libavcodec/fft.c File Reference

FFT/IFFT transforms. More...

#include <stdlib.h>
#include <string.h>
#include "libavutil/mathematics.h"
#include "fft.h"
#include "fft-internal.h"

Go to the source code of this file.

Defines

#define BUTTERFLIES(a0, a1, a2, a3)
#define BUTTERFLIES_BIG(a0, a1, a2, a3)
#define TRANSFORM(a0, a1, a2, a3, wre, wim)
#define TRANSFORM_ZERO(a0, a1, a2, a3)
#define PASS(name)
#define BUTTERFLIES   BUTTERFLIES_BIG
#define DECL_FFT(n, n2, n4)
#define pass   pass_big

Functions

 COSTABLE (16)
 COSTABLE (32)
 COSTABLE (64)
 COSTABLE (128)
 COSTABLE (256)
 COSTABLE (512)
 COSTABLE (1024)
 COSTABLE (2048)
 COSTABLE (4096)
 COSTABLE (8192)
 COSTABLE (16384)
 COSTABLE (32768)
 COSTABLE (65536)
COSTABLE_CONST FFTSample *const FFT_NAME (ff_cos_tabs)[]
static void ff_fft_permute_c (FFTContext *s, FFTComplex *z)
static void ff_fft_calc_c (FFTContext *s, FFTComplex *z)
static int split_radix_permutation (int i, int n, int inverse)
av_cold void ff_init_ff_cos_tabs (int index)
 Initialize the cosine table in ff_cos_tabs[index].
static int is_second_half_of_fft32 (int i, int n)
static av_cold void fft_perm_avx (FFTContext *s)
av_cold int ff_fft_init (FFTContext *s, int nbits, int inverse)
 Set up a complex FFT.
av_cold void ff_fft_end (FFTContext *s)
static void fft4 (FFTComplex *z)
static void fft8 (FFTComplex *z)
static void fft16 (FFTComplex *z)

Variables

static const int avx_tab []
static void(*const fft_dispatch [])(FFTComplex *)

Detailed Description

FFT/IFFT transforms.

Definition in file fft.c.

Define Documentation

#define BUTTERFLIES   BUTTERFLIES_BIG

Definition at line 268 of file fft.c.

#define BUTTERFLIES ( a0,
a1,
a2,
a3   ) 

Value:

{\
    BF(t3, t5, t5, t1);\
    BF(a2.re, a0.re, a0.re, t5);\
    BF(a3.im, a1.im, a1.im, t3);\
    BF(t4, t6, t2, t6);\
    BF(a3.re, a1.re, a1.re, t4);\
    BF(a2.im, a0.im, a0.im, t6);\
}

Definition at line 268 of file fft.c.

Referenced by fft8().

#define BUTTERFLIES_BIG ( a0,
a1,
a2,
a3   ) 

Value:

{\
    FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\
    BF(t3, t5, t5, t1);\
    BF(a2.re, a0.re, r0, t5);\
    BF(a3.im, a1.im, i1, t3);\
    BF(t4, t6, t2, t6);\
    BF(a3.re, a1.re, r1, t4);\
    BF(a2.im, a0.im, i0, t6);\
}

Definition at line 220 of file fft.c.

#define DECL_FFT ( n,
n2,
n4   ) 

Value:

static void fft##n(FFTComplex *z)\
{\
    fft##n2(z);\
    fft##n4(z+n4*2);\
    fft##n4(z+n4*3);\
    pass(z,FFT_NAME(ff_cos_##n),n4/2);\
}

Definition at line 271 of file fft.c.

#define pass   pass_big

Definition at line 334 of file fft.c.

Referenced by decode_nal_units(), encode_frame(), ff_lpc_calc_coefs(), ff_pca(), generate_transition(), gif_read_image(), guess_mv(), h264_handle_packet(), residue_encode(), and vorbis_residue_decode_internal().

#define PASS ( name   ) 

Value:

static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
{\
    FFTDouble t1, t2, t3, t4, t5, t6;\
    int o1 = 2*n;\
    int o2 = 4*n;\
    int o3 = 6*n;\
    const FFTSample *wim = wre+o1;\
    n--;\
\
    TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\
    TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
    do {\
        z += 2;\
        wre += 2;\
        wim -= 2;\
        TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\
        TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
    } while(--n);\
}

Definition at line 245 of file fft.c.

#define TRANSFORM ( a0,
a1,
a2,
a3,
wre,
wim   ) 

Value:

{\
    CMUL(t1, t2, a2.re, a2.im, wre, -wim);\
    CMUL(t5, t6, a3.re, a3.im, wre,  wim);\
    BUTTERFLIES(a0,a1,a2,a3)\
}

Definition at line 230 of file fft.c.

Referenced by fft16(), and fft8().

#define TRANSFORM_ZERO ( a0,
a1,
a2,
a3   ) 

Value:

{\
    t1 = a2.re;\
    t2 = a2.im;\
    t5 = a3.re;\
    t6 = a3.im;\
    BUTTERFLIES(a0,a1,a2,a3)\
}

Definition at line 236 of file fft.c.

Referenced by fft16().

Function Documentation

COSTABLE ( 65536   ) 

COSTABLE ( 32768   ) 

COSTABLE ( 16384   ) 

COSTABLE ( 8192   ) 

COSTABLE ( 4096   ) 

COSTABLE ( 2048   ) 

COSTABLE ( 1024   ) 

COSTABLE ( 512   ) 

COSTABLE ( 256   ) 

COSTABLE ( 128   ) 

COSTABLE ( 64   ) 

COSTABLE ( 32   ) 

COSTABLE ( 16   ) 

static void ff_fft_calc_c ( FFTContext *  s,
FFTComplex *  z 
) [static]

Definition at line 349 of file fft.c.

Referenced by ff_fft_init().

av_cold void ff_fft_end ( FFTContext *  s  ) 

Definition at line 202 of file fft.c.

av_cold int ff_fft_init ( FFTContext *  s,
int  nbits,
int  inverse 
)

Set up a complex FFT.

Parameters:
nbits log2 of the length of the input array
inverse if 0 perform the forward transform, if 1 perform the inverse

Definition at line 134 of file fft.c.

static void ff_fft_permute_c ( FFTContext *  s,
FFTComplex *  z 
) [static]

Definition at line 192 of file fft.c.

Referenced by ff_fft_init().

av_cold void ff_init_ff_cos_tabs ( int  index  ) 

Initialize the cosine table in ff_cos_tabs[index].

Parameters:
index index in ff_cos_tabs array of the table to initialize

Definition at line 82 of file fft.c.

static void fft16 ( FFTComplex *  z  )  [static]

Definition at line 310 of file fft.c.

static void fft4 ( FFTComplex *  z  )  [static]

Definition at line 280 of file fft.c.

Referenced by fft16(), and fft8().

static void fft8 ( FFTComplex *  z  )  [static]

Definition at line 294 of file fft.c.

Referenced by fft16().

COSTABLE_CONST FFTSample* const FFT_NAME ( ff_cos_tabs   ) 

static av_cold void fft_perm_avx ( FFTContext *  s  )  [static]

Definition at line 112 of file fft.c.

Referenced by ff_fft_init().

static int is_second_half_of_fft32 ( int  i,
int  n 
) [static]

Definition at line 100 of file fft.c.

Referenced by fft_perm_avx().

static int split_radix_permutation ( int  i,
int  n,
int  inverse 
) [static]

Definition at line 71 of file fft.c.

Referenced by ff_fft_init(), and fft_perm_avx().

Variable Documentation

const int avx_tab[] [static]

Initial value:

 {
    0, 4, 1, 5, 8, 12, 9, 13, 2, 6, 3, 7, 10, 14, 11, 15
}

Definition at line 96 of file fft.c.

Referenced by fft_perm_avx().

void(* const fft_dispatch[])(FFTComplex *) [static]

Initial value:

 {
    fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
    fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
}

Referenced by ff_fft_calc_c().

Generated on Fri Oct 26 02:46:08 2012 for FFmpeg by  doxygen 1.5.8