QuantInvIntra_MPEG4, QuantInvInter_MPEG4

Perform inverse quantization on intra/inter coded block.

Syntax

IppStatus ippiQuantInvIntra_MPEG4_16s_C1I(Ipp16s* pCoeffs, int indxLastNonZero, const IppiQuantIntraSpec_MPEG4* pSpec, int QP, int blockType);

IppStatus ippiQuantInvInter_MPEG4_16s_C1I(Ipp16s* pCoeffs, int indxLastNonZero, const IppiQuantInterSpec_MPEG4* pSpec, int QP);

Parameters

pCoeffs

Pointer to the quantized DCT coefficients.

indxLastNonZero

Index of the last non-zero coefficient. This parameter provides faster operation. If the value is unknown, set to 63.

pSpec

Pointer to the initialized specification structure IppiQuantInvIntraSpec_MPEG4 or IppiQuantInvInterSpec_MPEG4 initialized by ippiQuantInvIntraInit_MPEG4 or ippiQuantInvInterInit_MPEG4 respectively.

QP

Quantization parameter.

blockType

Indicates the block type. Takes one of the following values: IPPVC_BLOCK_LUMA - for lume and alpha blocks, IPPVC_BLOCK_CHROMA - for chroma blocks.

pSrcDst

Pointer to the coefficient buffer of intra/inter block. Contains quantized coefficients (QF) on input and dequantized coefficients (F) on output.

pQPMatrix

Pointer to the quantization weighting matrix. If pQPMatrix is NULL, this function will use the second inverse quantization method; otherwise, it will use the first method.

videoComp

(Intra version only) Video component type of the current block. It is used for DC coefficient dequantizing. Takes one of the following flags: IPP_VIDEO_LUMINANCE, IPP_VIDEO_CHROMINANCE, IPP_VIDEO_ALPHA.

Description

The functions ippiQuantInvIntra_MPEG4_16s_C1I and ippiQuantInvInter_MPEG4_16s_C1I are declared in the ippvc.h file. These functions perform inverse quantization on intra/inter coded block, saturation and mismatch control (for the first inverse quantization method only) as it is specified in [ISO14496], subclause 7.4.4.

For ippiQuantInvIntra_MPEG4_16s_C1I and ippiQuantInvInter_MPEG4_16s_C1I output coefficients are saturated to lie in range [-2bitsPerPixel+3; 2bitsPerPixel+3 - 1] .

These functions are used in the MPEG-4 encoder and decoder included into Intel IPP Samples. See introduction to MPEG-4.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error condition if at least one pointer is NULL.

ippStsQPErr

Indicates an error condition if QP is out of the range [1, 2bitsPerPixel-3 - 1].


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