DCTInvInit

Initializes the inverse discrete cosine transform structure.

Syntax

IppStatus ippsDCTInvInit_16s(IppsDCTInvSpec_16s** ppDCTSpec, int len, IppHintAlgorithm hint, Ipp8u* pSpec, Ipp8u* pSpecBuffer);

IppStatus ippsDCTInvInit_32f(IppsDCTInvSpec_32f** ppDCTSpec, int len, IppHintAlgorithm hint, Ipp8u* pSpec, Ipp8u* pSpecBuffer);

IppStatus ippsDCTInvInit_64f(IppsDCTInvSpec_64f** ppDCTSpec, int len, IppHintAlgorithm hint, Ipp8u* pSpec, Ipp8u* pSpecBuffer);

Parameters

ppDCTSpec	Double pointer to the inverse DCT specification structure to be created.
len	Number of samples in the DCT.
hint	Suggests using specific code for calculation. The values for the hint argument are described in the section Flag and Hint Arguments.
pSpec	Pointer to the area for the DCT specification structure.
pSpecBuffer	Pointer to the work buffer, can be NULL.

Description

The function ippsDCTInvInit is declared in the ipps.h file. This function initializes in the buffer pSpec the inverse DCT specification structure ppDCTSpec with the following parameters: the transform len, and the specific code hint.

Before calling this function the memory must be allocated for the DCT specification structure and the work buffer (if it is required). The size of the DFT specification structure and the work buffer must be computed by the function ippsDCTInvGetSize.

If the work buffer is not used, the parameter pSpecBuffer can be NULL. If the working buffer is used, the parameter pSpecBuffer must not be NULL.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointers with exception of pSpecBuffer is NULL.
ippStsSizeErr	Indicates an error when len is less than or equal to 0.