xCalcHADs8x8_ISlice

轉載https://blog.csdn.net/king20168/article/details/52759843

// 函數功能是計算8×8塊的哈達瑪變換，並計算其SAD值，m2[8][8]存放最終的變換結果

Int xCalcHADs8x8_ISlice(Pel *piOrg, Int iStrideOrg)  
{  
Int k, i, j, jj;  
Int diff[64], m1[8][8], m2[8][8], m3[8][8], iSumHad = 0;  
  
//把8×8塊像素存放在一維數組中  
for( k = 0; k < 64; k += 8 )  
{  
diff[k+0] = piOrg[0] ;  
diff[k+1] = piOrg[1] ;  
diff[k+2] = piOrg[2] ;  
diff[k+3] = piOrg[3] ;  
diff[k+4] = piOrg[4] ;  
diff[k+5] = piOrg[5] ;  
diff[k+6] = piOrg[6] ;  
diff[k+7] = piOrg[7] ;  
  
piOrg += iStrideOrg; //指針指向下一行  
}  
  
//horizontal 水平變換，計算V=X×H，  
for (j=0; j < 8; j++)  
{  
jj = j << 3; //一次算8個，乘8換行  
m2[j][0] = diff[jj ] + diff[jj+4];  
m2[j][1] = diff[jj+1] + diff[jj+5];  
m2[j][2] = diff[jj+2] + diff[jj+6];  
m2[j][3] = diff[jj+3] + diff[jj+7];  
m2[j][4] = diff[jj ] - diff[jj+4];  
m2[j][5] = diff[jj+1] - diff[jj+5];  
m2[j][6] = diff[jj+2] - diff[jj+6];  
m2[j][7] = diff[jj+3] - diff[jj+7];  
  
m1[j][0] = m2[j][0] + m2[j][2];  
m1[j][1] = m2[j][1] + m2[j][3];  
m1[j][2] = m2[j][0] - m2[j][2];  
m1[j][3] = m2[j][1] - m2[j][3];  
m1[j][4] = m2[j][4] + m2[j][6];  
m1[j][5] = m2[j][5] + m2[j][7];  
m1[j][6] = m2[j][4] - m2[j][6];  
m1[j][7] = m2[j][5] - m2[j][7];  
  
m2[j][0] = m1[j][0] + m1[j][1];  
m2[j][1] = m1[j][0] - m1[j][1];  
m2[j][2] = m1[j][2] + m1[j][3];  
m2[j][3] = m1[j][2] - m1[j][3];  
m2[j][4] = m1[j][4] + m1[j][5];  
m2[j][5] = m1[j][4] - m1[j][5];  
m2[j][6] = m1[j][6] + m1[j][7];  
m2[j][7] = m1[j][6] - m1[j][7];  
}  
  
//vertical 垂直變換，計算H×V  
for (i=0; i < 8; i++)  
{  
m3[0][i] = m2[0][i] + m2[4][i];  
m3[1][i] = m2[1][i] + m2[5][i];  
m3[2][i] = m2[2][i] + m2[6][i];  
m3[3][i] = m2[3][i] + m2[7][i];  
m3[4][i] = m2[0][i] - m2[4][i];  
m3[5][i] = m2[1][i] - m2[5][i];  
m3[6][i] = m2[2][i] - m2[6][i];  
m3[7][i] = m2[3][i] - m2[7][i];  
  
m1[0][i] = m3[0][i] + m3[2][i];  
m1[1][i] = m3[1][i] + m3[3][i];  
m1[2][i] = m3[0][i] - m3[2][i];  
m1[3][i] = m3[1][i] - m3[3][i];  
m1[4][i] = m3[4][i] + m3[6][i];  
m1[5][i] = m3[5][i] + m3[7][i];  
m1[6][i] = m3[4][i] - m3[6][i];  
m1[7][i] = m3[5][i] - m3[7][i];  
  
m2[0][i] = m1[0][i] + m1[1][i];  
m2[1][i] = m1[0][i] - m1[1][i];  
m2[2][i] = m1[2][i] + m1[3][i];  
m2[3][i] = m1[2][i] - m1[3][i];  
m2[4][i] = m1[4][i] + m1[5][i];  
m2[5][i] = m1[4][i] - m1[5][i];  
m2[6][i] = m1[6][i] + m1[7][i];  
m2[7][i] = m1[6][i] - m1[7][i];  
}  
  
for (i = 0; i < 8; i++)  
{  
for (j = 0; j < 8; j++)  
{  
iSumHad += abs(m2[i][j]);  
}  
}  
iSumHad -= abs(m2[0][0]);  
iSumHad =(iSumHad+2)>>2; //除以係數4，並向上取整  
return(iSumHad);  
}