libavcodec/dct.c File Reference

(Inverse) Discrete Cosine Transforms. More...

#include <math.h>
#include <string.h>
#include "libavutil/mathematics.h"
#include "dct.h"
#include "dct32.h"

Go to the source code of this file.

Defines
#define	SIN(s, n, x)   (s->costab[(n) - (x)])
#define	COS(s, n, x)   (s->costab[x])
Functions
static void	ff_dst_calc_I_c (DCTContext *ctx, FFTSample *data)
static void	ff_dct_calc_I_c (DCTContext *ctx, FFTSample *data)
static void	ff_dct_calc_III_c (DCTContext *ctx, FFTSample *data)
static void	ff_dct_calc_II_c (DCTContext *ctx, FFTSample *data)
static void	dct32_func (DCTContext *ctx, FFTSample *data)
av_cold int	ff_dct_init (DCTContext *s, int nbits, enum DCTTransformType inverse)
	Set up DCT.
av_cold void	ff_dct_end (DCTContext *s)

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Detailed Description

(Inverse) Discrete Cosine Transforms.

These are also known as the type II and type III DCTs respectively.

Definition in file dct.c.

---

Define Documentation

#define COS	(	s,
		n,
		x		)	(s->costab[x])

Definition at line 41 of file dct.c.

Referenced by ff_dct_calc_I_c(), ff_dct_calc_II_c(), and ff_dct_calc_III_c().

#define SIN	(	s,
		n,
		x		)	(s->costab[(n) - (x)])

Definition at line 38 of file dct.c.

Referenced by ff_dct_calc_I_c(), ff_dct_calc_II_c(), ff_dct_calc_III_c(), and ff_dst_calc_I_c().

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Function Documentation

static void dct32_func	(	DCTContext *	ctx,
		FFTSample *	data
	)			[static]

Definition at line 172 of file dct.c.

Referenced by ff_dct_init().

static void ff_dct_calc_I_c	(	DCTContext *	ctx,
		FFTSample *	data
	)			[static]

Definition at line 73 of file dct.c.

Referenced by ff_dct_init().

static void ff_dct_calc_II_c	(	DCTContext *	ctx,
		FFTSample *	data
	)			[static]

Definition at line 136 of file dct.c.

Referenced by ff_dct_init().

static void ff_dct_calc_III_c	(	DCTContext *	ctx,
		FFTSample *	data
	)			[static]

Definition at line 103 of file dct.c.

Referenced by ff_dct_init().

av_cold void ff_dct_end

(

DCTContext *

s

)

Definition at line 218 of file dct.c.

Referenced by decode_end(), main(), and wmavoice_decode_end().

av_cold int ff_dct_init	(	DCTContext *	s,
		int	nbits,
		enum DCTTransformType	type
	)

Set up DCT.

Parameters:

nbits

size of the input array: (1 << nbits) for DCT-II, DCT-III and DST-I (1 << nbits) + 1 for DCT-I

Note:

the first element of the input of DST-I is ignored

Definition at line 177 of file dct.c.

Referenced by decode_init(), ff_mpadsp_init(), main(), and wmavoice_decode_init().

static void ff_dst_calc_I_c	(	DCTContext *	ctx,
		FFTSample *	data
	)			[static]

Definition at line 43 of file dct.c.

Referenced by ff_dct_init().