# Dirac - A Video Codec

Created by the British Broadcasting Corporation.

quant_chooser.h
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37
38
39#ifndef _QUANT_CHOOSER_H_
40#define _QUANT_CHOOSER_H_
41
42#include <libdirac_common/arrays.h>
43#include <libdirac_common/wavelet_utils.h>
44#include <libdirac_common/common.h>
45
46 namespace dirac
47{
49
52 class QuantChooser
53 {
54 public:
55
57 QuantChooser( const CoeffArray& pic_data , const float lambda );
58
60 int GetBestQuant( Subband& node );
61
63 void SetEntropyCorrection( const float ecfac ){ m_entropy_correctionfactor = ecfac; }
64 private:
66 QuantChooser(const QuantChooser& cpy);
67
69 QuantChooser& operator=(const QuantChooser& rhs);
70
72 void IntegralErrorCalc( Subband& node , const int xratio , const int yratio );
73
75 void NonIntegralErrorCalc( Subband& node, const int xratio, const int yratio );
76
78 void LagrangianCalc();
79
81 void SelectBestQuant();
82
83 CoeffType BlockAbsMax( const Subband& node );
84
86 void SetSkip( CodeBlock& cblock , const int qidx);
87
88 private:
90 float m_subband_wt;
91
93 int m_bottom_idx;
95 int m_top_idx;
97 int m_index_step;
98
100 int m_min_idx;
101
103 const CoeffArray& m_coeff_data;
104
106 const float m_lambda;
107
109 float m_entropy_correctionfactor;
110
112 OneDArray<int> m_count0;
114 int m_count1;
116 OneDArray<int> m_countPOS;
118 OneDArray<int> m_countNEG;
120 OneDArray<double> m_error_total;
122 OneDArray<CostType> m_costs;
123
124 };
125
126} // namespace dirac
127
128
129
130#endif
arrays.h
wavelet_utils.h
common.h
dirac
Definition of class SequenceHeaderByteIO.
Definition: accessunit_byteio.h:52
dirac::CoeffType
int CoeffType
Type of wavelet coefficient data (should be larger than ValueType)
Definition: common.h:74
dirac::OneDArray< int >
dirac::CodeBlock
Class for encapsulating metadata concerning a block of coefficients in a subband.
Definition: wavelet_utils.h:60
dirac::Subband
Class encapsulating all the metadata relating to a wavelet subband.
Definition: wavelet_utils.h:140
dirac::CoeffArray
A class for wavelet coefficient data.
Definition: wavelet_utils.h:623
dirac::QuantChooser
Choose a quantiser.
Definition: quant_chooser.h:53
dirac::QuantChooser::QuantChooser
QuantChooser(const QuantChooser &cpy)
Copy constructor is private and body-less. This class should not be copied.
dirac::QuantChooser::m_lambda
const float m_lambda
The lambda value to be used in the Lagrangian calculation.
Definition: quant_chooser.h:106
dirac::QuantChooser::IntegralErrorCalc
void IntegralErrorCalc(Subband &node, const int xratio, const int yratio)
Calculate errors and entropies for integral-bit quantisers.
dirac::QuantChooser::m_top_idx
int m_top_idx
The largest quantisation index being tested.
Definition: quant_chooser.h:95
dirac::QuantChooser::NonIntegralErrorCalc
void NonIntegralErrorCalc(Subband &node, const int xratio, const int yratio)
Calculate errors and entropies for non-integral-bit quantisers.
dirac::QuantChooser::SetEntropyCorrection
void SetEntropyCorrection(const float ecfac)
Sets the factor used for correcting the entropy calculation.
Definition: quant_chooser.h:63
dirac::QuantChooser::operator=
QuantChooser & operator=(const QuantChooser &rhs)
Assignment = is private and body-less. This class should not be assigned.
dirac::QuantChooser::m_entropy_correctionfactor
float m_entropy_correctionfactor
A value for correcting the crude calculation of the entropy.
Definition: quant_chooser.h:109
dirac::QuantChooser::m_count1
int m_count1
The number of ones (equal to the number of coefficients)
Definition: quant_chooser.h:114
dirac::QuantChooser::m_bottom_idx
int m_bottom_idx
The smallest quantisation index being tested.
Definition: quant_chooser.h:93
dirac::QuantChooser::m_subband_wt
float m_subband_wt
The perceptual weighting factor of the subband being tested.
Definition: quant_chooser.h:90
dirac::QuantChooser::GetBestQuant
int GetBestQuant(Subband &node)
Finds the best quantisers for the subband, returning the predicted number of bits needed.
dirac::QuantChooser::LagrangianCalc
void LagrangianCalc()
Having got statistics, calculate the Lagrangian costs.
dirac::QuantChooser::m_error_total
OneDArray< double > m_error_total
An array used to collate the sum of the perceptually-weighted errors.
Definition: quant_chooser.h:120
dirac::QuantChooser::m_count0
OneDArray< int > m_count0
An array used to count the number of zeroes.
Definition: quant_chooser.h:112
dirac::QuantChooser::QuantChooser
QuantChooser(const CoeffArray &pic_data, const float lambda)
Constructor.
dirac::QuantChooser::m_costs
OneDArray< CostType > m_costs
An array used to collate the computed costs.
Definition: quant_chooser.h:122
dirac::QuantChooser::m_countNEG
OneDArray< int > m_countNEG
An array used to count the number of negative values.
Definition: quant_chooser.h:118
dirac::QuantChooser::m_min_idx
int m_min_idx
The index of the quantiser with the lowest cost.
Definition: quant_chooser.h:100
dirac::QuantChooser::SetSkip
void SetSkip(CodeBlock &cblock, const int qidx)
Set the skip flag for a codeblock.
dirac::QuantChooser::m_coeff_data
const CoeffArray & m_coeff_data
A local reference to the data under consideration.
Definition: quant_chooser.h:103
dirac::QuantChooser::SelectBestQuant
void SelectBestQuant()
Select the best quantisation index on the basis of the Lagrangian calculations.
dirac::QuantChooser::m_index_step
int m_index_step
The step we use in jumping through the list of quantisers.
Definition: quant_chooser.h:97
dirac::QuantChooser::m_countPOS
OneDArray< int > m_countPOS
An array used to count the number of positive values.
Definition: quant_chooser.h:116
dirac::QuantChooser::BlockAbsMax
CoeffType BlockAbsMax(const Subband &node)

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