AVDCT Struct Reference

AVDCT context. More...

#include <avdct.h>

Public Attributes
const AVClass *	av_class
void(*	idct )(int16_t *block)
uint8_t	idct_permutation [64]
	IDCT input permutation. More...
void(*	fdct )(int16_t *block)
int	dct_algo
	DCT algorithm. More...
int	idct_algo
	IDCT algorithm. More...
void(*	get_pixels )(int16_t *block, const uint8_t *pixels, ptrdiff_t line_size)
int	bits_per_sample

Detailed Description

AVDCT context.

Note

function pointers can be NULL if the specific features have been disabled at build time.

Member Data Documentation

dct_algo

int AVDCT::dct_algo

DCT algorithm.

must use AVOptions to set this field.

idct_algo

int AVDCT::idct_algo

IDCT algorithm.

must use AVOptions to set this field.

idct_permutation

uint8_t AVDCT::idct_permutation[64]

IDCT input permutation.

Several optimized IDCTs need a permutated input (relative to the normal order of the reference IDCT). This permutation must be performed before the idct_put/add. Note, normally this can be merged with the zigzag/alternate scan
An example to avoid confusion:

• (->decode coeffs -> zigzag reorder -> dequant -> reference IDCT -> ...)
• (x -> reference DCT -> reference IDCT -> x)
• (x -> reference DCT -> simple_mmx_perm = idct_permutation -> simple_idct_mmx -> x)
• (-> decode coeffs -> zigzag reorder -> simple_mmx_perm -> dequant -> simple_idct_mmx -> ...)

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The documentation for this struct was generated from the following file:

• libavcodec/avdct.h