Visible to Intel only — GUID: GUID-9257E098-D935-49D5-89F5-D368334871CA
Visible to Intel only — GUID: GUID-9257E098-D935-49D5-89F5-D368334871CA
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 if pSrc, pDst, or pSrcDst pointer is NULL. |
ippStsStepErr |
Indicates an error condition if srcStep value 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