dec_tree_dec.c

// Copyright 2010 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Coding trees and probas
//
// Author: Skal (pascal.massimino@gmail.com)

#include "dec_vp8i_dec.h"
#include "utils_bit_reader_inl_utils.h"

#if !defined(USE_GENERIC_TREE)
#if !defined(__arm__) && !defined(_M_ARM) && !defined(__aarch64__)
// using a table is ~1-2% slower on ARM. Prefer the coded-tree approach then.
#define USE_GENERIC_TREE 1   // ALTERNATE_CODE
#else
#define USE_GENERIC_TREE 0
#endif
#endif  // USE_GENERIC_TREE

#if (USE_GENERIC_TREE == 1)
static const int8_t kYModesIntra4[18] = {
  -B_DC_PRED, 1,
    -B_TM_PRED, 2,
      -B_VE_PRED, 3,
        4, 6,
          -B_HE_PRED, 5,
            -B_RD_PRED, -B_VR_PRED,
        -B_LD_PRED, 7,
          -B_VL_PRED, 8,
            -B_HD_PRED, -B_HU_PRED
};
#endif

//------------------------------------------------------------------------------
// Default probabilities

// Paragraph 13.5
static const uint8_t
  CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS] = {
  { { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
    },
    { { 253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128 },
      { 189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128 },
      { 106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128 }
    },
    { { 1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128 },
      { 181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128 },
      { 78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128 },
    },
    { { 1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128 },
      { 184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128 },
      { 77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128 },
    },
    { { 1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128 },
      { 170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128 },
      { 37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128 }
    },
    { { 1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128 },
      { 207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128 },
      { 102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128 }
    },
    { { 1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128 },
      { 177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128 },
      { 80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128 }
    },
    { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
    }
  },
  { { { 198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62 },
      { 131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1 },
      { 68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128 }
    },
    { { 1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128 },
      { 184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128 },
      { 81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128 }
    },
    { { 1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128 },
      { 99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128 },
      { 23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128 }
    },
    { { 1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128 },
      { 109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128 },
      { 44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128 }
    },
    { { 1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128 },
      { 94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128 },
      { 22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128 }
    },
    { { 1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128 },
      { 124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128 },
      { 35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128 }
    },
    { { 1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128 },
      { 121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128 },
      { 45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128 }
    },
    { { 1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128 },
      { 203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
      { 137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128 }
    }
  },
  { { { 253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128 },
      { 175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128 },
      { 73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128 }
    },
    { { 1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128 },
      { 239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128 },
      { 155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128 }
    },
    { { 1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128 },
      { 201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128 },
      { 69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128 }
    },
    { { 1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128 },
      { 223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128 },
      { 141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128 }
    },
    { { 1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
      { 190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128 },
      { 149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
    },
    { { 1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
    },
    { { 1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128 },
      { 213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128 },
      { 55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
    },
    { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
    }
  },
  { { { 202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255 },
      { 126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128 },
      { 61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128 }
    },
    { { 1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128 },
      { 166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128 },
      { 39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128 }
    },
    { { 1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128 },
      { 124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128 },
      { 24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128 }
    },
    { { 1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128 },
      { 149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128 },
      { 28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128 }
    },
    { { 1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128 },
      { 123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128 },
      { 20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128 }
    },
    { { 1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128 },
      { 168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128 },
      { 47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128 }
    },
    { { 1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128 },
      { 141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128 },
      { 42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128 }
    },
    { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
      { 238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
    }
  }
};

// Paragraph 11.5
static const uint8_t kBModesProba[NUM_BMODES][NUM_BMODES][NUM_BMODES - 1] = {
  { { 231, 120, 48, 89, 115, 113, 120, 152, 112 },
    { 152, 179, 64, 126, 170, 118, 46, 70, 95 },
    { 175, 69, 143, 80, 85, 82, 72, 155, 103 },
    { 56, 58, 10, 171, 218, 189, 17, 13, 152 },
    { 114, 26, 17, 163, 44, 195, 21, 10, 173 },
    { 121, 24, 80, 195, 26, 62, 44, 64, 85 },
    { 144, 71, 10, 38, 171, 213, 144, 34, 26 },
    { 170, 46, 55, 19, 136, 160, 33, 206, 71 },
    { 63, 20, 8, 114, 114, 208, 12, 9, 226 },
    { 81, 40, 11, 96, 182, 84, 29, 16, 36 } },
  { { 134, 183, 89, 137, 98, 101, 106, 165, 148 },
    { 72, 187, 100, 130, 157, 111, 32, 75, 80 },
    { 66, 102, 167, 99, 74, 62, 40, 234, 128 },
    { 41, 53, 9, 178, 241, 141, 26, 8, 107 },
    { 74, 43, 26, 146, 73, 166, 49, 23, 157 },
    { 65, 38, 105, 160, 51, 52, 31, 115, 128 },
    { 104, 79, 12, 27, 217, 255, 87, 17, 7 },
    { 87, 68, 71, 44, 114, 51, 15, 186, 23 },
    { 47, 41, 14, 110, 182, 183, 21, 17, 194 },
    { 66, 45, 25, 102, 197, 189, 23, 18, 22 } },
  { { 88, 88, 147, 150, 42, 46, 45, 196, 205 },
    { 43, 97, 183, 117, 85, 38, 35, 179, 61 },
    { 39, 53, 200, 87, 26, 21, 43, 232, 171 },
    { 56, 34, 51, 104, 114, 102, 29, 93, 77 },
    { 39, 28, 85, 171, 58, 165, 90, 98, 64 },
    { 34, 22, 116, 206, 23, 34, 43, 166, 73 },
    { 107, 54, 32, 26, 51, 1, 81, 43, 31 },
    { 68, 25, 106, 22, 64, 171, 36, 225, 114 },
    { 34, 19, 21, 102, 132, 188, 16, 76, 124 },
    { 62, 18, 78, 95, 85, 57, 50, 48, 51 } },
  { { 193, 101, 35, 159, 215, 111, 89, 46, 111 },
    { 60, 148, 31, 172, 219, 228, 21, 18, 111 },
    { 112, 113, 77, 85, 179, 255, 38, 120, 114 },
    { 40, 42, 1, 196, 245, 209, 10, 25, 109 },
    { 88, 43, 29, 140, 166, 213, 37, 43, 154 },
    { 61, 63, 30, 155, 67, 45, 68, 1, 209 },
    { 100, 80, 8, 43, 154, 1, 51, 26, 71 },
    { 142, 78, 78, 16, 255, 128, 34, 197, 171 },
    { 41, 40, 5, 102, 211, 183, 4, 1, 221 },
    { 51, 50, 17, 168, 209, 192, 23, 25, 82 } },
  { { 138, 31, 36, 171, 27, 166, 38, 44, 229 },
    { 67, 87, 58, 169, 82, 115, 26, 59, 179 },
    { 63, 59, 90, 180, 59, 166, 93, 73, 154 },
    { 40, 40, 21, 116, 143, 209, 34, 39, 175 },
    { 47, 15, 16, 183, 34, 223, 49, 45, 183 },
    { 46, 17, 33, 183, 6, 98, 15, 32, 183 },
    { 57, 46, 22, 24, 128, 1, 54, 17, 37 },
    { 65, 32, 73, 115, 28, 128, 23, 128, 205 },
    { 40, 3, 9, 115, 51, 192, 18, 6, 223 },
    { 87, 37, 9, 115, 59, 77, 64, 21, 47 } },
  { { 104, 55, 44, 218, 9, 54, 53, 130, 226 },
    { 64, 90, 70, 205, 40, 41, 23, 26, 57 },
    { 54, 57, 112, 184, 5, 41, 38, 166, 213 },
    { 30, 34, 26, 133, 152, 116, 10, 32, 134 },
    { 39, 19, 53, 221, 26, 114, 32, 73, 255 },
    { 31, 9, 65, 234, 2, 15, 1, 118, 73 },
    { 75, 32, 12, 51, 192, 255, 160, 43, 51 },
    { 88, 31, 35, 67, 102, 85, 55, 186, 85 },
    { 56, 21, 23, 111, 59, 205, 45, 37, 192 },
    { 55, 38, 70, 124, 73, 102, 1, 34, 98 } },
  { { 125, 98, 42, 88, 104, 85, 117, 175, 82 },
    { 95, 84, 53, 89, 128, 100, 113, 101, 45 },
    { 75, 79, 123, 47, 51, 128, 81, 171, 1 },
    { 57, 17, 5, 71, 102, 57, 53, 41, 49 },
    { 38, 33, 13, 121, 57, 73, 26, 1, 85 },
    { 41, 10, 67, 138, 77, 110, 90, 47, 114 },
    { 115, 21, 2, 10, 102, 255, 166, 23, 6 },
    { 101, 29, 16, 10, 85, 128, 101, 196, 26 },
    { 57, 18, 10, 102, 102, 213, 34, 20, 43 },
    { 117, 20, 15, 36, 163, 128, 68, 1, 26 } },
  { { 102, 61, 71, 37, 34, 53, 31, 243, 192 },
    { 69, 60, 71, 38, 73, 119, 28, 222, 37 },
    { 68, 45, 128, 34, 1, 47, 11, 245, 171 },
    { 62, 17, 19, 70, 146, 85, 55, 62, 70 },
    { 37, 43, 37, 154, 100, 163, 85, 160, 1 },
    { 63, 9, 92, 136, 28, 64, 32, 201, 85 },
    { 75, 15, 9, 9, 64, 255, 184, 119, 16 },
    { 86, 6, 28, 5, 64, 255, 25, 248, 1 },
    { 56, 8, 17, 132, 137, 255, 55, 116, 128 },
    { 58, 15, 20, 82, 135, 57, 26, 121, 40 } },
  { { 164, 50, 31, 137, 154, 133, 25, 35, 218 },
    { 51, 103, 44, 131, 131, 123, 31, 6, 158 },
    { 86, 40, 64, 135, 148, 224, 45, 183, 128 },
    { 22, 26, 17, 131, 240, 154, 14, 1, 209 },
    { 45, 16, 21, 91, 64, 222, 7, 1, 197 },
    { 56, 21, 39, 155, 60, 138, 23, 102, 213 },
    { 83, 12, 13, 54, 192, 255, 68, 47, 28 },
    { 85, 26, 85, 85, 128, 128, 32, 146, 171 },
    { 18, 11, 7, 63, 144, 171, 4, 4, 246 },
    { 35, 27, 10, 146, 174, 171, 12, 26, 128 } },
  { { 190, 80, 35, 99, 180, 80, 126, 54, 45 },
    { 85, 126, 47, 87, 176, 51, 41, 20, 32 },
    { 101, 75, 128, 139, 118, 146, 116, 128, 85 },
    { 56, 41, 15, 176, 236, 85, 37, 9, 62 },
    { 71, 30, 17, 119, 118, 255, 17, 18, 138 },
    { 101, 38, 60, 138, 55, 70, 43, 26, 142 },
    { 146, 36, 19, 30, 171, 255, 97, 27, 20 },
    { 138, 45, 61, 62, 219, 1, 81, 188, 64 },
    { 32, 41, 20, 117, 151, 142, 20, 21, 163 },
    { 112, 19, 12, 61, 195, 128, 48, 4, 24 } }
};

void VP8ResetProba(VP8Proba* const proba) {
  memset(proba->segments_, 255u, sizeof(proba->segments_));
  // proba->bands_[][] is initialized later
}

static void ParseIntraMode(VP8BitReader* const br,
                           VP8Decoder* const dec, int mb_x) {
  uint8_t* const top = dec->intra_t_ + 4 * mb_x;
  uint8_t* const left = dec->intra_l_;
  VP8MBData* const block = dec->mb_data_ + mb_x;

  // Note: we don't save segment map (yet), as we don't expect
  // to decode more than 1 keyframe.
  if (dec->segment_hdr_.update_map_) {
    // Hardcoded tree parsing
    block->segment_ = !VP8GetBit(br, dec->proba_.segments_[0], "segments")
                    ?  VP8GetBit(br, dec->proba_.segments_[1], "segments")
                    :  VP8GetBit(br, dec->proba_.segments_[2], "segments") + 2;
  } else {
    block->segment_ = 0;  // default for intra
  }
  if (dec->use_skip_proba_) block->skip_ = VP8GetBit(br, dec->skip_p_, "skip");

  block->is_i4x4_ = !VP8GetBit(br, 145, "block-size");
  if (!block->is_i4x4_) {
    // Hardcoded 16x16 intra-mode decision tree.
    const int ymode =
        VP8GetBit(br, 156, "pred-modes") ?
            (VP8GetBit(br, 128, "pred-modes") ? TM_PRED : H_PRED) :
            (VP8GetBit(br, 163, "pred-modes") ? V_PRED : DC_PRED);
    block->imodes_[0] = ymode;
    memset(top, ymode, 4 * sizeof(*top));
    memset(left, ymode, 4 * sizeof(*left));
  } else {
    uint8_t* modes = block->imodes_;
    int y;
    for (y = 0; y < 4; ++y) {
      int ymode = left[y];
      int x;
      for (x = 0; x < 4; ++x) {
        const uint8_t* const prob = kBModesProba[top[x]][ymode];
#if (USE_GENERIC_TREE == 1)
        // Generic tree-parsing
        int i = kYModesIntra4[VP8GetBit(br, prob[0], "pred-modes")];
        while (i > 0) {
          i = kYModesIntra4[2 * i + VP8GetBit(br, prob[i], "pred-modes")];
        }
        ymode = -i;
#else
        // Hardcoded tree parsing
        ymode = !VP8GetBit(br, prob[0], "pred-modes") ? B_DC_PRED :
                  !VP8GetBit(br, prob[1], "pred-modes") ? B_TM_PRED :
                    !VP8GetBit(br, prob[2], "pred-modes") ? B_VE_PRED :
                      !VP8GetBit(br, prob[3], "pred-modes") ?
                        (!VP8GetBit(br, prob[4], "pred-modes") ? B_HE_PRED :
                          (!VP8GetBit(br, prob[5], "pred-modes") ? B_RD_PRED
                                                                 : B_VR_PRED)) :
                        (!VP8GetBit(br, prob[6], "pred-modes") ? B_LD_PRED :
                          (!VP8GetBit(br, prob[7], "pred-modes") ? B_VL_PRED :
                            (!VP8GetBit(br, prob[8], "pred-modes") ? B_HD_PRED
                                                                   : B_HU_PRED))
                        );
#endif  // USE_GENERIC_TREE
        top[x] = ymode;
      }
      memcpy(modes, top, 4 * sizeof(*top));
      modes += 4;
      left[y] = ymode;
    }
  }
  // Hardcoded UVMode decision tree
  block->uvmode_ = !VP8GetBit(br, 142, "pred-modes-uv") ? DC_PRED
                 : !VP8GetBit(br, 114, "pred-modes-uv") ? V_PRED
                 : VP8GetBit(br, 183, "pred-modes-uv") ? TM_PRED : H_PRED;
}

int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec) {
  int mb_x;
  for (mb_x = 0; mb_x < dec->mb_w_; ++mb_x) {
    ParseIntraMode(br, dec, mb_x);
  }
  return !dec->br_.eof_;
}

//------------------------------------------------------------------------------
// Paragraph 13

static const uint8_t
    CoeffsUpdateProba[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS] = {
  { { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255 },
      { 250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    }
  },
  { { { 217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255 },
      { 234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255 }
    },
    { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    }
  },
  { { { 186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255 },
      { 251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255 }
    },
    { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    }
  },
  { { { 248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255 },
      { 248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    },
    { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
      { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
    }
  }
};

// Paragraph 9.9

static const uint8_t kBands[16 + 1] = {
  0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7,
  0  // extra entry as sentinel
};

void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec) {
  VP8Proba* const proba = &dec->proba_;
  int t, b, c, p;
  for (t = 0; t < NUM_TYPES; ++t) {
    for (b = 0; b < NUM_BANDS; ++b) {
      for (c = 0; c < NUM_CTX; ++c) {
        for (p = 0; p < NUM_PROBAS; ++p) {
          const int v =
              VP8GetBit(br, CoeffsUpdateProba[t][b][c][p], "global-header") ?
                        VP8GetValue(br, 8, "global-header") :
                        CoeffsProba0[t][b][c][p];
          proba->bands_[t][b].probas_[c][p] = v;
        }
      }
    }
    for (b = 0; b < 16 + 1; ++b) {
      proba->bands_ptr_[t][b] = &proba->bands_[t][kBands[b]];
    }
  }
  dec->use_skip_proba_ = VP8Get(br, "global-header");
  if (dec->use_skip_proba_) {
    dec->skip_p_ = VP8GetValue(br, 8, "global-header");
  }
}