DCT8x8Fwd
Performs a forward DCT on a 2D buffer of 8x8
size.
Syntax
Case 1: Not-in-place operation
IppStatus ippiDCT8x8Fwd_<mod>(const
Ipp<datatype>*
pSrc
, Ipp<datatype>*
pDst
);
Supported values for
mod
:16s_C1 | 32f_C1 |
Case 2: Not-in-place operation with ROI
IppStatus ippiDCT8x8Fwd_<mod>(const
Ipp<srcDatatype>*
pSrc
, int
srcStep
, Ipp<dstDatatype>*
pDst
);
Supported values for
mod
:16s_C1R | 8u16s_C1R |
Case 3: In-place operation
IppStatus
ippiDCT8x8Fwd_<mod>(Ipp<datatype>*
pSrcDst
);
Supported values for
mod
:16s_C1I | 32f_C1I |
Include Files
ippi.h
Domain Dependencies
Headers:
ippcore.h
, ippvm.h
, ipps.h
Libraries:
ippcore.lib
, ippvm.lib
, ipps.lib
Parameters
- pSrc
- Pointer to the source image buffer.
- srcStep
- Distance in bytes between starts of consecutive lines in the source image buffer for operations with ROI.
- pDst
- Pointer to the destination image buffer.
- pSrcDst
- Pointer to the source and destination image for in-place operations.
Description
Some flavors operate with ROI (see Regions of Interest in Intel
IPP).
This function computes the forward discrete cosine transform of
short integer or floating-point data in a 2D buffer of 8x8 size. No prerequisites
are needed to use this transform function.
Return Values
- ippStsNoErr
- Indicates no error. Any other value indicates an error or a warning.
- ippStsNullPtrErr
- Indicates an error condition ifpSrc, pDst,orpSrcDstpointer isNULL.
- ippStsStepErr
- Indicates an error condition ifsrcStepvalue is zero or negative.
Example
The code example below illustrates the use of
ippiDCT8x8Fwd
function. IppStatus dct16s( void ) {
Ipp16s x[64] = {0};
IppiSize roi = {8,8};
int i;
for( i=0; i<8; ++i ) {
ippiSet_16s_C1R( (Ipp16s)i, x+8*i+i, 8*sizeof(Ipp16s), roi );
--roi.width;
--roi.height;
}
return ippiDCT8x8Fwd_16s_C1I( x );
}
The destination image
x
contains:18 -9 -2 -1 -1 0 0 0
-9 7 0 0 0 0 0 0
-2 0 2 0 0 0 0 0
-1 0 0 1 0 0 0 0
0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0