source/common/contexts.h

   1 /*****************************************************************************
   2 * Copyright (C) 2014 x265 project
   3 *
   4 * Authors: Steve Borho <steve@borho.org>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
  19 *
  20 * This program is also available under a commercial proprietary license.
  21 * For more information, contact us at license @ x265.com.
  22 *****************************************************************************/
  23
  24 #ifndef X265_CONTEXTS_H
  25 #define X265_CONTEXTS_H
  26
  27 #include "common.h"
  28
  29 #define NUM_SPLIT_FLAG_CTX          3   // number of context models for split flag
  30 #define NUM_SKIP_FLAG_CTX           3   // number of context models for skip flag
  31
  32 #define NUM_MERGE_FLAG_EXT_CTX      1   // number of context models for merge flag of merge extended
  33 #define NUM_MERGE_IDX_EXT_CTX       1   // number of context models for merge index of merge extended
  34
  35 #define NUM_PART_SIZE_CTX           4   // number of context models for partition size
  36 #define NUM_PRED_MODE_CTX           1   // number of context models for prediction mode
  37
  38 #define NUM_ADI_CTX                 1   // number of context models for intra prediction
  39
  40 #define NUM_CHROMA_PRED_CTX         2   // number of context models for intra prediction (chroma)
  41 #define NUM_INTER_DIR_CTX           5   // number of context models for inter prediction direction
  42 #define NUM_MV_RES_CTX              2   // number of context models for motion vector difference
  43
  44 #define NUM_REF_NO_CTX              2   // number of context models for reference index
  45 #define NUM_TRANS_SUBDIV_FLAG_CTX   3   // number of context models for transform subdivision flags
  46 #define NUM_QT_CBF_CTX              7   // number of context models for QT CBF
  47 #define NUM_QT_ROOT_CBF_CTX         1   // number of context models for QT ROOT CBF
  48 #define NUM_DELTA_QP_CTX            3   // number of context models for dQP
  49
  50 #define NUM_SIG_CG_FLAG_CTX         2   // number of context models for MULTI_LEVEL_SIGNIFICANCE
  51
  52 #define NUM_SIG_FLAG_CTX            42  // number of context models for sig flag
  53 #define NUM_SIG_FLAG_CTX_LUMA       27  // number of context models for luma sig flag
  54 #define NUM_SIG_FLAG_CTX_CHROMA     15  // number of context models for chroma sig flag
  55
  56 #define NUM_CTX_LAST_FLAG_XY        18  // number of context models for last coefficient position
  57 #define NUM_CTX_LAST_FLAG_XY_LUMA   15  // number of context models for last coefficient position of luma
  58 #define NUM_CTX_LAST_FLAG_XY_CHROMA 3   // number of context models for last coefficient position of chroma
  59
  60 #define NUM_ONE_FLAG_CTX            24  // number of context models for greater than 1 flag
  61 #define NUM_ONE_FLAG_CTX_LUMA       16  // number of context models for greater than 1 flag of luma
  62 #define NUM_ONE_FLAG_CTX_CHROMA     8   // number of context models for greater than 1 flag of chroma
  63 #define NUM_ABS_FLAG_CTX            6   // number of context models for greater than 2 flag
  64 #define NUM_ABS_FLAG_CTX_LUMA       4   // number of context models for greater than 2 flag of luma
  65 #define NUM_ABS_FLAG_CTX_CHROMA     2   // number of context models for greater than 2 flag of chroma
  66
  67 #define NUM_MVP_IDX_CTX             1   // number of context models for MVP index
  68
  69 #define NUM_SAO_MERGE_FLAG_CTX      1   // number of context models for SAO merge flags
  70 #define NUM_SAO_TYPE_IDX_CTX        1   // number of context models for SAO type index
  71
  72 #define NUM_TRANSFORMSKIP_FLAG_CTX  1   // number of context models for transform skipping
  73 #define NUM_TQUANT_BYPASS_FLAG_CTX  1
  74 #define CNU                         154 // dummy initialization value for unused context models 'Context model Not Used'
  75
  76 // Offset for context
  77 #define OFF_SPLIT_FLAG_CTX         (0)
  78 #define OFF_SKIP_FLAG_CTX          (OFF_SPLIT_FLAG_CTX         +     NUM_SPLIT_FLAG_CTX)
  79 #define OFF_MERGE_FLAG_EXT_CTX     (OFF_SKIP_FLAG_CTX          +     NUM_SKIP_FLAG_CTX)
  80 #define OFF_MERGE_IDX_EXT_CTX      (OFF_MERGE_FLAG_EXT_CTX     +     NUM_MERGE_FLAG_EXT_CTX)
  81 #define OFF_PART_SIZE_CTX          (OFF_MERGE_IDX_EXT_CTX      +     NUM_MERGE_IDX_EXT_CTX)
  82 #define OFF_PRED_MODE_CTX          (OFF_PART_SIZE_CTX          +     NUM_PART_SIZE_CTX)
  83 #define OFF_ADI_CTX                (OFF_PRED_MODE_CTX          +     NUM_PRED_MODE_CTX)
  84 #define OFF_CHROMA_PRED_CTX        (OFF_ADI_CTX                +     NUM_ADI_CTX)
  85 #define OFF_DELTA_QP_CTX           (OFF_CHROMA_PRED_CTX        +     NUM_CHROMA_PRED_CTX)
  86 #define OFF_INTER_DIR_CTX          (OFF_DELTA_QP_CTX           +     NUM_DELTA_QP_CTX)
  87 #define OFF_REF_NO_CTX             (OFF_INTER_DIR_CTX          +     NUM_INTER_DIR_CTX)
  88 #define OFF_MV_RES_CTX             (OFF_REF_NO_CTX             +     NUM_REF_NO_CTX)
  89 #define OFF_QT_CBF_CTX             (OFF_MV_RES_CTX             +     NUM_MV_RES_CTX)
  90 #define OFF_TRANS_SUBDIV_FLAG_CTX  (OFF_QT_CBF_CTX             +     NUM_QT_CBF_CTX)
  91 #define OFF_QT_ROOT_CBF_CTX        (OFF_TRANS_SUBDIV_FLAG_CTX  +     NUM_TRANS_SUBDIV_FLAG_CTX)
  92 #define OFF_SIG_CG_FLAG_CTX        (OFF_QT_ROOT_CBF_CTX        +     NUM_QT_ROOT_CBF_CTX)
  93 #define OFF_SIG_FLAG_CTX           (OFF_SIG_CG_FLAG_CTX        + 2 * NUM_SIG_CG_FLAG_CTX)
  94 #define OFF_CTX_LAST_FLAG_X        (OFF_SIG_FLAG_CTX           +     NUM_SIG_FLAG_CTX)
  95 #define OFF_CTX_LAST_FLAG_Y        (OFF_CTX_LAST_FLAG_X        +     NUM_CTX_LAST_FLAG_XY)
  96 #define OFF_ONE_FLAG_CTX           (OFF_CTX_LAST_FLAG_Y        +     NUM_CTX_LAST_FLAG_XY)
  97 #define OFF_ABS_FLAG_CTX           (OFF_ONE_FLAG_CTX           +     NUM_ONE_FLAG_CTX)
  98 #define OFF_MVP_IDX_CTX            (OFF_ABS_FLAG_CTX           +     NUM_ABS_FLAG_CTX)
  99 #define OFF_SAO_MERGE_FLAG_CTX     (OFF_MVP_IDX_CTX            +     NUM_MVP_IDX_CTX)
 100 #define OFF_SAO_TYPE_IDX_CTX       (OFF_SAO_MERGE_FLAG_CTX     +     NUM_SAO_MERGE_FLAG_CTX)
 101 #define OFF_TRANSFORMSKIP_FLAG_CTX (OFF_SAO_TYPE_IDX_CTX       +     NUM_SAO_TYPE_IDX_CTX)
 102 #define OFF_TQUANT_BYPASS_FLAG_CTX (OFF_TRANSFORMSKIP_FLAG_CTX + 2 * NUM_TRANSFORMSKIP_FLAG_CTX)
 103 #define MAX_OFF_CTX_MOD            (OFF_TQUANT_BYPASS_FLAG_CTX +     NUM_TQUANT_BYPASS_FLAG_CTX)
 104
 105 namespace x265 {
 106 // private namespace
 107
 108 extern const uint32_t g_entropyBits[128];
 109 extern const uint8_t g_nextState[128][2];
 110
 111 #define sbacGetMps(S)            ((S) & 1)
 112 #define sbacGetState(S)          ((S) >> 1)
 113 #define sbacNext(S, V)           (g_nextState[(S)][(V)])
 114 #define sbacGetEntropyBits(S, V) (g_entropyBits[(S) ^ (V)])
 115 #define sbacGetEntropyBitsTrm(V) (g_entropyBits[126 ^ (V)])
 116
 117 #define MAX_NUM_CHANNEL_TYPE     2
 118
 119 static const uint32_t ctxCbf[3][5] = { { 1, 0, 0, 0, 0 }, { 2, 3, 4, 5, 6 }, { 2, 3, 4, 5, 6 } };
 120 static const uint32_t significanceMapContextSetStart[MAX_NUM_CHANNEL_TYPE][3] = { { 0,  9, 21 }, { 0,  9, 12 } };
 121 static const uint32_t significanceMapContextSetSize[MAX_NUM_CHANNEL_TYPE][3]  = { { 9, 12,  6 }, { 9,  3,  3 } };
 122 static const uint32_t nonDiagonalScan8x8ContextOffset[MAX_NUM_CHANNEL_TYPE]   = {  6, 0  };
 123 static const uint32_t notFirstGroupNeighbourhoodContextOffset[MAX_NUM_CHANNEL_TYPE] = { 3, 0 };
 124
 125 // initial probability for cu_transquant_bypass flag
 126 static const uint8_t INIT_CU_TRANSQUANT_BYPASS_FLAG[3][NUM_TQUANT_BYPASS_FLAG_CTX] =
 127 {
 128     { 154 },
 129     { 154 },
 130     { 154 },
 131 };
 132
 133 // initial probability for split flag
 134 static const uint8_t INIT_SPLIT_FLAG[3][NUM_SPLIT_FLAG_CTX] =
 135 {
 136     { 107,  139,  126, },
 137     { 107,  139,  126, },
 138     { 139,  141,  157, },
 139 };
 140
 141 static const uint8_t INIT_SKIP_FLAG[3][NUM_SKIP_FLAG_CTX] =
 142 {
 143     { 197,  185,  201, },
 144     { 197,  185,  201, },
 145     { CNU,  CNU,  CNU, },
 146 };
 147
 148 static const uint8_t INIT_MERGE_FLAG_EXT[3][NUM_MERGE_FLAG_EXT_CTX] =
 149 {
 150     { 154, },
 151     { 110, },
 152     { CNU, },
 153 };
 154
 155 static const uint8_t INIT_MERGE_IDX_EXT[3][NUM_MERGE_IDX_EXT_CTX] =
 156 {
 157     { 137, },
 158     { 122, },
 159     { CNU, },
 160 };
 161
 162 static const uint8_t INIT_PART_SIZE[3][NUM_PART_SIZE_CTX] =
 163 {
 164     { 154,  139,  154, 154 },
 165     { 154,  139,  154, 154 },
 166     { 184,  CNU,  CNU, CNU },
 167 };
 168
 169 static const uint8_t INIT_PRED_MODE[3][NUM_PRED_MODE_CTX] =
 170 {
 171     { 134, },
 172     { 149, },
 173     { CNU, },
 174 };
 175
 176 static const uint8_t INIT_INTRA_PRED_MODE[3][NUM_ADI_CTX] =
 177 {
 178     { 183, },
 179     { 154, },
 180     { 184, },
 181 };
 182
 183 static const uint8_t INIT_CHROMA_PRED_MODE[3][NUM_CHROMA_PRED_CTX] =
 184 {
 185     { 152,  139, },
 186     { 152,  139, },
 187     {  63,  139, },
 188 };
 189
 190 static const uint8_t INIT_INTER_DIR[3][NUM_INTER_DIR_CTX] =
 191 {
 192     {  95,   79,   63,   31,  31, },
 193     {  95,   79,   63,   31,  31, },
 194     { CNU,  CNU,  CNU,  CNU, CNU, },
 195 };
 196
 197 static const uint8_t INIT_MVD[3][NUM_MV_RES_CTX] =
 198 {
 199     { 169,  198, },
 200     { 140,  198, },
 201     { CNU,  CNU, },
 202 };
 203
 204 static const uint8_t INIT_REF_PIC[3][NUM_REF_NO_CTX] =
 205 {
 206     { 153,  153 },
 207     { 153,  153 },
 208     { CNU,  CNU },
 209 };
 210
 211 static const uint8_t INIT_DQP[3][NUM_DELTA_QP_CTX] =
 212 {
 213     { 154,  154,  154, },
 214     { 154,  154,  154, },
 215     { 154,  154,  154, },
 216 };
 217
 218 static const uint8_t INIT_QT_CBF[3][NUM_QT_CBF_CTX] =
 219 {
 220     { 153,  111,  149,   92,  167,  154,  154 },
 221     { 153,  111,  149,  107,  167,  154,  154 },
 222     { 111,  141,   94,  138,  182,  154,  154 },
 223 };
 224
 225 static const uint8_t INIT_QT_ROOT_CBF[3][NUM_QT_ROOT_CBF_CTX] =
 226 {
 227     {  79, },
 228     {  79, },
 229     { CNU, },
 230 };
 231
 232 static const uint8_t INIT_LAST[3][NUM_CTX_LAST_FLAG_XY] =
 233 {
 234     { 125,  110,  124,  110,   95,   94,  125,  111,  111,   79,  125,  126,  111,  111,   79,
 235       108,  123,   93 },
 236     { 125,  110,   94,  110,   95,   79,  125,  111,  110,   78,  110,  111,  111,   95,   94,
 237       108,  123,  108 },
 238     { 110,  110,  124,  125,  140,  153,  125,  127,  140,  109,  111,  143,  127,  111,   79,
 239       108,  123,   63 },
 240 };
 241
 242 static const uint8_t INIT_SIG_CG_FLAG[3][2 * NUM_SIG_CG_FLAG_CTX] =
 243 {
 244     { 121,  140,
 245       61,  154, },
 246     { 121,  140,
 247       61,  154, },
 248     {  91,  171,
 249        134,  141, },
 250 };
 251
 252 static const uint8_t INIT_SIG_FLAG[3][NUM_SIG_FLAG_CTX] =
 253 {
 254     { 170,  154,  139,  153,  139,  123,  123,   63,  124,  166,  183,  140,  136,  153,  154,  166,  183,  140,  136,  153,  154,  166,  183,  140,  136,  153,  154,  170,  153,  138,  138,  122,  121,  122,  121,  167,  151,  183,  140,  151,  183,  140,  },
 255     { 155,  154,  139,  153,  139,  123,  123,   63,  153,  166,  183,  140,  136,  153,  154,  166,  183,  140,  136,  153,  154,  166,  183,  140,  136,  153,  154,  170,  153,  123,  123,  107,  121,  107,  121,  167,  151,  183,  140,  151,  183,  140,  },
 256     { 111,  111,  125,  110,  110,   94,  124,  108,  124,  107,  125,  141,  179,  153,  125,  107,  125,  141,  179,  153,  125,  107,  125,  141,  179,  153,  125,  140,  139,  182,  182,  152,  136,  152,  136,  153,  136,  139,  111,  136,  139,  111,  },
 257 };
 258
 259 static const uint8_t INIT_ONE_FLAG[3][NUM_ONE_FLAG_CTX] =
 260 {
 261     { 154,  196,  167,  167,  154,  152,  167,  182,  182,  134,  149,  136,  153,  121,  136,  122,  169,  208,  166,  167,  154,  152,  167,  182, },
 262     { 154,  196,  196,  167,  154,  152,  167,  182,  182,  134,  149,  136,  153,  121,  136,  137,  169,  194,  166,  167,  154,  167,  137,  182, },
 263     { 140,   92,  137,  138,  140,  152,  138,  139,  153,   74,  149,   92,  139,  107,  122,  152,  140,  179,  166,  182,  140,  227,  122,  197, },
 264 };
 265
 266 static const uint8_t INIT_ABS_FLAG[3][NUM_ABS_FLAG_CTX] =
 267 {
 268     { 107,  167,   91,  107,  107,  167, },
 269     { 107,  167,   91,  122,  107,  167, },
 270     { 138,  153,  136,  167,  152,  152, },
 271 };
 272
 273 static const uint8_t INIT_MVP_IDX[3][NUM_MVP_IDX_CTX] =
 274 {
 275     { 168 },
 276     { 168 },
 277     { CNU },
 278 };
 279
 280 static const uint8_t INIT_SAO_MERGE_FLAG[3][NUM_SAO_MERGE_FLAG_CTX] =
 281 {
 282     { 153,  },
 283     { 153,  },
 284     { 153,  },
 285 };
 286
 287 static const uint8_t INIT_SAO_TYPE_IDX[3][NUM_SAO_TYPE_IDX_CTX] =
 288 {
 289     { 160, },
 290     { 185, },
 291     { 200, },
 292 };
 293
 294 static const uint8_t INIT_TRANS_SUBDIV_FLAG[3][NUM_TRANS_SUBDIV_FLAG_CTX] =
 295 {
 296     { 224,  167,  122, },
 297     { 124,  138,   94, },
 298     { 153,  138,  138, },
 299 };
 300
 301 static const uint8_t INIT_TRANSFORMSKIP_FLAG[3][2 * NUM_TRANSFORMSKIP_FLAG_CTX] =
 302 {
 303     { 139,  139 },
 304     { 139,  139 },
 305     { 139,  139 },
 306 };
 307 }
 308
 309 #endif // ifndef X265_CONTEXTS_H