Computes the DCT-IV of a signal.
Syntax
IppStatus ippgDCT4_32f(const Ipp32f* pSrc, Ipp32f* pDst, const IppgDCT4Spec_32f* pSpec);
IppStatus ippgDCT4_64f(const Ipp64f* pSrc, Ipp64f* pDst, const IppsDCT4Spec_64f* pSpec);
Parameters
pSpec |
Pointer to the DCT-IV specification structure. |
pSrc |
Pointer to the source vector. |
pDst |
Pointer to the destination vector. |
Description
The function ippgDCT4 is declared in the ippgen.h file. This function computes the type-IV discrete cosine transform (DCT-IV) of the source signal pSrc in accordance with the specification structure pSpec that must be initialized by calling the functions ippgDCT4InitAlloc or ippgDCT4Init beforehand. The result in stored in the pDst. The DCT-IV is its own inverse, or involutary transform.
In the following definition of DCT-IV, N = len,
x(n) is pSrc[n] and y(k) is pDst[k].
The DCT-IV is defined by the formula [Rao90]:
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error if one of the pSpec, pSrc, pDst pointers is NULL. |
ippStsContextMatchErr |
Indicates an error if the specification identifier pSpec is incorrect. |
ippStsMemAllocErr |
Indicates an error if memory allocation fails. |