QuantWeightBlockInv_DV

Syntax

Parameters

Note

There are two different types of blocks: 8x8 and 2x4x8. Select respective weighting tables for 8x8 or 2x4x8 blocks.

Description

This function is declared in the ippvc.h header file. The function ippiQuantWeightBlockInv_DV_16s_C1I performs inverse quantization and inverse weighting on a block in accordance with [SMPTE314M] standard.

The DV frame decoding process is depicted in "BlockParam Structure". The ippiQuantWeightBlockInv_DV_16s_C1I function covers de-quantization and inverse weighting steps. Choose appropriate quantization and weighting tables, that is, dequantization and deweighting tables for decoding. To choose the quantization table, use the values of two parameters - qno (quantization number) and the block quant class. For details, see [SMPTE314M], Table 23 - Quantization step. Use different weighting tables for 8x8 and 2x4x8 blocks.

The ippiQuantWeightBlockInv_DV_16s_C1I function uses the following three pointers as input arguments:

The function performs the following operations:

for (Ipp32s i = 0;i < 64;i += 1) pDataBlock[i] = (Ipp16s) ( ( ((Ipp16s) pDataBlock [1]>>3 ) * ((Ipp16s) pQuantTable[i] ) * ((Ipp16s) pWeightTable[i] ) )>>16);

The pWeightTable weighting table contains floating point data with values varying from 2.0 to 4.0. Scaling is required for integer multiplication through multiplying the table values by 8192 (1<<13). Then back shift is required through division by 65536 to provide for REAL range, that is, to perform inverse scaling.

After ippiQuantWeightBlockInv_DV_16s_C1I completes dequantization and inverse weighing, iDCT is performed before creating the macroblock.

Compare QuantInv_DV and QuantWeightBlockInv_DV. The ippiQuantInv_DV_16s_C1I function has two arguments: pDataBlock, which is a pointer to the current block, and pQuantTable, a modification of the quantization table with values multiplied by 256 (1<< 8) and divided by weight coefficients for Ipp16s datatype. The ippiQuantWeightBlockInv_DV_16s_C1I function has separate quantization and weighting tables that contain input arguments for the function.

See Example "Inverse Quantization Tables", Example "ippiQuantInv_DV_16s_C1I Usage", and Example "ippiQuantWeightBlockInv_DV_16s_C1I Usage" of ippiQuantInv_DV_16s_C1I and ippiQuantWeightBlockInv_DV_16s_C1I usage.

{

//-----------------------------------------------------------------------------
//Several necessary tables

#define _INTERNAL_CS1 0.980785  //cos(1*PI/16)
#define _INTERNAL_CS2 0.923880  //cos(2*PI/16)
#define _INTERNAL_CS3 0.831470  //cos(3*PI/16)
#define _INTERNAL_CS4 0.707107  //cos(4*PI/16)
#define _INTERNAL_CS5 0.555570  //cos(5*PI/16)
#define _INTERNAL_CS6 0.382683  //cos(6*PI/16)
#define _INTERNAL_CS7 0.195090  //cos(7*PI/16)

#define _W0 (1.0000001)
#define _W1 (_INTERNAL_CS4 / (4.0*  _INTERNAL_CS7*  _INTERNAL_CS2))
#define _W2 (_INTERNAL_CS4 / (2.0*  _INTERNAL_CS6))
#define _W3 (1.0 / (2.0*  _INTERNAL_CS5))
#define _W4 (7.0 / 8.0) 
#define _W5 (_INTERNAL_CS4 / _INTERNAL_CS3)
#define _W6 (_INTERNAL_CS4 / _INTERNAL_CS2)
#define _W7 (_INTERNAL_CS4 / _INTERNAL_CS1)

 tabl1[] = 
    {
        0,1,8,16,    9,2,3,10,
        17,24,32,25, 18,11,4,5,
        12,19,26,33, 40,48,41,34,
        27,20,13,6,  7,14,21,28,
        35,42,49,56, 57,50,43,36,
        29,22,15,23, 30,37,44,51,
        58,59,52,45, 38,31,39,46,
        53,60,61,54, 47,55,62,63
    };

    Ipp16s tabl2[] =
    {
        0,  32,  1, 33,  8, 40,  2, 34,
        9,  41, 16, 48, 24, 56, 17, 49,
        10, 42,  3, 35,  4, 36, 11, 43,
        18, 50, 25, 57, 26, 58, 19, 51,
        12, 44,  5, 37,  6, 38, 13, 45,
        20, 52, 27, 59, 28, 60, 21, 53,
        14, 46,  7, 39, 15, 47, 22, 54,
        29, 61, 30, 62, 23, 55, 31, 63       
    };

    static double TablW0[] =
    {

 (0.5/*2500076*/),(_W0*_W1/2),(_W0*_W2/2),(_W0*_W3/2),(_W0*_W4/2),(_W0*_W5/2),(_W0*_W6/2),(_W0*_W7/2),
 (_W1*_W0/2),(_W1*_W1/2),(_W1*_W2/2),(_W1*_W3/2),(_W1*_W4/2),(_W1*_W5/2),(_W1*_W6/2),(_W1*_W7/2),
 (_W2*_W0/2),(_W2*_W1/2),(_W2*_W2/2),(_W2*_W3/2),(_W2*_W4/2),(_W2*_W5/2),(_W2*_W6/2),(_W2*_W7/2),
 (_W3*_W0/2),(_W3*_W1/2),(_W3*_W2/2),(_W3*_W3/2),(_W3*_W4/2),(_W3*_W5/2),(_W3*_W6/2),(_W3*_W7/2),
 (_W4*_W0/2),(_W4*_W1/2),(_W4*_W2/2),(_W4*_W3/2),(_W4*_W4/2),(_W4*_W5/2),(_W4*_W6/2),(_W4*_W7/2),
 (_W5*_W0/2),(_W5*_W1/2),(_W5*_W2/2),(_W5*_W3/2),(_W5*_W4/2),(_W5*_W5/2),(_W5*_W6/2),(_W5*_W7/2),
 (_W6*_W0/2),(_W6*_W1/2),(_W6*_W2/2),(_W6*_W3/2),(_W6*_W4/2),(_W6*_W5/2),(_W6*_W6/2),(_W6*_W7/2),
 (_W7*_W0/2),(_W7*_W1/2),(_W7*_W2/2),(_W7*_W3/2),(_W7*_W4/2),(_W7*_W5/2),(_W7*_W6/2),(_W7*_W7/2)
    };

  static Ipp16s TablW0_Scale_ZigZag[] =
{
(Ipp16s)(8192.0/TablW0[0]), (Ipp16s)(8192.0/TablW0[1]), (Ipp16s)(8192.0/TablW0[8]), (Ipp16s)(8192.0/TablW0[16]),
(Ipp16s)(8192.0/TablW0[9]), (Ipp16s)(8192.0/TablW0[2]), (Ipp16s)(8192.0/TablW0[3]), (Ipp16s)(8192.0/TablW0[10]),
(Ipp16s)(8192.0/TablW0[17]),(Ipp16s)(8192.0/TablW0[24]),(Ipp16s)(8192.0/TablW0[32]),(Ipp16s)(8192.0/TablW0[25]),
(Ipp16s)(8192.0/TablW0[18]),(Ipp16s)(8192.0/TablW0[11]),(Ipp16s)(8192.0/TablW0[4]), (Ipp16s)(8192.0/TablW0[5]),
(Ipp16s)(8192.0/TablW0[12]),(Ipp16s)(8192.0/TablW0[19]),(Ipp16s)(8192.0/TablW0[26]),(Ipp16s)(8192.0/TablW0[33]),
(Ipp16s)(8192.0/TablW0[40]),(Ipp16s)(8192.0/TablW0[48]),(Ipp16s)(8192.0/TablW0[41]),(Ipp16s)(8192.0/TablW0[34]),
(Ipp16s)(8192.0/TablW0[27]),(Ipp16s)(8192.0/TablW0[20]),(Ipp16s)(8192.0/TablW0[13]),(Ipp16s)(8192.0/TablW0[6]),
(Ipp16s)(8192.0/TablW0[7]), (Ipp16s)(8192.0/TablW0[14]),(Ipp16s)(8192.0/TablW0[21]),(Ipp16s)(8192.0/TablW0[28]),
(Ipp16s)(8192.0/TablW0[35]),(Ipp16s)(8192.0/TablW0[42]),(Ipp16s)(8192.0/TablW0[49]),(Ipp16s)(8192.0/TablW0[56]),
(Ipp16s)(8192.0/TablW0[57]),(Ipp16s)(8192.0/TablW0[50]),(Ipp16s)(8192.0/TablW0[43]),(Ipp16s)(8192.0/TablW0[36]),
(Ipp16s)(8192.0/TablW0[29]),(Ipp16s)(8192.0/TablW0[22]),(Ipp16s)(8192.0/TablW0[15]),(Ipp16s)(8192.0/TablW0[23]),
(Ipp16s)(8192.0/TablW0[30]),(Ipp16s)(8192.0/TablW0[37]),(Ipp16s)(8192.0/TablW0[44]),(Ipp16s)(8192.0/TablW0[51]),
(Ipp16s)(8192.0/TablW0[58]),(Ipp16s)(8192.0/TablW0[59]),(Ipp16s)(8192.0/TablW0[52]),(Ipp16s)(8192.0/TablW0[45]),
(Ipp16s)(8192.0/TablW0[38]),(Ipp16s)(8192.0/TablW0[31]),(Ipp16s)(8192.0/TablW0[39]),(Ipp16s)(8192.0/TablW0[46]),
(Ipp16s)(8192.0/TablW0[53]),(Ipp16s)(8192.0/TablW0[60]),(Ipp16s)(8192.0/TablW0[61]),(Ipp16s)(8192.0/TablW0[54]),
(Ipp16s)(8192.0/TablW0[47]),(Ipp16s)(8192.0/TablW0[55]), (Ipp16s)(8192.0/TablW0[62]),(Ipp16s)(8192.0/TablW0[63])

};

    static double TablW1[] =
    {
(0.5/*2500076*/),(_W0*_W1/2),(_W0*_W2/2),(_W0*_W3/2),(_W0*_W4/2),(_W0*_W5/2),(_W0*_W6/2),(_W0*_W7/2),
(_W2*_W0/2),(_W2*_W1/2),(_W2*_W2/2),(_W2*_W3/2),(_W2*_W4/2),(_W2*_W5/2),(_W2*_W6/2),(_W2*_W7/2),
(_W4*_W0/2),(_W4*_W1/2),(_W4*_W2/2),(_W4*_W3/2),(_W4*_W4/2),(_W4*_W5/2),(_W4*_W6/2),(_W4*_W7/2),
(_W6*_W0/2),(_W6*_W1/2),(_W6*_W2/2),(_W6*_W3/2),(_W6*_W4/2),(_W6*_W5/2),(_W6*_W6/2),(_W6*_W7/2),
(_W0*_W0/2),(_W0*_W1/2),(_W0*_W2/2),(_W0*_W3/2),(_W0*_W4/2),(_W0*_W5/2),(_W0*_W6/2),(_W0*_W7/2),
(_W2*_W0/2),(_W2*_W1/2),(_W2*_W2/2),(_W2*_W3/2),(_W2*_W4/2),(_W2*_W5/2),(_W2*_W6/2),(_W2*_W7/2),
(_W4*_W0/2),(_W4*_W1/2),(_W4*_W2/2),(_W4*_W3/2),(_W4*_W4/2),(_W4*_W5/2),(_W4*_W6/2),(_W4*_W7/2),
(_W6*_W0/2),(_W6*_W1/2),(_W6*_W2/2),(_W6*_W3/2),(_W6*_W4/2),(_W6*_W5/2),(_W6*_W6/2),(_W6*_W7/2),
    };

    static Ipp16s TablW1_Scale_ZigZag[] =
{
(Ipp16s)(8192.0/TablW1[0]), (Ipp16s)(8192.0/TablW1[32]),(Ipp16s)(8192.0/TablW1[1]), (Ipp16s)(8192.0/TablW1[33]),
(Ipp16s)(8192.0/TablW1[8]), (Ipp16s)(8192.0/TablW1[40]),(Ipp16s)(8192.0/TablW1[2]), (Ipp16s)(8192.0/TablW1[34]),
(Ipp16s)(8192.0/TablW1[9]), (Ipp16s)(8192.0/TablW1[41]),(Ipp16s)(8192.0/TablW1[16]),(Ipp16s)(8192.0/TablW1[48]),
(Ipp16s)(8192.0/TablW1[24]),(Ipp16s)(8192.0/TablW1[56]),(Ipp16s)(8192.0/TablW1[17]),(Ipp16s)(8192.0/TablW1[49]),
(Ipp16s)(8192.0/TablW1[10]),(Ipp16s)(8192.0/TablW1[42]),(Ipp16s)(8192.0/TablW1[3]), (Ipp16s)(8192.0/TablW1[35]),
(Ipp16s)(8192.0/TablW1[4]), (Ipp16s)(8192.0/TablW1[36]),(Ipp16s)(8192.0/TablW1[11]),(Ipp16s)(8192.0/TablW1[43]),
(Ipp16s)(8192.0/TablW1[18]),(Ipp16s)(8192.0/TablW1[50]),(Ipp16s)(8192.0/TablW1[25]),(Ipp16s)(8192.0/TablW1[57]),
(Ipp16s)(8192.0/TablW1[26]),(Ipp16s)(8192.0/TablW1[58]),(Ipp16s)(8192.0/TablW1[19]),(Ipp16s)(8192.0/TablW1[51]),
(Ipp16s)(8192.0/TablW1[12]),(Ipp16s)(8192.0/TablW1[44]),(Ipp16s)(8192.0/TablW1[5]), (Ipp16s)(8192.0/TablW1[37]),
(Ipp16s)(8192.0/TablW1[6]), (Ipp16s)(8192.0/TablW1[38]),(Ipp16s)(8192.0/TablW1[13]),(Ipp16s)(8192.0/TablW1[45]),
(Ipp16s)(8192.0/TablW1[20]),(Ipp16s)(8192.0/TablW1[52]),(Ipp16s)(8192.0/TablW1[27]),(Ipp16s)(8192.0/TablW1[59]),
(Ipp16s)(8192.0/TablW1[28]),(Ipp16s)(8192.0/TablW1[60]),(Ipp16s)(8192.0/TablW1[21]),(Ipp16s)(8192.0/TablW1[53]),
(Ipp16s)(8192.0/TablW1[14]),(Ipp16s)(8192.0/TablW1[46]),(Ipp16s)(8192.0/TablW1[7]), (Ipp16s)(8192.0/TablW1[39]),
(Ipp16s)(8192.0/TablW1[15]),(Ipp16s)(8192.0/TablW1[47]),(Ipp16s)(8192.0/TablW1[22]),(Ipp16s)(8192.0/TablW1[54]),
(Ipp16s)(8192.0/TablW1[29]),(Ipp16s)(8192.0/TablW1[61]),(Ipp16s)(8192.0/TablW1[30]),(Ipp16s)(8192.0/TablW1[62]),
(Ipp16s)(8192.0/TablW1[23]),(Ipp16s)(8192.0/TablW1[55]),(Ipp16s)(8192.0/TablW1[31]),(Ipp16s)(8192.0/TablW1[63])
};
}

{
     	ippiHuffmanDecodeSegment_DV_8u16s((short* ) pDataBlock, ...);
      // get pointer to corresponding dequantize table
      // depends on qno & block quant class 
     	pQuantTable = (...);
     	if (0 == block_type)
    {
        for (Ipp32s iI = 0; iI < 64; iI++)
           		pQuantTable [iI] = pQuntTable [iI]* (Ipp16s)((double) (1 << 8) /
  TablW0[tabl1[iI]);

     	// do inverse and adaptive dequantization	
     	ippiQuantInv_DV_16s_C1I((short* ) pDataBlock), (short* ) pQuantTable);
     	// do iDCT
     	ippiDCT8x8Inv_16s_C1I((short* ) (pDataBlock));
    }

    else
    {
     	for (Ipp32s iI = 0; iI < 64; iI++)
	     pQuantTable [iI] = pQuantTable [iI]* (Ipp16s)(((double) (1 << 8)) /
  TablW1[tabl2[iI]);

	     // do inverse and adaptive dequantization
     	ippiQuantInv_DV_16s_C1I((short* ) pDataBlock), (short* ) pQuantTable);
     	// do iDCT
     	ippiDCT2x4x8Inv_16s_C1I((short* ) (pDataBlock) );
    }
};

{
    	ippiHuffmanDecodeSegment_DV_8u16s((short *) lpsBlocks,...);
    	// get pointer to corresponding dequantization table
    	// depends on qno & block quant class
    	pQauntTable = (...);

    	if (0 == block_type)
    	{
         		ippiQuantWeightBlockInv_DV_16s_C1I( (Ipp16s *) (pDataBlock),
                                               (Ipp16s *) pQuantTable,
                                               (Ipp16s *) TablW0_Scale_ZigZag );
   		// do iDCT
   		ippiDCT8x8Inv_16s_C1I((short *) (pDataBlock));
	 } 

	else
	 {
   		ippiQuantWeightBlockInv_DV_16s_C1I( (Ipp16s *) (pDataBlock),
                                         (Ipp16s *) pQuantTable,
                                         (Ipp16s *) TablW0_Scale_ZigZag );


		   // do iDCT
		   ippiDCT2x4x8Inv_16s_C1I((short *) (pDataBlock));
	 } 
};

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

Return Values