 u4_offset = ps_bitstrm->u4_ofst; 765 766 RENORM_RANGE_OFFSET(u4_code_int_range, u4_code_int_val_ofst, u4_offset, 767 pu4_buffer) 768 ps_bitstrm->u4_ofst = u4_offset; 769 } 770 771 } 772 while(u1_max_bins); 773 774 ps_cab_env->u4_code_int_val_ofst = u4_code_int_val_ofst; 775 ps_cab_env->u4_code_int_range = u4_code_int_range; 776 777 return (u4_bins); 778 } 779 780
