Example of Using VLC Coding Functions

The functions ippsVLCCountBits and ippsVLCEncodeBlock can be simply used in the wide range of different encoders (for example, for audio data). For example, if you need to quantize some vectors and encode them using no more bits than specified, these functions can be used as follows:

previously the table inputTable of the size inputTableSize must be created; this table is of the following format:

static IppsVLCTable_32s inputTable[]=

{value0, code0, length0};

{value1, code1, length1};

...

{valueN, codeN, lengthN};

initialization step:

ippsVLCEncodeGetSize_32s(InputTable, inputTableSize, &Size);

pVLCSpec = ippsMalloc_8u(Size); /* memory allocation */

ippsVLCEncodeInit_32s(pInputTable, inputTableSize, pVLCSpec);

...

counting bits step:

Do {

//A some quantization algorithm should be here. Let pSrc is output of this algorithm.

...

ippsVLCCountBits_16s32s(pSrc, srcLen, &bitNumber, pVLCSpec);

} while (bitNumber > allowedBitNumber);

encoding bit stream step:

ippsVLCEncodeBlock_16s1u (pSrc, srcLen, ppBitStream, pBitStreamBitsOffset, pVLCSpec);