小白求助大佬，x265编码算法中数组名O[],EO[],EEO[],EEE[]等名字的意义或者来源

一段示例代码：
/** 函数功能 ：对残差块进行16x16DCT变换并对其转置

• \参数 block ：残差数据
• \参数 coeff ：存储行变换后的数据
• \参数 shift ：行变换移位个数

• \返回 ：null
  **/
  
  static void partialButterfly16(const int16_t* src, int16_t* dst, int shift, int line)
  
  {
  
  //功能：行变换 X*DCT’
  
  int j, k;
  
  int E[8], O[8];
  
  int EE[4], EO[4];
  
  int EEE[2], EEO[2];
  
  int add = 1 << (shift - 1);

  for (j = 0; j < line; j++)
  
  {
  
  /* E and O */
  
  for (k = 0; k < 8; k++)
  
  {
  
  E[k] = src[k] + src[15 - k];
  
  O[k] = src[k] - src[15 - k];
  
  }

  /* EE and EO */  
  for (k = 0; k < 4; k++)  
  {  
      EE[k] = E[k] + E[7 - k];  
      EO[k] = E[k] - E[7 - k];  
  }  
  
  /* EEE and EEO */  
  EEE[0] = EE[0] + EE[3];  
  EEO[0] = EE[0] - EE[3];  
  EEE[1] = EE[1] + EE[2];  
  EEO[1] = EE[1] - EE[2];  
  
  dst[0] = (int16_t)((g_t16[0][0] * EEE[0] + g_t16[0][1] * EEE[1] + add) >> shift);  
  dst[8 * line] = (int16_t)((g_t16[8][0] * EEE[0] + g_t16[8][1] * EEE[1] + add) >> shift);  
  dst[4 * line] = (int16_t)((g_t16[4][0] * EEO[0] + g_t16[4][1] * EEO[1] + add) >> shift);  
  dst[12 * line] = (int16_t)((g_t16[12][0] * EEO[0] + g_t16[12][1] * EEO[1] + add) >> shift);  
  
  for (k = 2; k < 16; k += 4)  
  {  
      dst[k * line] = (int16_t)((g_t16[k][0] * EO[0] + g_t16[k][1] * EO[1] + g_t16[k][2] * EO[2] +  
                                 g_t16[k][3] * EO[3] + add) >> shift);  
  }  
  
  for (k = 1; k < 16; k += 2)  
  {  
      dst[k * line] =  (int16_t)((g_t16[k][0] * O[0] + g_t16[k][1] * O[1] + g_t16[k][2] * O[2] + g_t16[k][3] * O[3] +  
                                  g_t16[k][4] * O[4] + g_t16[k][5] * O[5] + g_t16[k][6] * O[6] + g_t16[k][7] * O[7] +  
                                  add) >> shift);  
  }  
  
  src += 16;  
  dst++;  
  

  }
  
  }

如：
定义4字节有符号的临时数组：
O[16], EO[8], EE[4], EEEO[2], EEEE[2], EEE[8],E[16].
代码源http://blog.csdn.net/cabbage2008/article/details/50609275

http://blog.csdn.net/dragon_dy/article/details/52469678