QuantInter

Performs quantization on an inter coded block.

Syntax

IppStatus ippiQuantInter_H263_16s_C1I(Ipp16s* pSrcDst, int QP, int* pCountNonZero, int modQuantFlag);

Parameters

pSrcDst	Pointer to the coefficient buffer of the block.
QP	Quantization parameter.
pCountNonZero	Pointer to the number of non-zero coefficients after quantization.
modQuantFlag	Flag equal to a non-zero value when Modified Quantization mode is in use, equal to 0 otherwise.

Description

The function ippiQuantInter_H263_16s_C1I is declared in the ippvc.h header file. This function performs quantization on an inter coded block according to H.263 standard. The standard specifies dequantization process, while quantization decision levels are not defined. The DCT coefficients are reconstructed using equally spaced levels with a central dead-zone around zero and with a step size of 2*QP ([[ITUH263], subclauses 4.2.4, 6.2). When not in Modified Quantization mode, the quantized coefficients are clipped to the range [-127, 127].

This function is used in the H.261, H.263, and MPEG-4 encoders included into Intel IPP Samples. See introduction to H.263.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error condition if at least one of the specified pointers is NULL.
ippStsQPErr	Indicates an error condition if QP is out of the range [1, 31].