iirfilter.h File Reference

IIR filter interface. More...

#include <stddef.h>
#include <stdint.h>

Go to the source code of this file.

Data Structures
struct	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_coeffsp (struct FFIIRFilterCoeffs **coeffs)
	Free filter coefficients. More...
void	ff_iir_filter_free_statep (struct FFIIRFilterState **state)
	Free and zero filter state. More...
void	ff_iir_filter (const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state, int size, const int16_t *src, ptrdiff_t sstep, int16_t *dst, ptrdiff_t 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, ptrdiff_t sstep, float *dst, ptrdiff_t dstep)
	Perform IIR filtering on floating-point input samples. More...

Detailed Description

IIR filter interface.

Definition in file iirfilter.h.

Enumeration Type Documentation

IIRFilterType

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 36 of file iirfilter.h.

IIRFilterMode

enum IIRFilterMode

Enumerator
FF_FILTER_MODE_LOWPASS
FF_FILTER_MODE_HIGHPASS
FF_FILTER_MODE_BANDPASS
FF_FILTER_MODE_BANDSTOP

Definition at line 44 of file iirfilter.h.

Function Documentation

ff_iir_filter_init()

void ff_iir_filter_init

(

FFIIRFilterContext *

f

)

Initialize FFIIRFilterContext.

Definition at line 322 of file iirfilter.c.

Referenced by ff_psy_preprocess_init().

ff_iir_filter_init_mips()

void ff_iir_filter_init_mips

(

FFIIRFilterContext *

f

)

Definition at line 203 of file iirfilter_mips.c.

Referenced by ff_iir_filter_init().

ff_iir_filter_init_coeffs()

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)

Returns

pointer to filter coefficients structure or NULL if filter cannot be created

Definition at line 162 of file iirfilter.c.

Referenced by ff_psy_preprocess_init(), and main().

ff_iir_filter_init_state()

struct FFIIRFilterState* ff_iir_filter_init_state

(

int

order

)

Create new filter state.

Parameters

order

filter order

Returns

pointer to new filter state or NULL if state creation fails

Definition at line 204 of file iirfilter.c.

Referenced by ff_psy_preprocess_init(), and main().

ff_iir_filter_free_coeffsp()

void ff_iir_filter_free_coeffsp

(

struct FFIIRFilterCoeffs **

coeffs

)

Free filter coefficients.

Parameters

coeffs

pointer allocated with ff_iir_filter_init_coeffs()

Definition at line 312 of file iirfilter.c.

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

ff_iir_filter_free_statep()

void ff_iir_filter_free_statep

(

struct FFIIRFilterState **

state

)

Free and zero filter state.

Parameters

state

pointer to pointer allocated with ff_iir_filter_init_state()

Definition at line 307 of file iirfilter.c.

Referenced by ff_psy_preprocess_end(), and main().

ff_iir_filter()

void ff_iir_filter	(	const struct FFIIRFilterCoeffs *	coeffs,
		struct FFIIRFilterState *	state,
		int	size,
		const int16_t *	src,
		ptrdiff_t	sstep,
		int16_t *	dst,
		ptrdiff_t	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 279 of file iirfilter.c.

Referenced by main().

ff_iir_filter_flt()

void ff_iir_filter_flt	(	const struct FFIIRFilterCoeffs *	coeffs,
		struct FFIIRFilterState *	state,
		int	size,
		const float *	src,
		ptrdiff_t	sstep,
		float *	dst,
		ptrdiff_t	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 293 of file iirfilter.c.

Referenced by ff_iir_filter_init().