libavcodec/fft.c File Reference

FFT/IFFT transforms. More...

#include "dsputil.h"

Go to the source code of this file.

Defines

#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1)
#define MUL16(a, b)   ((a) * (b))
#define CMUL(pre, pim, are, aim, bre, bim)

Functions

int ff_fft_init (FFTContext *s, int nbits, int inverse)
 The size of the FFT is 2^nbits.
void ff_fft_calc_c (FFTContext *s, FFTComplex *z)
 Do a complex FFT with the parameters defined in ff_fft_init().
void ff_fft_permute (FFTContext *s, FFTComplex *z)
 Do the permutation needed BEFORE calling ff_fft_calc().
void ff_fft_end (FFTContext *s)


Detailed Description

FFT/IFFT transforms.

Definition in file fft.c.


Define Documentation

#define BF ( pre,
pim,
qre,
qim,
pre1,
pim1,
qre1,
qim1   ) 

Value:

{\
  FFTSample ax, ay, bx, by;\
  bx=pre1;\
  by=pim1;\
  ax=qre1;\
  ay=qim1;\
  pre = (bx + ax);\
  pim = (by + ay);\
  qre = (bx - ax);\
  qim = (by - ay);\
}

Definition at line 135 of file fft.c.

#define CMUL ( pre,
pim,
are,
aim,
bre,
bim   ) 

Value:

{\
   pre = (MUL16(are, bre) - MUL16(aim, bim));\
   pim = (MUL16(are, bim) + MUL16(bre, aim));\
}

Definition at line 150 of file fft.c.

#define MUL16 ( a,
 )     ((a) * (b))

Definition at line 148 of file fft.c.


Function Documentation

void ff_fft_calc_c ( FFTContext s,
FFTComplex z 
)

Do a complex FFT with the parameters defined in ff_fft_init().

The input data must be permuted before with s->revtab table. No 1.0/sqrt(n) normalization is done.

Definition at line 161 of file fft.c.

Referenced by ff_fft_init().

void ff_fft_end ( FFTContext s  ) 

Definition at line 256 of file fft.c.

Referenced by ff_mdct_end(), imc_decode_close(), main(), and qdm2_decode_close().

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

The size of the FFT is 2^nbits.

If inverse is TRUE, inverse FFT is done

Definition at line 33 of file fft.c.

Referenced by ff_mdct_init(), imc_decode_init(), main(), and qdm2_decode_init().

void ff_fft_permute ( FFTContext s,
FFTComplex z 
)

Do the permutation needed BEFORE calling ff_fft_calc().

Definition at line 238 of file fft.c.

Referenced by imc_imdct256(), main(), and qdm2_calculate_fft().


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