ContextModel.cpp

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#include <algorithm>

#include "ContextModel.h"

using namespace std;

// ====================================================================================================================
// Public member functions
// ====================================================================================================================

Void ContextModel::init( Int qp, Int initValue )
{
  qp = Clip3(0, 51, qp);

  Int  slope      = (initValue>>4)*5 - 45;
  Int  offset     = ((initValue&15)<<3)-16;
  Int  initState  =  min( max( 1, ( ( ( slope * qp ) >> 4 ) + offset ) ), 126 );
  UInt mpState    = (initState >= 64 );
  m_ucState       = ( (mpState? (initState - 64):(63 - initState)) <<1) + mpState;
}

const UChar ContextModel::m_aucNextStateMPS[ ContextModel::m_totalStates ] =
{
  2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
  18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
  34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
  50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65,
  66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
  82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
  98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113,
  114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 124, 125, 126, 127
};

const UChar ContextModel::m_aucNextStateLPS[ ContextModel::m_totalStates ] =
{
  1, 0, 0, 1, 2, 3, 4, 5, 4, 5, 8, 9, 8, 9, 10, 11,
  12, 13, 14, 15, 16, 17, 18, 19, 18, 19, 22, 23, 22, 23, 24, 25,
  26, 27, 26, 27, 30, 31, 30, 31, 32, 33, 32, 33, 36, 37, 36, 37,
  38, 39, 38, 39, 42, 43, 42, 43, 44, 45, 44, 45, 46, 47, 48, 49,
  48, 49, 50, 51, 52, 53, 52, 53, 54, 55, 54, 55, 56, 57, 58, 59,
  58, 59, 60, 61, 60, 61, 60, 61, 62, 63, 64, 65, 64, 65, 66, 67,
  66, 67, 66, 67, 68, 69, 68, 69, 70, 71, 70, 71, 70, 71, 72, 73,
  72, 73, 72, 73, 74, 75, 74, 75, 74, 75, 76, 77, 76, 77, 126, 127
};

#if FAST_BIT_EST
UChar ContextModel::m_nextState[ ContextModel::m_totalStates ][2 /*MPS = [0|1]*/];

Void ContextModel::buildNextStateTable()
{
  for (Int i = 0; i < ContextModel::m_totalStates; i++)
  {
    for (Int j = 0; j < 2; j++)
    {
      m_nextState[i][j] = ((i&1) == j) ? m_aucNextStateMPS[i] : m_aucNextStateLPS[i];
    }
  }
}
#endif

const Int ContextModel::m_entropyBits[ ContextModel::m_totalStates ] =
{
#if FAST_BIT_EST
  // Corrected table, most notably for last state
  0x07b23, 0x085f9, 0x074a0, 0x08cbc, 0x06ee4, 0x09354, 0x067f4, 0x09c1b, 0x060b0, 0x0a62a, 0x05a9c, 0x0af5b, 0x0548d, 0x0b955, 0x04f56, 0x0c2a9,
  0x04a87, 0x0cbf7, 0x045d6, 0x0d5c3, 0x04144, 0x0e01b, 0x03d88, 0x0e937, 0x039e0, 0x0f2cd, 0x03663, 0x0fc9e, 0x03347, 0x10600, 0x03050, 0x10f95,
  0x02d4d, 0x11a02, 0x02ad3, 0x12333, 0x0286e, 0x12cad, 0x02604, 0x136df, 0x02425, 0x13f48, 0x021f4, 0x149c4, 0x0203e, 0x1527b, 0x01e4d, 0x15d00,
  0x01c99, 0x166de, 0x01b18, 0x17017, 0x019a5, 0x17988, 0x01841, 0x18327, 0x016df, 0x18d50, 0x015d9, 0x19547, 0x0147c, 0x1a083, 0x0138e, 0x1a8a3,
  0x01251, 0x1b418, 0x01166, 0x1bd27, 0x01068, 0x1c77b, 0x00f7f, 0x1d18e, 0x00eda, 0x1d91a, 0x00e19, 0x1e254, 0x00d4f, 0x1ec9a, 0x00c90, 0x1f6e0,
  0x00c01, 0x1fef8, 0x00b5f, 0x208b1, 0x00ab6, 0x21362, 0x00a15, 0x21e46, 0x00988, 0x2285d, 0x00934, 0x22ea8, 0x008a8, 0x239b2, 0x0081d, 0x24577,
  0x007c9, 0x24ce6, 0x00763, 0x25663, 0x00710, 0x25e8f, 0x006a0, 0x26a26, 0x00672, 0x26f23, 0x005e8, 0x27ef8, 0x005ba, 0x284b5, 0x0055e, 0x29057,
  0x0050c, 0x29bab, 0x004c1, 0x2a674, 0x004a7, 0x2aa5e, 0x0046f, 0x2b32f, 0x0041f, 0x2c0ad, 0x003e7, 0x2ca8d, 0x003ba, 0x2d323, 0x0010c, 0x3bfbb
#else
  0x08000, 0x08000, 0x076da, 0x089a0, 0x06e92, 0x09340, 0x0670a, 0x09cdf, 0x06029, 0x0a67f, 0x059dd, 0x0b01f, 0x05413, 0x0b9bf, 0x04ebf, 0x0c35f,
  0x049d3, 0x0ccff, 0x04546, 0x0d69e, 0x0410d, 0x0e03e, 0x03d22, 0x0e9de, 0x0397d, 0x0f37e, 0x03619, 0x0fd1e, 0x032ee, 0x106be, 0x02ffa, 0x1105d,
  0x02d37, 0x119fd, 0x02aa2, 0x1239d, 0x02836, 0x12d3d, 0x025f2, 0x136dd, 0x023d1, 0x1407c, 0x021d2, 0x14a1c, 0x01ff2, 0x153bc, 0x01e2f, 0x15d5c,
  0x01c87, 0x166fc, 0x01af7, 0x1709b, 0x0197f, 0x17a3b, 0x0181d, 0x183db, 0x016d0, 0x18d7b, 0x01595, 0x1971b, 0x0146c, 0x1a0bb, 0x01354, 0x1aa5a,
  0x0124c, 0x1b3fa, 0x01153, 0x1bd9a, 0x01067, 0x1c73a, 0x00f89, 0x1d0da, 0x00eb7, 0x1da79, 0x00df0, 0x1e419, 0x00d34, 0x1edb9, 0x00c82, 0x1f759,
  0x00bda, 0x200f9, 0x00b3c, 0x20a99, 0x00aa5, 0x21438, 0x00a17, 0x21dd8, 0x00990, 0x22778, 0x00911, 0x23118, 0x00898, 0x23ab8, 0x00826, 0x24458,
  0x007ba, 0x24df7, 0x00753, 0x25797, 0x006f2, 0x26137, 0x00696, 0x26ad7, 0x0063f, 0x27477, 0x005ed, 0x27e17, 0x0059f, 0x287b6, 0x00554, 0x29156,
  0x0050e, 0x29af6, 0x004cc, 0x2a497, 0x0048d, 0x2ae35, 0x00451, 0x2b7d6, 0x00418, 0x2c176, 0x003e2, 0x2cb15, 0x003af, 0x2d4b5, 0x0037f, 0x2de55
#endif
};