Decimator Class Reference

Decimator carries out a fast downsample by a power-of-two factor. More...

#include <Decimator.h>

Public Member Functions
	Decimator (unsigned int inLength, unsigned int decFactor)
	Construct a Decimator to operate on input blocks of length inLength, with decimation factor decFactor.
virtual	~Decimator ()
void	process (const double *src, double *dst)
	Process inLength samples (as supplied to constructor) from src and write inLength / decFactor samples to dst.
void	process (const float *src, float *dst)
	Process inLength samples (as supplied to constructor) from src and write inLength / decFactor samples to dst.
int	getFactor () const
void	resetFilter ()

Static Public Member Functions
static int	getHighestSupportedFactor ()

Private Member Functions
void	deInitialise ()
void	initialise (unsigned int inLength, unsigned int decFactor)
void	doAntiAlias (const double *src, double *dst, unsigned int length)
void	doAntiAlias (const float *src, double *dst, unsigned int length)

Private Attributes
unsigned int	m_inputLength
unsigned int	m_outputLength
unsigned int	m_decFactor
double	Input
double	Output
double	o1
double	o2
double	o3
double	o4
double	o5
double	o6
double	o7
double	a [9]
double	b [9]
double *	decBuffer

Detailed Description

Decimator carries out a fast downsample by a power-of-two factor.

Only a limited number of factors are supported, from two to whatever getHighestSupportedFactor() returns. This is much faster than Resampler but has a worse signal-noise ratio.

Definition at line 24 of file Decimator.h.

Constructor & Destructor Documentation

Decimator()

Decimator::Decimator	(	unsigned int	inLength,
		unsigned int	decFactor )

Construct a Decimator to operate on input blocks of length inLength, with decimation factor decFactor.

inLength should be a multiple of decFactor. Output blocks will be of length inLength / decFactor.

decFactor must be a power of two. The highest supported factor is obtained through getHighestSupportedFactor(); for higher factors, you will need to chain more than one decimator.

Definition at line 24 of file Decimator.cpp.

References initialise(), m_decFactor, m_inputLength, and m_outputLength.

~Decimator()

Decimator::~Decimator ( )

virtual

Definition at line 34 of file Decimator.cpp.

References deInitialise().

Member Function Documentation

process() [1/2]

void Decimator::process	(	const double *	src,
		double *	dst )

Process inLength samples (as supplied to constructor) from src and write inLength / decFactor samples to dst.

Note that src and dst may be the same or overlap (an intermediate buffer is used).

Definition at line 200 of file Decimator.cpp.

References decBuffer, doAntiAlias(), m_decFactor, m_inputLength, and m_outputLength.

process() [2/2]

void Decimator::process	(	const float *	src,
		float *	dst )

Process inLength samples (as supplied to constructor) from src and write inLength / decFactor samples to dst.

Note that src and dst may be the same or overlap (an intermediate buffer is used).

Definition at line 219 of file Decimator.cpp.

References decBuffer, doAntiAlias(), m_decFactor, m_inputLength, and m_outputLength.

getFactor()

int Decimator::getFactor ( ) const

inline

Definition at line 56 of file Decimator.h.

References m_decFactor.

getHighestSupportedFactor()

int Decimator::getHighestSupportedFactor ( )

inlinestatic

Definition at line 57 of file Decimator.h.

Referenced by ClusterMeltSegmenter::initialise(), and DownBeat::makeDecimators().

resetFilter()

void Decimator::resetFilter

(

)

Definition at line 149 of file Decimator.cpp.

References Input, o1, o2, o3, o4, o5, o6, o7, and Output.

Referenced by initialise().

deInitialise()

void Decimator::deInitialise ( )

private

Definition at line 144 of file Decimator.cpp.

References decBuffer.

Referenced by ~Decimator().

initialise()

void Decimator::initialise ( unsigned int inLength, unsigned int decFactor )

private

Definition at line 39 of file Decimator.cpp.

References a, b, decBuffer, m_decFactor, m_inputLength, m_outputLength, and resetFilter().

Referenced by Decimator().

doAntiAlias() [1/2]

void Decimator::doAntiAlias ( const double * src, double * dst, unsigned int length )

private

Definition at line 156 of file Decimator.cpp.

References a, b, Input, o1, o2, o3, o4, o5, o6, o7, and Output.

Referenced by process(), and process().

doAntiAlias() [2/2]

void Decimator::doAntiAlias ( const float * src, double * dst, unsigned int length )

private

Definition at line 178 of file Decimator.cpp.

References a, b, Input, o1, o2, o3, o4, o5, o6, o7, and Output.

Member Data Documentation

m_inputLength

unsigned int Decimator::m_inputLength

private

Definition at line 67 of file Decimator.h.

Referenced by Decimator(), initialise(), process(), and process().

m_outputLength

unsigned int Decimator::m_outputLength

private

Definition at line 68 of file Decimator.h.

Referenced by Decimator(), initialise(), process(), and process().

m_decFactor

unsigned int Decimator::m_decFactor

private

Definition at line 69 of file Decimator.h.

Referenced by Decimator(), getFactor(), initialise(), process(), and process().

Input

double Decimator::Input

private

Definition at line 71 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

Output

double Decimator::Output

private

Definition at line 72 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o1

double Decimator::o1

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o2

double Decimator::o2

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o3

double Decimator::o3

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o4

double Decimator::o4

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o5

double Decimator::o5

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o6

double Decimator::o6

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

o7

double Decimator::o7

private

Definition at line 74 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and resetFilter().

a

double Decimator::a[9]

private

Definition at line 76 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and initialise().

b

double Decimator::b[9]

private

Definition at line 77 of file Decimator.h.

Referenced by doAntiAlias(), doAntiAlias(), and initialise().

decBuffer

double* Decimator::decBuffer

private

Definition at line 79 of file Decimator.h.

Referenced by deInitialise(), initialise(), process(), and process().

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

• Decimator.h
• Decimator.cpp