mlib_SignalFFTW_2(3MLIB) mediaLib Library Functions mlib_SignalFFTW_2(3MLIB)NAME
mlib_SignalFFTW_2, mlib_SignalFFTW_2_S16_S16, mlib_Sig‐
nalFFTW_2_S16C_S16C, mlib_SignalFFTW_2_S16C_S16, mlib_SignalFFTW_2_S16,
mlib_SignalFFTW_2_S16C, mlib_SignalFFTW_2_F32_F32, mlib_Sig‐
nalFFTW_2_F32C_F32C, mlib_SignalFFTW_2_F32C_F32, mlib_SignalFFTW_2_F32,
mlib_SignalFFTW_2_F32C - signal Fast Fourier Transform with windowing
(FFTW)
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_SignalFFTW_2_S16_S16(mlib_s16 *dstr, mlib_s16 *dsti,
const mlib_s16 *srcr, const mlib_s16 *srci, const mlib_s16 *window,
mlib_s32 order);
mlib_status mlib_SignalFFTW_2_S16C_S16C(mlib_s16 *dstc,
const mlib_s16 *srcc,const mlib_s16 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_S16C_S16(mlib_s16 *dstc,
const mlib_s16 *srcr,const mlib_s16 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_S16(mlib_s16 *srcdstr,
mlib_s16 *srcdsti,const mlib_s16 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_S16C(mlib_s16 *srcdstc,
const mlib_s16 *window,mlib_s32 order);
mlib_status mlib_SignalFFTW_2_F32_F32(mlib_f32 *dstr, mlib_f32 *dsti,
const mlib_f32 *srcr, const mlib_f32 *srci, const mlib_f32 *
window,mlib_s32 order);
mlib_status mlib_SignalFFTW_2_F32C_F32C(mlib_f32 *dstc,
const mlib_f32 *srcc,const mlib_f32 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_F32C_F32(mlib_f32 *dstc,
const mlib_f32 *srcr,const mlib_f32 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_F32(mlib_f32 *srcdstr,
mlib_f32 *srcdsti,const mlib_f32 *window, mlib_s32 order);
mlib_status mlib_SignalFFTW_2_F32C(mlib_f32 *srcdstc,
const mlib_f32 *window,mlib_s32 order);
DESCRIPTION
Each of the functions in this group performs Fast Fourier Transform
with windowing (FFTW).
The FFTW functions use the following equation:
1 N-1
dst[k] = ---- SUM {src[n] * window[n] * exp(-j2*PI*n*k/N)}
C1 n=0
and the IFFTW functions use the following equation:
1 N-1
dst[n] = ---- SUM {src[k] * window[k] * exp(j2*PI*n*k/N)}
C2 k=0
where
k = 0, 1, ..., (N - 1)
n = 0, 1, ..., (N - 1)
N = 2**order
The signal FFTW/IFFTW functions can be categorized into four groups
according to the ScaleMode in the function names in the following form:
mlib_Signal[FFTW|IFFTW]_ScaleMode_OutType_InType_OpMode()
mlib_Signal[FFTW|IFFTW]_ScaleMode_DataType_OpMode()
The scaling factors C1 and C2 used in the equations are defined as fol‐
lows:
o For ScaleMode = 1, C1 = 1 and C2 = 2**order.
o For ScaleMode = 2, C1 = 2**order and C2 = 1.
o For ScaleMode = 3, C1 = C2 = 2**(order/2) when order is
even, or C1 = 2**((order+1)/2) and C2 = 2**((order-1)/2)
when order is odd.
o For ScaleMode = 4, C1 = 2**P and C2 = 2**Q, where P and Q
are adaptive scaling factors and are generated by the func‐
tions.
For functions with only real parts for the source signal, the imaginary
parts are assumed to be all zero. For functions with only real parts
for the destination signal, the imaginary parts are discarded. The
functions with only one data type in their names perform the operation
in place.
PARAMETERS
Each function takes some of the following arguments:
dstr Destination signal array that contains the real parts.
dsti Destination signal array that contains the imaginary parts.
srcr Source signal array that contains the real parts.
srci Source signal array that contains the imaginary parts.
dstc Complex destination signal array. dstc[2*i] contains the
real parts, and dstc[2*i+1] contains the imaginary parts.
srcc Complex source signal array. srcc[2*i] contains the real
parts, and srcc[2*i+1] contains the imaginary parts.
srcdstr Source and destination signal array that contains the real
parts.
srcdsti Source and destination signal array that contains the imagi‐
nary parts.
srcdstc Complex source and destination signal array. srcdstc[2*i]
contains the real parts, and srcdstc[2*i+1] contains the
imaginary parts.
window Window coefficient array with 2**order real elements. The
window coefficients are in Q15 format for the S16 data type,
or in float format for the F32 data type.
order Order of the transformation. The base-2 logarithm of the
number of data samples.
RETURN VALUES
Each function returns MLIB_SUCCESS if successful. Otherwise it returns
MLIB_FAILURE.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmlib_SignalFFTW_1(3MLIB), mlib_SignalFFTW_3(3MLIB), mlib_Sig‐
nalFFTW_4(3MLIB), mlib_SignalIFFTW_1(3MLIB), mlib_SignalIFFTW_2(3MLIB),
mlib_SignalIFFTW_3(3MLIB), mlib_SignalIFFTW_4(3MLIB), attributes(5)SunOS 5.10 2 Mar 2007 mlib_SignalFFTW_2(3MLIB)
