mb_access.c

压缩JM12.3d的完整的全部C语言的代码文档,用于嵌入式系统的压缩编解码

          if ((curr_mb_nr & 0x01) == 0)
          {
            // top
            pix->mb_addr   = currMb->mbAddrA;
            pix->available = currMb->mbAvailA;
            if (currMb->mbAvailA)
            {
              if(!img->mb_data[currMb->mbAddrA].mb_field)
              {
                 yM = yN;
              }
              else
              {
                if ((yN & 0x01) == 0)
                {
                   yM = yN>> 1;
                }
                else
                {
                  (pix->mb_addr)++;
                   yM = yN>> 1;
                }
              }
            }
          }
          else
          {
            // bottom
            pix->mb_addr   = currMb->mbAddrA;
            pix->available = currMb->mbAvailA;
            if (currMb->mbAvailA)
            {
              if(!img->mb_data[currMb->mbAddrA].mb_field)
              {
                (pix->mb_addr)++;
                 yM = yN;
              }
              else
              {
                if ((yN & 0x01) == 0)
                {
                   yM = (yN + maxH) >> 1;
                }
                else
                {
                  (pix->mb_addr)++;
                   yM = (yN + maxH) >> 1;
                }
              }
            }
          }
        }
        else
        {
          // field
          if ((curr_mb_nr & 0x01) == 0)
          {
            // top
            pix->mb_addr  = currMb->mbAddrA;
            pix->available = currMb->mbAvailA;
            if (currMb->mbAvailA)
            {
              if(!img->mb_data[currMb->mbAddrA].mb_field)
              {
                if (yN < (maxH >> 1))
                {
                   yM = yN << 1;
                }
                else
                {
                  (pix->mb_addr)++;
                   yM = (yN << 1 ) - maxH;
                }
              }
              else
              {
                 yM = yN;
              }
            }
          }
          else
          {
            // bottom
            pix->mb_addr  = currMb->mbAddrA;
            pix->available = currMb->mbAvailA;
            if (currMb->mbAvailA)
            {
              if(!img->mb_data[currMb->mbAddrA].mb_field)
              {
                if (yN < (maxH >> 1))
                {
                  yM = (yN << 1) + 1;
                }
                else
                {
                  (pix->mb_addr)++;
                   yM = (yN << 1 ) + 1 - maxH;
                }
              }
              else
              {
                (pix->mb_addr)++;
                 yM = yN;
              }
            }
          }
        }
      }
    }
  }
  else
  { // xN >= 0
    if (xN >= 0 && xN < maxW)
    {
      if (yN<0)
      {
        if (!currMb->mb_field)
        {
          //frame
          if ((curr_mb_nr & 0x01) == 0)
          {
            //top
            pix->mb_addr  = currMb->mbAddrB;
            // for the deblocker if the current MB is a frame and the one above is a field
            // then the neighbor is the top MB of the pair
            if (currMb->mbAvailB)
            {
              if (!(img->DeblockCall == 1 && (img->mb_data[currMb->mbAddrB]).mb_field))
                pix->mb_addr  += 1;
            }

            pix->available = currMb->mbAvailB;
            yM = yN;
          }
          else
          {
            // bottom
            pix->mb_addr   = curr_mb_nr - 1;
            pix->available = TRUE;
            yM = yN;
          }
        }
        else
        {
          // field
          if ((curr_mb_nr & 0x01) == 0)
          {
            // top
            pix->mb_addr   = currMb->mbAddrB;
            pix->available = currMb->mbAvailB;
            if (currMb->mbAvailB)
            {
              if(!img->mb_data[currMb->mbAddrB].mb_field)
              {
                (pix->mb_addr)++;
                 yM = 2* yN;
              }
              else
              {
                 yM = yN;
              }
            }
          }
          else
          {
            // bottom
            pix->mb_addr   = currMb->mbAddrB + 1;
            pix->available = currMb->mbAvailB;
            yM = yN;
          }
        }
      }
      else
      {
        // yN >=0
        // for the deblocker if this is the extra edge then do this special stuff
        if (yN == 0 && img->DeblockCall == 2)
        {
          pix->mb_addr  = currMb->mbAddrB + 1;
          pix->available = TRUE;
          yM = yN - 1;
        }

        else if ((yN >= 0) && (yN <maxH))
        {
          pix->mb_addr   = curr_mb_nr;
          pix->available = TRUE;
          yM = yN;
        }
      }
    }
    else
    { // xN >= maxW
      if(yN < 0)
      {
        if (!currMb->mb_field)
        {
          // frame
          if ((curr_mb_nr & 0x01) == 0)
          {
            // top
            pix->mb_addr  = currMb->mbAddrC + 1;
            pix->available = currMb->mbAvailC;
            yM = yN;
          }
          else
          {
            // bottom
            pix->available = FALSE;
          }
        }
        else
        {
          // field
          if ((curr_mb_nr & 0x01) == 0)
          {
            // top
            pix->mb_addr   = currMb->mbAddrC;
            pix->available = currMb->mbAvailC;
            if (currMb->mbAvailC)
            {
              if(!img->mb_data[currMb->mbAddrC].mb_field)
              {
                (pix->mb_addr)++;
                 yM = 2* yN;
              }
              else
              {
                yM = yN;
              }
            }
          }
          else
          {
            // bottom
            pix->mb_addr   = currMb->mbAddrC + 1;
            pix->available = currMb->mbAvailC;
            yM = yN;
          }
        }
      }
    }
  }
  if (pix->available || img->DeblockCall)
  {
    pix->x = xN & (maxW - 1);
    pix->y = yM & (maxH - 1);
    get_mb_pos(pix->mb_addr, &(pix->pos_x), &(pix->pos_y), is_chroma);
    pix->pos_x += pix->x;
    pix->pos_y += pix->y;
  }
}

/*!
 ************************************************************************
 * \brief
 *    get neighboring 4x4 luma block
 * \param curr_mb_nr
 *   current macroblock number (decoding order)
 * \param block_x
 *    input x block position
 * \param block_y
 *    input y block position
 * \param pix
 *    returns position informations
 ************************************************************************
 */
void getLuma4x4Neighbour (int curr_mb_nr, int block_x, int block_y, PixelPos *pix)
{
  getNeighbour(curr_mb_nr, block_x, block_y, IS_LUMA, pix);

  if (pix->available)
  {
    pix->x >>= 2;
    pix->y >>= 2;
    pix->pos_x >>= 2;
    pix->pos_y >>= 2;
  }
}


/*!
 ************************************************************************
 * \brief
 *    get neighboring 4x4 chroma block
 * \param curr_mb_nr
 *   current macroblock number (decoding order)
 * \param block_x
 *    input x block position
 * \param block_y
 *    input y block position
 * \param pix
 *    returns position informations
 ************************************************************************
 */
void getChroma4x4Neighbour (int curr_mb_nr, int block_x, int block_y, PixelPos *pix)
{
  getNeighbour(curr_mb_nr, block_x, block_y, IS_CHROMA, pix);

  if (pix->available)
  {
    pix->x >>= 2;
    pix->y >>= 2;
    pix->pos_x >>= 2;
    pix->pos_y >>= 2;
  }
}