source: 3DVCSoftware/trunk/source/Lib/TLibCommon/ContextModel.cpp @ 236

/* The copyright in this software is being made available under the BSD
 * License, included below. This software may be subject to other third party
 * and contributor rights, including patent rights, and no such rights are
 * granted under this license.  
 *
 * Copyright (c) 2010-2012, ITU/ISO/IEC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  * Neither the name of the ITU/ISO/IEC nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

/** \file     ContextModel.cpp
    \brief    context model class
*/

#include <algorithm>

#include "ContextModel.h"

using namespace std;
//! \ingroup TLibCommon
//! \{

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

/**
 - initialize context model with respect to QP and initialization value
 .
 \param  qp         input QP value
 \param  initValue  8 bit initialization value
 */
Void ContextModel::init( Int qp, Int initValue )
{
#if H0736_AVC_STYLE_QP_RANGE
  qp = Clip3(0, 51, qp);
#endif

#if CABAC_LINEAR_INIT
  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;
#else
  Int m = m_slopes[initValue>>4];
  Int n = initValue & 15;
  
  Int val = max( 0, min( 3839, (n<<8) + m * (qp-26) + 128 ) );
  val -= 1920;
  Int valMps = val >= 0;
  val = ( val ^ (val>>11) ) + 128;
  Int segmentIdx = val >> 8;
  Int pStateIdx = m_accumulatedSegOffset[segmentIdx] + ( (val&255) * m_segOffset[segmentIdx] >> 8);
  
  m_ucState = (pStateIdx<<1) + valMps;
#endif
}

const UChar ContextModel::m_aucNextStateMPS[ 128 ] =
{
  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[ 128 ] =
{
  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[128][2];

Void ContextModel::buildNextStateTable()
{
  for (Int i = 0; i < 128; 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[128] =
{
#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
};
#if !CABAC_LINEAR_INIT
const Int ContextModel::m_slopes[16] = { -239, -143, -85, -51, -31, -19, -11, 0, 11, 19, 31, 51, 85, 143, 239, 399 };
const Int ContextModel::m_segOffset[8]            = {   6,  7,  5,  7, 10, 14, 16,  1 };
const Int ContextModel::m_accumulatedSegOffset[8] = {  -3,  3, 10, 15, 22, 32, 46, 62 };
#endif
//! \}