EncodeHuffman8x8_ACFirst

Performs progressive encoding of the AC coefficients from an 8x8 block of the quantized DCT coefficients (first scan).

Syntax

IppStatus ippiEncodeHuffman8x8_ACFirst_JPEG_16s1u_C1(const Ipp16s* pSrc, Ipp8u* pDst, int dstLenBytes, int* pDstCurrPos, int Ss, int Se, int Al, IppiEncodeHuffmanSpec* pAcTable, IppiEncodeHuffmanState* pEncHuffState, int bFlushState);

Parameters

pSrc	Pointer to the 8x8 block of the quantized DCT coefficients
pDst	Pointer to the buffer for the output bit stream.
dstLenBytes	Length in bytes of the buffer for the bit stream.
pDstCurrPos	Shift in bytes of the current byte in the output buffer.
Ss	Spectral selection start index.
Se	Spectral selection end index.
Al	Successive approximation bit positions low, it specifies the actual point transform.
pAcTable	Pointer to the Huffman table for AC coefficients.
pEncHuffState	Pointer to the IppiEncodeHuffmanState structure.
bFlushState	Set it to 1 for the last 8x8 block in the scan.

Description

The function ippiEncodeHuffman8x8_ACFirst_JPEG is declared in the ippj.h file. This function performs encoding of the AC coefficients from an 8x8 block of the quantized DCT coefficients (progressive encoding, the first scan), using pAcTable table. The encoding procedure conforms to [ISO10918], Annex G.1.2, Progressive Encoding Procedures with Huffman. Only full bytes are written to the output buffer. The IppiEncodeHuffmanState structure collects the bits that do not make up a complete byte. To force adding the bits accumulated in IppiEncodeHuffmanState to the output buffer, set the parameter bFlushState to 1 for the last 8x8 block in the scan or restart interval being encoded. In all other cases it must be set to zero.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error condition if one or all of the specified pointers are NULL.
ippStsJPEGOutOfBufErr	Indicates an error condition if the buffer limits are exceeded.
ippStsJPEGDCTRangeErr	Indicates an error condition if the DCT coefficient is out of the allowed range (-1023..1023).