IIR filter interface. More...

#include "avcodec.h"

Include dependency graph for iirfilter.h:

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Data Structures
struct	FFIIRFilterContext

Typedefs
typedef struct FFIIRFilterContext	FFIIRFilterContext

Enumerations
enum	IIRFilterType { FF_FILTER_TYPE_BESSEL, FF_FILTER_TYPE_BIQUAD, FF_FILTER_TYPE_BUTTERWORTH, FF_FILTER_TYPE_CHEBYSHEV, FF_FILTER_TYPE_ELLIPTIC }

enum	IIRFilterMode { FF_FILTER_MODE_LOWPASS, FF_FILTER_MODE_HIGHPASS, FF_FILTER_MODE_BANDPASS, FF_FILTER_MODE_BANDSTOP }

Functions
void	ff_iir_filter_init (FFIIRFilterContext *f)
	Initialize FFIIRFilterContext. More...

void	ff_iir_filter_init_mips (FFIIRFilterContext *f)

struct FFIIRFilterCoeffs *	ff_iir_filter_init_coeffs (void *avc, enum IIRFilterType filt_type, enum IIRFilterMode filt_mode, int order, float cutoff_ratio, float stopband, float ripple)
	Initialize filter coefficients. More...

struct FFIIRFilterState *	ff_iir_filter_init_state (int order)
	Create new filter state. More...

void	ff_iir_filter_free_coeffs (struct FFIIRFilterCoeffs *coeffs)
	Free filter coefficients. More...

void	ff_iir_filter_free_state (struct FFIIRFilterState *state)
	Free filter state. More...

void	ff_iir_filter (const struct FFIIRFilterCoeffs coeffs, struct FFIIRFilterState state, int size, const int16_t src, int sstep, int16_t dst, int dstep)
	Perform IIR filtering on signed 16-bit input samples. More...

void	ff_iir_filter_flt (const struct FFIIRFilterCoeffs coeffs, struct FFIIRFilterState state, int size, const float src, int sstep, float dst, int dstep)
	Perform IIR filtering on floating-point input samples. More...

Detailed Description

IIR filter interface.

Definition in file iirfilter.h.

Typedef Documentation

typedef struct FFIIRFilterContext FFIIRFilterContext

Enumeration Type Documentation

enum IIRFilterMode

Enumerator
FF_FILTER_MODE_LOWPASS
FF_FILTER_MODE_HIGHPASS
FF_FILTER_MODE_BANDPASS
FF_FILTER_MODE_BANDSTOP

Definition at line 43 of file iirfilter.h.

enum IIRFilterType

Enumerator
FF_FILTER_TYPE_BESSEL
FF_FILTER_TYPE_BIQUAD
FF_FILTER_TYPE_BUTTERWORTH
FF_FILTER_TYPE_CHEBYSHEV
FF_FILTER_TYPE_ELLIPTIC

Definition at line 35 of file iirfilter.h.

Function Documentation

void ff_iir_filter	(	const struct FFIIRFilterCoeffs *	coeffs,
		struct FFIIRFilterState *	state,
		int	size,
		const int16_t *	src,
		int	sstep,
		int16_t *	dst,
		int	dstep
	)

Perform IIR filtering on signed 16-bit input samples.

Parameters

coeffs	pointer to filter coefficients
state	pointer to filter state
size	input length
src	source samples
sstep	source stride
dst	filtered samples (destination may be the same as input)
dstep	destination stride

Definition at line 274 of file iirfilter.c.

Referenced by ff_iir_filter_init().

void ff_iir_filter_flt	(	const struct FFIIRFilterCoeffs *	coeffs,
		struct FFIIRFilterState *	state,
		int	size,
		const float *	src,
		int	sstep,
		float *	dst,
		int	dstep
	)

Perform IIR filtering on floating-point input samples.

Parameters

coeffs	pointer to filter coefficients
state	pointer to filter state
size	input length
src	source samples
sstep	source stride
dst	filtered samples (destination may be the same as input)
dstep	destination stride

Definition at line 287 of file iirfilter.c.

Referenced by ff_iir_filter_init().

void ff_iir_filter_free_coeffs ( struct FFIIRFilterCoeffs * coeffs )

Free filter coefficients.

Parameters

coeffs pointer allocated with ff_iir_filter_init_coeffs()

Definition at line 305 of file iirfilter.c.

Referenced by ff_iir_filter_init(), ff_iir_filter_init_coeffs(), and ff_psy_preprocess_end().

void ff_iir_filter_free_state ( struct FFIIRFilterState * state )

Free filter state.

Parameters

state pointer allocated with ff_iir_filter_init_state()

Definition at line 300 of file iirfilter.c.

Referenced by ff_iir_filter_init(), and ff_psy_preprocess_end().

void ff_iir_filter_init ( FFIIRFilterContext * f )

Initialize FFIIRFilterContext.

Definition at line 314 of file iirfilter.c.

Referenced by ff_psy_preprocess_init().

struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs	(	void *	avc,
		enum IIRFilterType	filt_type,
		enum IIRFilterMode	filt_mode,
		int	order,
		float	cutoff_ratio,
		float	stopband,
		float	ripple
	)

Initialize filter coefficients.

Parameters

avc	a pointer to an arbitrary struct of which the first field is a pointer to an AVClass struct
filt_type	filter type (e.g. Butterworth)
filt_mode	filter mode (e.g. lowpass)
order	filter order
cutoff_ratio	cutoff to input frequency ratio
stopband	stopband to input frequency ratio (used by bandpass and bandstop filter modes)
ripple	ripple factor (used only in Chebyshev filters)