mlib_SignalIFFTW_1_S16_S16C(3mlib)

1mlib_SignalIFFTW_1(3MLIB) mediaLib Library Functions mlib_SignalIFFTW_1(3MLIB)
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NAME

6       mlib_SignalIFFTW_1,        mlib_SignalIFFTW_1_S16_S16,        mlib_Sig‐
7       nalIFFTW_1_S16C_S16C,      mlib_SignalIFFTW_1_S16_S16C,       mlib_Sig‐
8       nalIFFTW_1_S16,   mlib_SignalIFFTW_1_S16C,  mlib_SignalIFFTW_1_F32_F32,
9       mlib_SignalIFFTW_1_F32C_F32C,  mlib_SignalIFFTW_1_F32_F32C,   mlib_Sig‐
10       nalIFFTW_1_F32,  mlib_SignalIFFTW_1_F32C  - signal Inverse Fast Fourier
11       Transform with windowing (IFFTW)
12

SYNOPSIS

14       cc [ flag... ] file... -lmlib [ library... ]
15       #include <mlib.h>
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17       mlib_status mlib_SignalIFFTW_1_S16_S16(mlib_s16 *dstr, mlib_s16 *dsti,
18            const mlib_s16 *srcr, const mlib_s16 *srci, const mlib_s16 *window,
19            mlib_s32 order);
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22       mlib_status mlib_SignalIFFTW_1_S16C_S16C(mlib_s16 *dstc,
23            const mlib_s16 *srcc,
24            const mlib_s16 *window, mlib_s32 order);
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26
27       mlib_status mlib_SignalIFFTW_1_S16_S16C(mlib_s16 *dstr,
28            const mlib_s16 *srcc,
29            const mlib_s16 *window, mlib_s32 order);
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32       mlib_status mlib_SignalIFFTW_1_S16(mlib_s16 *srcdstr, mlib_s16 *srcdsti,
33            const mlib_s16 *window, mlib_s32 order);
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36       mlib_status mlib_SignalIFFTW_1_S16C(mlib_s16 *srcdstc,
37            const mlib_s16 *window,
38            mlib_s32 order);
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41       mlib_status mlib_SignalIFFTW_1_F32_F32(mlib_f32 *dstr,
42            mlib_f32 *dsti,
43            const mlib_f32 *srcr, const mlib_f32 *srci, const mlib_f32 *window,
44            mlib_s32 order);
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46
47       mlib_status mlib_SignalIFFTW_1_F32C_F32C(mlib_f32 *dstc,
48            const mlib_f32 *srcc,
49            const mlib_f32 *window, mlib_s32 order);
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51
52       mlib_status mlib_SignalIFFTW_1_F32_F32C(mlib_f32 *dstr,
53            const mlib_f32 *srcc,
54            const mlib_f32 *window, mlib_s32 order);
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57       mlib_status mlib_SignalIFFTW_1_F32(mlib_f32 *srcdstr, mlib_f32 *srcdsti,
58            const mlib_f32 *window, mlib_s32 order);
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61       mlib_status mlib_SignalIFFTW_1_F32C(mlib_f32 *srcdstc,
62            const mlib_f32 *window,
63            mlib_s32 order);
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DESCRIPTION

67       Each of the functions in  this  group  performs  Inverse  Fast  Fourier
68       Transform with windowing (IFFTW).
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70
71       The FFTW functions use the following equation:
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73                   1   N-1
74         dst[k] = ---- SUM {src[n] * window[n] * exp(-j2*PI*n*k/N)}
75                   C1  n=0
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77
78
79       and the IFFTW functions use the following equation:
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81                   1   N-1
82         dst[n] = ---- SUM {src[k] * window[k] * exp(j2*PI*n*k/N)}
83                   C2  k=0
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87       where
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89         k = 0, 1, ..., (N - 1)
90         n = 0, 1, ..., (N - 1)
91         N = 2**order
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95       The  signal  FFTW/IFFTW  functions  can be categorized into four groups
96       according to the ScaleMode in the function names in the following form:
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98         mlib_Signal[FFTW|IFFTW]_ScaleMode_OutType_InType_OpMode()
99         mlib_Signal[FFTW|IFFTW]_ScaleMode_DataType_OpMode()
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103       The scaling factors C1 and C2 used in the equations are defined as fol‐
104       lows:
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106           o      For ScaleMode = 1, C1 = 1 and C2 = 2**order.
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108           o      For ScaleMode = 2, C1 = 2**order and C2 = 1.
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110           o      For  ScaleMode  =  3,  C1  = C2 = 2**(order/2) when order is
111                  even, or C1 = 2**((order+1)/2)  and  C2  =  2**((order-1)/2)
112                  when order is odd.
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114           o      For  ScaleMode  =  4, C1 = 2**P and C2 = 2**Q, where P and Q
115                  are adaptive scaling factors and are generated by the  func‐
116                  tions.
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118
119       For functions with only real parts for the source signal, the imaginary
120       parts are assumed to be all zero. For functions with  only  real  parts
121       for  the  destination  signal,  the  imaginary parts are discarded. The
122       functions with only one data type in their names perform the  operation
123       in place.
124

PARAMETERS

126       Each function takes some of the following arguments:
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128       dstr       Destination signal array that contains the real parts.
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131       dsti       Destination signal array that contains the imaginary parts.
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134       srcr       Source signal array that contains the real parts.
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137       srci       Source signal array that contains the imaginary parts.
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140       dstc       Complex  destination  signal  array.  dstc[2*i] contains the
141                  real parts, and dstc[2*i+1] contains the imaginary parts.
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144       srcc       Complex source signal array.  srcc[2*i]  contains  the  real
145                  parts, and srcc[2*i+1] contains the imaginary parts.
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148       srcdstr    Source  and  destination signal array that contains the real
149                  parts.
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152       srcdsti    Source and destination signal array that contains the imagi‐
153                  nary parts.
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156       srcdstc    Complex  source  and  destination signal array. srcdstc[2*i]
157                  contains the real parts,  and  srcdstc[2*i+1]  contains  the
158                  imaginary parts.
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161       window     Window  coefficient  array  with 2**order real elements. The
162                  window coefficients are in Q15 format for the S16 data type,
163                  or in float format for the F32 data type.
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166       order      Order  of  the  transformation.  The base-2 logarithm of the
167                  number of data samples.
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169

RETURN VALUES

171       Each function returns MLIB_SUCCESS if successful. Otherwise it  returns
172       MLIB_FAILURE.
173

ATTRIBUTES

175       See attributes(5) for descriptions of the following attributes:
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180       ┌─────────────────────────────┬─────────────────────────────┐
181       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
182       ├─────────────────────────────┼─────────────────────────────┤
183       │Interface Stability          │Committed                    │
184       ├─────────────────────────────┼─────────────────────────────┤
185       │MT-Level                     │MT-Safe                      │
186       └─────────────────────────────┴─────────────────────────────┘
187

NAME

SYNOPSIS

DESCRIPTION

PARAMETERS

RETURN VALUES

ATTRIBUTES

SEE ALSO