libavcodec/fft.c File Reference

FFT/IFFT transforms. More...

#include "dsputil.h"

Go to the source code of this file.

Defines

#define sqrthalf   (float)M_SQRT1_2
#define BF(x, y, a, b)
#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

 DECLARE_ALIGNED_16 (FFTSample, ff_cos_16[8])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_32[16])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_64[32])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_128[64])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_256[128])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_512[256])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_1024[512])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_2048[1024])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_4096[2048])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_8192[4096])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_16384[8192])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_32768[16384])
 DECLARE_ALIGNED_16 (FFTSample, ff_cos_65536[32768])
static int split_radix_permutation (int i, int n, int inverse)
av_cold int ff_fft_init (FFTContext *s, int nbits, int inverse)
 Sets up a complex FFT.
void ff_fft_permute_c (FFTContext *s, FFTComplex *z)
av_cold void ff_fft_end (FFTContext *s)
static void fft4 (FFTComplex *z)
static void fft8 (FFTComplex *z)
static void fft16 (FFTComplex *z)
void ff_fft_calc_c (FFTContext *s, FFTComplex *z)

Variables

FFTSample * ff_cos_tabs []
static void(* fft_dispatch [])(FFTComplex *)

Detailed Description

FFT/IFFT transforms.

Definition in file fft.c.

Define Documentation

#define BF ( x,
y,
a,
b   ) 

Value:

{\
    x = a - b;\
    y = a + b;\
}

Definition at line 219 of file fft.c.

#define BUTTERFLIES   BUTTERFLIES_BIG

Definition at line 286 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 286 of file fft.c.

#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 236 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,ff_cos_##n,n4/2);\
}

Definition at line 289 of file fft.c.

#define pass   pass_big

Definition at line 355 of file fft.c.

Referenced by encode_frame(), ff_lpc_calc_coefs(), ff_pca(), gif_read_image(), guess_mv(), h264_handle_packet(), iterative_me(), opt_pass(), residue_encode(), and vorbis_residue_decode_internal().

#define PASS ( name   ) 

Value:

static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
{\
    FFTSample 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 263 of file fft.c.

#define sqrthalf   (float)M_SQRT1_2

Definition at line 217 of file fft.c.

Referenced by fft16(), and fft8().

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

Value:

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

Definition at line 246 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 254 of file fft.c.

Referenced by fft16().

Function Documentation

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_65536  [32768] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_32768  [16384] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_16384  [8192] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_8192  [4096] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_4096  [2048] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_2048  [1024] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_1024  [512] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_512  [256] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_256  [128] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_128  [64] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_64  [32] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_32  [16] 
)

DECLARE_ALIGNED_16 ( FFTSample  ,
ff_cos_16  [8] 
)

void ff_fft_calc_c ( FFTContext *  s,
FFTComplex *  z 
)

Definition at line 370 of file fft.c.

Referenced by ff_fft_init().

av_cold void ff_fft_end ( FFTContext *  s  ) 

Definition at line 209 of file fft.c.

Referenced by ff_mdct_end(), ff_rdft_end(), imc_decode_close(), and main().

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

Sets 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 61 of file fft.c.

Referenced by ff_mdct_init(), ff_rdft_init(), imc_decode_init(), and main().

void ff_fft_permute_c ( FFTContext *  s,
FFTComplex *  z 
)

Definition at line 184 of file fft.c.

Referenced by ff_fft_init().

static void fft16 ( FFTComplex *  z  )  [static]

Definition at line 333 of file fft.c.

static void fft4 ( FFTComplex *  z  )  [static]

Definition at line 298 of file fft.c.

Referenced by fft16(), and fft8().

static void fft8 ( FFTComplex *  z  )  [static]

Definition at line 312 of file fft.c.

Referenced by fft16().

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

Definition at line 50 of file fft.c.

Referenced by ff_fft_init().

Variable Documentation

FFTSample* ff_cos_tabs[]

Initial value:

 {
    ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,
    ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
}

Definition at line 45 of file fft.c.

Referenced by ff_fft_init(), and ff_rdft_init().

void(* 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().

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