Perform an inverse DCT on a 2D buffer of 8x8 size with further downsampling to 2x2 or 4x4 size.
Syntax
IppStatus ippiDCT8x8To2x2Inv_16s_C1(const Ipp16s* pSrc, Ipp16s* pDst);
IppStatus ippiDCT8x8To4x4Inv_16s_C1(const Ipp16s* pSrc, Ipp16s* pDst);
IppStatus ippiDCT8x8To2x2Inv_16s_C1I(Ipp16s* pSrcDst);
IppStatus ippiDCT8x8To4x4Inv_16s_C1I(Ipp16s* pSrcDst);
Parameters
pSrc |
Pointer to the source image. |
pDst |
Pointer to the destination buffer. |
pSrcDst |
Pointer to the source and destination buffer for in-place operations. |
Description
The functions ippiDCT8x8To2x2Inv and ippiDCT8x8To4x4Inv are declared in the ippi.h file. These functions compute the inverse discrete cosine transform of the 2D buffer pSrc of 8x8 size. Then the functions perform downsampling of the result by averaging to the destination buffer pDst of size 2x2 or 4x4.
In-place flavors of the functions perform operations on the source and destination buffer pSrcDst.
Caution
Source data for 16s flavors must be the result of the forward discrete cosine transform of data from the range [-256, 255], they cannot be arbitrary data from the range [-32768, 32767].
Return Values
ippStsNoErr |
Indicates no error. Any other value indicates an error. |
ippStsNullPtrErr |
Indicates an error condition if one of the specified pointers is NULL. |