QuantIntra

Performs quantization on DCT coefficients for intra blocks in-place with specified quantization matrix according to MPEG-2 standard.

Syntax

IppStatus ippiQuantIntra_MPEG2_16s_C1I(Ipp16s* pSrcDst, Ipp32s QP, const Ipp32f* pQPMatrix, Ipp32s* pCount);

Parameters

pSrcDst	Pointer to the block of DCT coefficients.
QP	Quantizer.
pQPMatrix	Pointer to the matrix of inverted quantization coefficients.
pCount	Number of the non-zero AC coefficients after quantization.

Description

This function is declared in the ippvc.h header file. The in-place function ippiQuantIntra_MPEG2_16s_C1I multiplies all DCT coefficients in block except DC coefficients by the elements of the inverted quantization matrix and divide them by quantizer. The number of non-zero coefficients after quantization is stored in pCount for future considerations. If the pointer pQPMatrix is NULL, then the default matrix is used.

This function is used in the MPEG-2 encoder included into Intel IPP Samples. See introduction to MPEG-1 and MPEG-2.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one input pointer is NULL.
ippStsDivByZeroErr	Indicates an error when quantizer QP is equal to zero.