ojph::param_qcd Class Reference

Quantization parameters object. More...

#include <ojph_params.h>

Public Types
enum	comp_type : ui8 { OJPH_COMP_Y = 0 , OJPH_COMP_CB = 1 , OJPH_COMP_CR = 2 , OJPH_COMP_UNDEFINED = 0xFF }

Public Member Functions
	param_qcd (local::param_qcd *p)
void	set_irrev_quant (float delta)
	Set the irreversible quantization base delta.
void	set_irrev_quant (float delta, size_t num_weights, const float weights[])
	Set the irreversible reference quantization step size delta_r and weight coefficients sqrt(w_b) for all components.
void	set_qfactor (float qfactor)
	Sets Qfactor.
void	set_irrev_quant (ui32 comp_idx, float delta, size_t num_weights, const float weights[])
	Set the irreversible reference quantization step size delta_r and weight coefficients sqrt(w_b) for a specific component.
void	set_irrev_quant (ui32 comp_idx, float delta)
	Set the irreversible quantization base delta for a specific component.
void	set_qfactor (ui32 comp_idx, comp_type ctype, float qfactor)
	Sets Qfactor for a specific component.

Static Public Member Functions
static comp_type	ui8_2_comp_type (ui8 c)

Private Attributes
local::param_qcd *	state

Detailed Description

Quantization parameters object.

Definition at line 169 of file ojph_params.h.

Member Enumeration Documentation

comp_type

enum ojph::param_qcd::comp_type : ui8

Enumerator
OJPH_COMP_Y
OJPH_COMP_CB
OJPH_COMP_CR
OJPH_COMP_UNDEFINED

Definition at line 172 of file ojph_params.h.

Constructor & Destructor Documentation

param_qcd()

ojph::param_qcd::param_qcd ( local::param_qcd * p )

inline

Definition at line 186 of file ojph_params.h.

References state.

Referenced by ojph::codestream::access_qcd().

Member Function Documentation

set_irrev_quant() [1/4]

void ojph::param_qcd::set_irrev_quant

(

float

delta

)

Set the irreversible quantization base delta.

This represents the default base delta and influences QCD marker segment

Parameters

delta

Definition at line 413 of file ojph_params.cpp.

References ojph::local::param_qcd::set_delta(), and state.

Referenced by LLVMFuzzerTestOneInput(), main(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), TEST(), and TEST().

set_irrev_quant() [2/4]

void ojph::param_qcd::set_irrev_quant	(	float	delta,
		size_t	num_weights,
		const float	weights[] )

Set the irreversible reference quantization step size delta_r and weight coefficients sqrt(w_b) for all components.

See also

set_irrev_quant(ui32, float, float*, size_t)

Parameters

delta	Reference quantization step size delta_r
num_weights	Number of coefficients in weights
weights	Array of weight coefficients sqrt(w_b) in subband order

Definition at line 419 of file ojph_params.cpp.

References ojph::local::param_qcd::set_delta(), and state.

set_irrev_quant() [3/4]

void ojph::param_qcd::set_irrev_quant	(	ui32	comp_idx,
		float	delta )

Set the irreversible quantization base delta for a specific component.

This represents the default base delta for component comp_idx, and influences QCC marker segment for the component, inserting one if needed, which is usually the case.

Parameters

comp_idx
delta

Definition at line 431 of file ojph_params.cpp.

References ojph::local::param_qcd::set_delta(), and state.

set_irrev_quant() [4/4]

void ojph::param_qcd::set_irrev_quant	(	ui32	comp_idx,
		float	delta,
		size_t	num_weights,
		const float	weights[] )

Set the irreversible reference quantization step size delta_r and weight coefficients sqrt(w_b) for a specific component.

The quantization step size delta_b for subband b is given by: delta_b = delta_r / sqrt(G_b * w_b * M_c) where G_b is the energy gain factor for the sub-band synthesis operator, w_b is the visual weight, and M_c accounts for the gain from the MCT/ICT. The b corresponds to the subband order:

{LH1, HL1, HH1, LH2, HL2, HH2 … , HHN, LLN}

Parameters

comp_idx	Target component
delta	Reference quantization step size delta_r
num_weights	Number of coefficients in weights
weights	Array of weight coefficients sqrt(w_b) in subband order

Definition at line 437 of file ojph_params.cpp.

References ojph::local::param_qcd::set_delta(), and state.

set_qfactor() [1/2]

void ojph::param_qcd::set_qfactor

(

float

qfactor

)

Sets Qfactor.

This is a top level Qfactor; it will automatically set the qfactor; if you have one or two channels they will be set to luminance (or Y) visual weighting. If you have three or more, the first three will be set to Y, Cb, Cr; channels 4 onwards will be set to luminance. If that does not match the desired behaviour; then do not set the top level qfactor, but set the Qfactor for individual channels according to desired visual weighting type, using set_qfactor(ui32 comp_idx, comp_type ctype, float qfactor);

Note that setting Qfactor takes precedence over setting an irreversible quantization base delta.

Parameters

qfactor

Compression quality as an integer between 1 (worst quality) and 100 (best quality)

Definition at line 426 of file ojph_params.cpp.

References ojph::local::param_qcd::set_qfactor(), and state.

Referenced by main(), TEST(), TEST(), TEST(), TEST(), TEST(), and TEST().

set_qfactor() [2/2]

void ojph::param_qcd::set_qfactor	(	ui32	comp_idx,
		comp_type	ctype,
		float	qfactor )

Sets Qfactor for a specific component.

Setting Qfactor takes precedence over setting an irreversible quantization base delta

Parameters

comp_idx	Component index
ctype	Indicates whether the component is a Y, Cb or Cr channel, after the ICT if present
qfactor	Compression quality as an integer between 1 (worst quality) and 100 (best quality)

Definition at line 444 of file ojph_params.cpp.

References ojph::local::param_qcd::set_qfactor(), and state.

ui8_2_comp_type()

comp_type ojph::param_qcd::ui8_2_comp_type ( ui8 c )

inlinestatic

Definition at line 178 of file ojph_params.h.

References OJPH_COMP_CR, OJPH_COMP_UNDEFINED, and OJPH_COMP_Y.

Referenced by ojph::local::param_qcd::check_validity().

Member Data Documentation

state

local::param_qcd* ojph::param_qcd::state

private

Definition at line 279 of file ojph_params.h.

Referenced by param_qcd(), set_irrev_quant(), set_irrev_quant(), set_irrev_quant(), set_irrev_quant(), set_qfactor(), and set_qfactor().

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

• /build/openjph/src/OpenJPH/src/core/openjph/ojph_params.h
• /build/openjph/src/OpenJPH/src/core/codestream/ojph_params.cpp