HuffmanDecodeSegmentOnePass

Performs first pass of video segment decoding, rearranges segment block, multiplies first block element by 128.

Syntax

IppStatus ippiHuffmanDecodeSegmentOnePass_DV_8u16s(const Ipp8u* pStream, const Ipp32u* pZigzagTables, const Ipp32u* pHuffTable, Ipp16s* pBlock, Ipp32u* pBlockParam, Ipp32s nNumCoeffs);

Parameters

pStream	Pointer to bitstream (compressed video segment).
pZigzagTables	Pointer to the array of two scanning matrices.
pHuffTable	Pointer to the decoding Huffman table.
pBlock	Pointer to the array where DCT decoded blocks should be stored.
pBlockParam	Pointer to output parameters array [30].
nNumCoeffs	Maximum number of DCT coefficients to extract from the stream.

Description

This function is declared in the ippvc.h header file. The function ippiHuffmanDecodeSegmentOnePass_DV_8u16s is designed to be used in DV video decoder in a quarter resolution mode. The function performs only the first pass of video segment VLC decoding and extracts not more than specified number of DCT coefficients.

The function accepts the same arguments as the HuffmanDecodeSegment_DV function and one additional parameter - the maximum number of DCT coefficients to extract from the stream, which is passed through the nNumCoeffs argument. If the limit of coefficients is reached during the first pass, the function goes over to the next DCT block. If the limit is not reached during the first pass, the function does not perform the second and the third passes and extracts only the number of DCT coefficients available in the first pass.

The nNumCoeffs parameter must fall within the range of 1 to 64.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one input pointer is NULL.
ippStsBadArgErr	Indicates an error when nNumCoeffs does not fall within the range of 1 through 64.