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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.

Macros

#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 fft_permute_c (FFTContext *s, FFTComplex *z)
 
static void 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.

Macro Definition Documentation

#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 445 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 397 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 407 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 413 of file fft.c.

Referenced by fft16().

#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 422 of file fft.c.

#define BUTTERFLIES   BUTTERFLIES_BIG

Definition at line 445 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 448 of file fft.c.

#define pass   pass_big

Definition at line 511 of file fft.c.

Referenced by decode_nal_units(), encode_frame(), ff_lpc_calc_coefs(), ff_pca(), ff_png_pass_row_size(), ftp_auth(), generate_transition(), gif_read_image(), guess_mv(), h264_handle_packet(), iterative_me(), libssh_open(), new_video_stream(), png_get_interlaced_row(), png_put_interlaced_row(), residue_encode(), and vorbis_residue_decode_internal().

Function Documentation

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 fft_permute_c ( FFTContext *  s,
FFTComplex *  z 
)
static

Definition at line 206 of file fft.c.

Referenced by ff_fft_init().

static void fft_calc_c ( FFTContext *  s,
FFTComplex *  z 
)
static

Definition at line 526 of file fft.c.

Referenced by ff_fft_init().

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

Definition at line 77 of file fft.c.

Referenced by ff_fft_init(), and fft_perm_avx().

av_cold void ff_init_ff_cos_tabs ( int  index)

Initialize the cosine table in ff_cos_tabs[index].

Parameters
indexindex in ff_cos_tabs array of the table to initialize

Definition at line 88 of file fft.c.

static int is_second_half_of_fft32 ( int  i,
int  n 
)
static

Definition at line 106 of file fft.c.

Referenced by fft_perm_avx().

static av_cold void fft_perm_avx ( FFTContext *  s)
static

Definition at line 118 of file fft.c.

Referenced by ff_fft_init().

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

Set up a complex FFT.

Parameters
nbitslog2 of the length of the input array
inverseif 0 perform the forward transform, if 1 perform the inverse

Definition at line 140 of file fft.c.

av_cold void ff_fft_end ( FFTContext *  s)

Definition at line 216 of file fft.c.

static void fft4 ( FFTComplex *  z)
static

Definition at line 457 of file fft.c.

Referenced by fft16(), and fft8().

static void fft8 ( FFTComplex *  z)
static

Definition at line 471 of file fft.c.

Referenced by fft16().

static void fft16 ( FFTComplex *  z)
static

Definition at line 487 of file fft.c.

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 102 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,
}

Definition at line 521 of file fft.c.

Referenced by fft_calc_c().

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