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

Data Structures
struct	AVComplexFloat

struct	AVComplexDouble

struct	AVComplexInt32

Typedefs
typedef void(*	av_tx_fn) (AVTXContext s, void out, void *in, ptrdiff_t stride)
	Function pointer to a function to perform the transform. More...

Enumerations
enum	AVTXType { AV_TX_FLOAT_FFT = 0, AV_TX_FLOAT_MDCT = 1, AV_TX_DOUBLE_FFT = 2, AV_TX_DOUBLE_MDCT = 3, AV_TX_INT32_FFT = 4, AV_TX_INT32_MDCT = 5 }

enum	AVTXFlags { AV_TX_INPLACE = 1ULL << 0, AV_TX_UNALIGNED = 1ULL << 1, AV_TX_FULL_IMDCT = 1ULL << 2 }
	Flags for av_tx_init() More...

Functions
int	av_tx_init (AVTXContext *ctx, av_tx_fn tx, enum AVTXType type, int inv, int len, const void *scale, uint64_t flags)
	Initialize a transform context with the given configuration (i)MDCTs with an odd length are currently not supported. More...

void	av_tx_uninit (AVTXContext **ctx)
	Frees a context and sets ctx to NULL, does nothing when ctx == NULL. More...

Typedef Documentation

◆ av_tx_fn

typedef void(* av_tx_fn) (AVTXContext *s, void *out, void *in, ptrdiff_t stride)

Function pointer to a function to perform the transform.

Note: Using a different context than the one allocated during av_tx_init() is not allowed.

Parameters

s	the transform context
out	the output array
in	the input array
stride	the input or output stride in bytes

The out and in arrays must be aligned to the maximum required by the CPU architecture unless the AV_TX_UNALIGNED flag was set in av_tx_init(). The stride must follow the constraints the transform type has specified.

Definition at line 102 of file tx.h.

Enumeration Type Documentation

◆ AVTXType

enum AVTXType

Enumerator
AV_TX_FLOAT_FFT	Standard complex to complex FFT with sample data type AVComplexFloat. Output is not 1/len normalized. Scaling currently unsupported. The stride parameter is ignored.
AV_TX_FLOAT_MDCT	Standard MDCT with sample data type of float and a scale type of float. Length is the frame size, not the window size (which is 2x frame) For forward transforms, the stride specifies the spacing between each sample in the output array in bytes. The input must be a flat array. For inverse transforms, the stride specifies the spacing between each sample in the input array in bytes. The output will be a flat array. Stride must be a non-zero multiple of sizeof(float). NOTE: the inverse transform is half-length, meaning the output will not contain redundant data. This is what most codecs work with. To do a full inverse transform, set the AV_TX_FULL_IMDCT flag on init.
AV_TX_DOUBLE_FFT	Same as AV_TX_FLOAT_FFT with a data type of AVComplexDouble.
AV_TX_DOUBLE_MDCT	Same as AV_TX_FLOAT_MDCT with data and scale type of double. Stride must be a non-zero multiple of sizeof(double).
AV_TX_INT32_FFT	Same as AV_TX_FLOAT_FFT with a data type of AVComplexInt32.
AV_TX_INT32_MDCT	Same as AV_TX_FLOAT_MDCT with data type of int32_t and scale type of float. Only scale values less than or equal to 1.0 are supported. Stride must be a non-zero multiple of sizeof(int32_t).

Definition at line 39 of file tx.h.

◆ AVTXFlags

enum AVTXFlags

Flags for av_tx_init()

Enumerator

AV_TX_INPLACE

Performs an in-place transformation on the input.

The output argument of av_tn_fn() MUST match the input. May be unsupported or slower for some transform types.

AV_TX_UNALIGNED

Relaxes alignment requirement for the in and out arrays of av_tx_fn().

May be slower with certain transform types.

AV_TX_FULL_IMDCT

Performs a full inverse MDCT rather than leaving out samples that can be derived through symmetry.

Requires an output array of 'len' floats, rather than the usual 'len/2' floats. Ignored for all transforms but inverse MDCTs.

Definition at line 107 of file tx.h.

Function Documentation

◆ av_tx_init()

int av_tx_init	(	AVTXContext **	ctx,
		av_tx_fn *	tx,
		enum AVTXType	type,
		int	inv,
		int	len,
		const void *	scale,
		uint64_t	flags
	)

Initialize a transform context with the given configuration (i)MDCTs with an odd length are currently not supported.

Parameters

ctx	the context to allocate, will be NULL on error
tx	pointer to the transform function pointer to set
type	type the type of transform
inv	whether to do an inverse or a forward transform
len	the size of the transform in samples
scale	pointer to the value to scale the output if supported by type
flags	a bitmask of AVTXFlags or 0

Returns: 0 on success, negative error code on failure

Definition at line 228 of file tx.c.

Referenced by config_input(), config_output(), convert_coeffs(), decode_init(), load_data(), and siren_init().

◆ av_tx_uninit()

void av_tx_uninit ( AVTXContext ** ctx )

Frees a context and sets ctx to NULL, does nothing when ctx == NULL.

Definition at line 213 of file tx.c.

Referenced by av_tx_init(), common_uninit(), config_output(), decode_close(), free_tx_refs(), load_data(), siren_close(), and uninit().

Data Structures

Typedefs

Enumerations

Functions