libbpg/jctvc/TLibCommon/ContextModel3DBuffer.cpp
2015-01-16 13:46:18 +01:00

120 lines
5.1 KiB
C++

/* The copyright in this software is being made available under the BSD
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* granted under this license.
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*
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/** \file ContextModel3DBuffer.cpp
\brief context model 3D buffer class
*/
#include "ContextModel3DBuffer.h"
//! \ingroup TLibCommon
//! \{
// ====================================================================================================================
// Constructor / destructor / initialization / destroy
// ====================================================================================================================
ContextModel3DBuffer::ContextModel3DBuffer( UInt uiSizeZ, UInt uiSizeY, UInt uiSizeX, ContextModel *basePtr, Int &count )
: m_sizeX ( uiSizeX )
, m_sizeXY ( uiSizeX * uiSizeY )
, m_sizeXYZ( uiSizeX * uiSizeY * uiSizeZ )
{
// allocate 3D buffer
m_contextModel = basePtr;
count += m_sizeXYZ;
}
// ====================================================================================================================
// Public member functions
// ====================================================================================================================
/**
* Initialize 3D buffer with respect to slicetype, QP and given initial probability table
*
* \param eSliceType slice type
* \param iQp input QP value
* \param psCtxModel given probability table
*/
Void ContextModel3DBuffer::initBuffer( SliceType sliceType, Int qp, UChar* ctxModel )
{
ctxModel += sliceType * m_sizeXYZ;
for ( Int n = 0; n < m_sizeXYZ; n++ )
{
m_contextModel[ n ].init( qp, ctxModel[ n ] );
m_contextModel[ n ].setBinsCoded( 0 );
}
}
/**
* Calculate the cost of choosing a probability table based on the current probability of CABAC at encoder
*
* \param sliceType slice type
* \param qp input QP value
* \param ctxModel given probability table
*/
UInt ContextModel3DBuffer::calcCost( SliceType sliceType, Int qp, UChar* ctxModel )
{
UInt cost = 0;
ctxModel += sliceType * m_sizeXYZ;
for ( Int n = 0; n < m_sizeXYZ; n++ )
{
ContextModel tmpContextModel;
tmpContextModel.init( qp, ctxModel[ n ] );
// Map the 64 CABAC states to their corresponding probability values
static Double aStateToProbLPS[] = {0.50000000, 0.47460857, 0.45050660, 0.42762859, 0.40591239, 0.38529900, 0.36573242, 0.34715948, 0.32952974, 0.31279528, 0.29691064, 0.28183267, 0.26752040, 0.25393496, 0.24103941, 0.22879875, 0.21717969, 0.20615069, 0.19568177, 0.18574449, 0.17631186, 0.16735824, 0.15885931, 0.15079198, 0.14313433, 0.13586556, 0.12896592, 0.12241667, 0.11620000, 0.11029903, 0.10469773, 0.09938088, 0.09433404, 0.08954349, 0.08499621, 0.08067986, 0.07658271, 0.07269362, 0.06900203, 0.06549791, 0.06217174, 0.05901448, 0.05601756, 0.05317283, 0.05047256, 0.04790942, 0.04547644, 0.04316702, 0.04097487, 0.03889405, 0.03691890, 0.03504406, 0.03326442, 0.03157516, 0.02997168, 0.02844963, 0.02700488, 0.02563349, 0.02433175, 0.02309612, 0.02192323, 0.02080991, 0.01975312, 0.01875000};
Double probLPS = aStateToProbLPS[ m_contextModel[ n ].getState() ];
Double prob0, prob1;
if (m_contextModel[ n ].getMps()==1)
{
prob0 = probLPS;
prob1 = 1.0-prob0;
}
else
{
prob1 = probLPS;
prob0 = 1.0-prob1;
}
if (m_contextModel[ n ].getBinsCoded()>0)
{
cost += (UInt) (prob0 * tmpContextModel.getEntropyBits( 0 ) + prob1 * tmpContextModel.getEntropyBits( 1 ));
}
}
return cost;
}
//! \}