libavcodec/dct.c File Reference

(Inverse) Discrete Cosine Transforms. More...

#include <math.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)


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,
 )     (s->costab[x])

Definition at line 40 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,
 )     (s->costab[(n) - (x)])

Definition at line 37 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().


Function Documentation

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

Definition at line 171 of file dct.c.

Referenced by ff_dct_init().

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

Definition at line 72 of file dct.c.

Referenced by ff_dct_init().

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

Definition at line 135 of file dct.c.

Referenced by ff_dct_init().

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

Definition at line 102 of file dct.c.

Referenced by ff_dct_init().

av_cold void ff_dct_end ( DCTContext s  ) 

Definition at line 217 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 176 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 42 of file dct.c.

Referenced by ff_dct_init().


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