DecodeDCIntra

Decodes one DC coefficient for intra coded block.

Syntax

IppStatus ippiDecodeDCIntra_MPEG4_1u16s(Ipp8u** ppBitStream, int* pBitOffset, Ipp16s* pDC, int blockType);

Parameters

ppBitStream	Pointer to the pointer to the current byte in the bitstream buffer. The pointer is updated by the function.
pBitOffset	Pointer to the bit position in the byte pointed by **ppBitStream. The pointer is updated by the function.
pDC	Pointer to the output coefficient.
blockType	Indicates the block type, takes one of the following values: IPPVC_BLOCK_LUMA - for luma and alpha blocks, IPPVC_BLOCK_CHROMA - for chroma blocks.

Description

The function ippiDecodeDCIntra_MPEG4_1u16s is declared in the ippvc.h header file. This function performs VLC decoding of the DC coefficient only for one intra coded block using VLC decoding process as specified in [ISO14496], subclause 7.4.1.1.

This function is used in the MPEG-4 decoder included into Intel IPP Samples. See introduction to MPEG-4.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one input pointer is NULL.
ippStsBitOffsetErr	Indicates an error condition if *pBitOffset is out of the range [0, 7].
ippStsVLCCodeErr	Indicates an error condition if an illegal code is detected through the DC decoding.