dirac::QuantChooser Class Reference

Choose a quantiser. More...

#include <quant_chooser.h>

Collaboration diagram for dirac::QuantChooser:

[legend]

List of all members.

Public Member Functions

• QuantChooser (const CoeffArray &pic_data, const float lambda)

  Constructor.
  

• int GetBestQuant (Subband &node)

  Finds the best quantisers for the subband, returning the predicted number of bits needed.
  

• void SetEntropyCorrection (const float ecfac)

  Sets the factor used for correcting the entropy calculation.
  

Private Member Functions

• QuantChooser (const QuantChooser &cpy)

  Copy constructor is private and body-less. This class should not be copied.
  

• QuantChooser & operator= (const QuantChooser &rhs)

  Assignment = is private and body-less. This class should not be assigned.
  

• void IntegralErrorCalc (Subband &node, const int xratio, const int yratio)

  Calculate errors and entropies for integral-bit quantisers.
  

• void NonIntegralErrorCalc (Subband &node, const int xratio, const int yratio)

  Calculate errors and entropies for non-integral-bit quantisers.
  

• void LagrangianCalc ()

  Having got statistics, calculate the Lagrangian costs.
  

• void SelectBestQuant ()

  Select the best quantisation index on the basis of the Lagrangian calculations.
  

• CoeffType BlockAbsMax (const Subband &node)
• void SetSkip (CodeBlock &cblock, const int qidx)

  Set the skip flag for a codeblock.
  

Private Attributes

• float m_subband_wt

  The perceptual weighting factor of the subband being tested.
  

• int m_bottom_idx

  The smallest quantisation index being tested.
  

• int m_top_idx

  The largest quantisation index being tested.
  

• int m_index_step

  The step we use in jumping through the list of quantisers.
  

• int m_min_idx

  The index of the quantiser with the lowest cost.
  

• const CoeffArray & m_coeff_data

  A local reference to the data under consideration.
  

• const float m_lambda

  The lambda value to be used in the Lagrangian calculation.
  

• float m_entropy_correctionfactor

  A value for correcting the crude calculation of the entropy.
  

• OneDArray< int > m_count0

  An array used to count the number of zeroes.
  

• int m_count1

  The number of ones (equal to the number of coefficients).
  

• OneDArray< int > m_countPOS

  An array used to count the number of positive values.
  

• OneDArray< int > m_countNEG

  An array used to count the number of negative values.
  

• OneDArray< double > m_error_total

  An array used to collate the sum of the perceptually-weighted errors.
  

• OneDArray< CostType > m_costs

  An array used to collate the computed costs.
  

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Detailed Description

This class chooses a quantiser or quantisers for a subband

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Constructor & Destructor Documentation

dirac::QuantChooser::QuantChooser	(	const CoeffArray &	pic_data,
		const float	lambda
	)

dirac::QuantChooser::QuantChooser

(

const QuantChooser &

cpy

)

[private]

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Member Function Documentation

CoeffType dirac::QuantChooser::BlockAbsMax

(

const Subband &

node

)

[private]

int dirac::QuantChooser::GetBestQuant

(

Subband &

node

)

void dirac::QuantChooser::IntegralErrorCalc	(	Subband &	node,
		const int	xratio,
		const int	yratio
	)			[private]

void dirac::QuantChooser::LagrangianCalc

(

)

[private]

void dirac::QuantChooser::NonIntegralErrorCalc	(	Subband &	node,
		const int	xratio,
		const int	yratio
	)			[private]

QuantChooser& dirac::QuantChooser::operator=

(

const QuantChooser &

rhs

)

[private]

void dirac::QuantChooser::SelectBestQuant

(

)

[private]

void dirac::QuantChooser::SetEntropyCorrection

(

const float

ecfac

)

[inline]

References m_entropy_correctionfactor.

void dirac::QuantChooser::SetSkip	(	CodeBlock &	cblock,
		const int	qidx
	)			[private]

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Member Data Documentation

int dirac::QuantChooser::m_bottom_idx [private]

const CoeffArray& dirac::QuantChooser::m_coeff_data [private]

OneDArray<CostType> dirac::QuantChooser::m_costs [private]

OneDArray<int> dirac::QuantChooser::m_count0 [private]

int dirac::QuantChooser::m_count1 [private]

OneDArray<int> dirac::QuantChooser::m_countNEG [private]

OneDArray<int> dirac::QuantChooser::m_countPOS [private]

float dirac::QuantChooser::m_entropy_correctionfactor [private]

Referenced by SetEntropyCorrection().

OneDArray<double> dirac::QuantChooser::m_error_total [private]

int dirac::QuantChooser::m_index_step [private]

const float dirac::QuantChooser::m_lambda [private]

int dirac::QuantChooser::m_min_idx [private]

float dirac::QuantChooser::m_subband_wt [private]

int dirac::QuantChooser::m_top_idx [private]

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The documentation for this class was generated from the following file:

• quant_chooser.h