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📄 intra4x4_pred.c

📁 H.264基于baseline解码器的C++实现源码
💻 C
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  mb_pred[jpos3][ipos1] = (imgpel) ((P_E + P_G + 2*(P_F) + 2) >> 2);
  mb_pred[jpos2][ipos3] =
  mb_pred[jpos3][ipos2] = (imgpel) ((P_F + P_H + 2*(P_G) + 2) >> 2);
  mb_pred[jpos3][ipos3] = (imgpel) ((P_G + 3*(P_H) + 2) >> 2);

  return DECODING_OK;
}

/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 vertical right prediction mode
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *
 ***********************************************************************
 */
static inline int intra4x4_vert_right_pred(ImageParameters *img,  //!< image parameters 
                                           Macroblock *currMB,    //!< current macroblock
                                           ColorPlane pl,         //!< current image plane
                                           int ioff,              //!< pixel offset X within MB
                                           int joff)              //!< pixel offset Y within MB
{
  int i;
  imgpel PredPel[13];  // array of predictor pels
  imgpel **imgY = (pl) ? dec_picture->imgUV[pl - 1] : dec_picture->imgY;

  PixelPos pix_a[4];
  PixelPos pix_b, pix_d;

  int block_available_up;
  int block_available_left;
  int block_available_up_left;

  int jpos0 = joff, jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int ipos0 = ioff, ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  imgpel **mb_pred = img->mb_pred[pl];    

  for (i=0;i<4;i++)
  {
    getNeighbour(currMB, ioff -1 , joff +i , img->mb_size[IS_LUMA], &pix_a[i]);
  }

  getNeighbour(currMB, ioff    , joff -1 , img->mb_size[IS_LUMA], &pix_b);
  getNeighbour(currMB, ioff -1 , joff -1 , img->mb_size[IS_LUMA], &pix_d);

  if (active_pps->constrained_intra_pred_flag)
  {
    for (i=0, block_available_left=1; i<4;i++)
      block_available_left  &= pix_a[i].available ? img->intra_block[pix_a[i].mb_addr]: 0;
    block_available_up       = pix_b.available ? img->intra_block [pix_b.mb_addr] : 0;
    block_available_up_left  = pix_d.available ? img->intra_block [pix_d.mb_addr] : 0;
  }
  else
  {
    block_available_left     = pix_a[0].available;
    block_available_up       = pix_b.available;
    block_available_up_left  = pix_d.available;
  }

  if ((!block_available_up)||(!block_available_left)||(!block_available_up_left))
    printf ("warning: Intra_4x4_Vertical_Right prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

  // form predictor pels
  P_A = imgY[pix_b.pos_y][pix_b.pos_x + 0];
  P_B = imgY[pix_b.pos_y][pix_b.pos_x + 1];
  P_C = imgY[pix_b.pos_y][pix_b.pos_x + 2];
  P_D = imgY[pix_b.pos_y][pix_b.pos_x + 3];

  P_I = imgY[pix_a[0].pos_y][pix_a[0].pos_x];
  P_J = imgY[pix_a[1].pos_y][pix_a[1].pos_x];
  P_K = imgY[pix_a[2].pos_y][pix_a[2].pos_x];
  P_L = imgY[pix_a[3].pos_y][pix_a[3].pos_x];

  P_X = imgY[pix_d.pos_y][pix_d.pos_x];

  mb_pred[jpos0][ipos0] =
  mb_pred[jpos2][ipos1] = (imgpel) ((P_X + P_A + 1) >> 1);
  mb_pred[jpos0][ipos1] =
  mb_pred[jpos2][ipos2] = (imgpel) ((P_A + P_B + 1) >> 1);
  mb_pred[jpos0][ipos2] =
  mb_pred[jpos2][ipos3] = (imgpel) ((P_B + P_C + 1) >> 1);
  mb_pred[jpos0][ipos3] = (imgpel) ((P_C + P_D + 1) >> 1);
  mb_pred[jpos1][ipos0] =
  mb_pred[jpos3][ipos1] = (imgpel) ((P_I + 2*P_X + P_A + 2) >> 2);
  mb_pred[jpos1][ipos1] =
  mb_pred[jpos3][ipos2] = (imgpel) ((P_X + 2*P_A + P_B + 2) >> 2);
  mb_pred[jpos1][ipos2] =
  mb_pred[jpos3][ipos3] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
  mb_pred[jpos1][ipos3] = (imgpel) ((P_B + 2*P_C + P_D + 2) >> 2);
  mb_pred[jpos2][ipos0] = (imgpel) ((P_X + 2*P_I + P_J + 2) >> 2);
  mb_pred[jpos3][ipos0] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);

  return DECODING_OK;
}


/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 vertical left prediction mode
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *
 ***********************************************************************
 */
static inline int intra4x4_vert_left_pred(ImageParameters *img,  //!< image parameters 
                                          Macroblock *currMB,    //!< current macroblock
                                          ColorPlane pl,         //!< current image plane
                                          int ioff,              //!< pixel offset X within MB
                                          int joff)              //!< pixel offset Y within MB
{
  imgpel PredPel[13];  // array of predictor pels  
  imgpel **imgY = (pl) ? dec_picture->imgUV[pl - 1] : dec_picture->imgY;

  PixelPos pix_b, pix_c;

  int block_available_up;
  int block_available_up_right;

  int jpos0 = joff, jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int ipos0 = ioff, ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  imgpel **mb_pred = img->mb_pred[pl];    

  getNeighbour(currMB, ioff    , joff -1 , img->mb_size[IS_LUMA], &pix_b);
  getNeighbour(currMB, ioff +4 , joff -1 , img->mb_size[IS_LUMA], &pix_c);

  pix_c.available = pix_c.available && !((ioff==4) && ((joff==4)||(joff==12)));
  
  if (active_pps->constrained_intra_pred_flag)
  {
    block_available_up       = pix_b.available ? img->intra_block [pix_b.mb_addr] : 0;
    block_available_up_right = pix_c.available ? img->intra_block [pix_c.mb_addr] : 0;
  }
  else
  {
    block_available_up       = pix_b.available;
    block_available_up_right = pix_c.available;
  }


  if (!block_available_up)
    printf ("warning: Intra_4x4_Vertical_Left prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

  // form predictor pels
  P_A = imgY[pix_b.pos_y][pix_b.pos_x + 0];
  P_B = imgY[pix_b.pos_y][pix_b.pos_x + 1];
  P_C = imgY[pix_b.pos_y][pix_b.pos_x + 2];
  P_D = imgY[pix_b.pos_y][pix_b.pos_x + 3];

  if (block_available_up_right)
  {
    P_E = imgY[pix_c.pos_y][pix_c.pos_x + 0];
    P_F = imgY[pix_c.pos_y][pix_c.pos_x + 1];
    P_G = imgY[pix_c.pos_y][pix_c.pos_x + 2];
    P_H = imgY[pix_c.pos_y][pix_c.pos_x + 3];
  }
  else
  {
    P_E = P_F = P_G = P_H = P_D;
  }

  mb_pred[jpos0][ipos0] = (imgpel) ((P_A + P_B + 1) >> 1);
  mb_pred[jpos0][ipos1] =
  mb_pred[jpos2][ipos0] = (imgpel) ((P_B + P_C + 1) >> 1);
  mb_pred[jpos0][ipos2] =
  mb_pred[jpos2][ipos1] = (imgpel) ((P_C + P_D + 1) >> 1);
  mb_pred[jpos0][ipos3] =
  mb_pred[jpos2][ipos2] = (imgpel) ((P_D + P_E + 1) >> 1);
  mb_pred[jpos2][ipos3] = (imgpel) ((P_E + P_F + 1) >> 1);
  mb_pred[jpos1][ipos0] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
  mb_pred[jpos1][ipos1] =
  mb_pred[jpos3][ipos0] = (imgpel) ((P_B + 2*P_C + P_D + 2) >> 2);
  mb_pred[jpos1][ipos2] =
  mb_pred[jpos3][ipos1] = (imgpel) ((P_C + 2*P_D + P_E + 2) >> 2);
  mb_pred[jpos1][ipos3] =
  mb_pred[jpos3][ipos2] = (imgpel) ((P_D + 2*P_E + P_F + 2) >> 2);
  mb_pred[jpos3][ipos3] = (imgpel) ((P_E + 2*P_F + P_G + 2) >> 2);

  return DECODING_OK;
}

/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 horizontal up prediction mode
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *
 ***********************************************************************
 */
static inline int intra4x4_hor_up_pred(ImageParameters *img,  //!< image parameters 
                                       Macroblock *currMB,    //!< current macroblock
                                       ColorPlane pl,         //!< current image plane
                                       int ioff,              //!< pixel offset X within MB
                                       int joff)              //!< pixel offset Y within MB
{
  int i;
  imgpel PredPel[13];  // array of predictor pels
  imgpel **imgY = (pl) ? dec_picture->imgUV[pl - 1] : dec_picture->imgY;

  PixelPos pix_a[4];

  int block_available_left;

  int jpos0 = joff, jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int ipos0 = ioff, ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  imgpel **mb_pred = img->mb_pred[pl];    

  for (i=0;i<4;i++)
  {
    getNeighbour(currMB, ioff -1 , joff +i , img->mb_size[IS_LUMA], &pix_a[i]);
  }

  if (active_pps->constrained_intra_pred_flag)
  {
    for (i=0, block_available_left=1; i<4;i++)
      block_available_left  &= pix_a[i].available ? img->intra_block[pix_a[i].mb_addr]: 0;
  }
  else
  {
    block_available_left     = pix_a[0].available;
  }

  if (!block_available_left)
    printf ("warning: Intra_4x4_Horizontal_Up prediction mode not allowed at mb %d\n",(int) img->current_mb_nr);

  // form predictor pels
  P_I = imgY[pix_a[0].pos_y][pix_a[0].pos_x];
  P_J = imgY[pix_a[1].pos_y][pix_a[1].pos_x];
  P_K = imgY[pix_a[2].pos_y][pix_a[2].pos_x];
  P_L = imgY[pix_a[3].pos_y][pix_a[3].pos_x];

  mb_pred[jpos0][ipos0] = (imgpel) ((P_I + P_J + 1) >> 1);
  mb_pred[jpos0][ipos1] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);
  mb_pred[jpos0][ipos2] =
  mb_pred[jpos1][ipos0] = (imgpel) ((P_J + P_K + 1) >> 1);
  mb_pred[jpos0][ipos3] =
  mb_pred[jpos1][ipos1] = (imgpel) ((P_J + 2*P_K + P_L + 2) >> 2);
  mb_pred[jpos1][ipos2] =
  mb_pred[jpos2][ipos0] = (imgpel) ((P_K + P_L + 1) >> 1);
  mb_pred[jpos1][ipos3] =
  mb_pred[jpos2][ipos1] = (imgpel) ((P_K + 2*P_L + P_L + 2) >> 2);
  mb_pred[jpos2][ipos3] =
  mb_pred[jpos3][ipos1] =
  mb_pred[jpos3][ipos0] =
  mb_pred[jpos2][ipos2] =
  mb_pred[jpos3][ipos2] =
  mb_pred[jpos3][ipos3] = (imgpel) P_L;

  return DECODING_OK;
}

/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 horizontal down prediction mode
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *
 ***********************************************************************
 */
static inline int intra4x4_hor_down_pred(ImageParameters *img,  //!< image parameters 
                                         Macroblock *currMB,    //!< current macroblock
                                         ColorPlane pl,         //!< current image plane
                                         int ioff,              //!< pixel offset X within MB
                                         int joff)              //!< pixel offset Y within MB
{
  int i;
  imgpel PredPel[13];  // array of predictor pels
  imgpel **imgY = (pl) ? dec_picture->imgUV[pl - 1] : dec_picture->imgY;

  PixelPos pix_a[4];
  PixelPos pix_b, pix_d;

  int block_available_up;
  int block_available_left;
  int block_available_up_left;

  int jpos0 = joff, jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int ipos0 = ioff, ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  imgpel **mb_pred = img->mb_pred[pl];    
  
  for (i=0;i<4;i++)
  {
    getNeighbour(currMB, ioff -1 , joff +i , img->mb_size[IS_LUMA], &pix_a[i]);
  }

  getNeighbour(currMB, ioff    , joff -1 , img->mb_size[IS_LUMA], &pix_b);
  getNeighbour(currMB, ioff -1 , joff -1 , img->mb_size[IS_LUMA], &pix_d);

  if (active_pps->constrained_intra_pred_flag)
  {
    for (i=0, block_available_left=1; i<4;i++)
      block_available_left  &= pix_a[i].available ? img->intra_block[pix_a[i].mb_addr]: 0;
    block_available_up       = pix_b.available ? img->intra_block [pix_b.mb_addr] : 0;
    block_available_up_left  = pix_d.available ? img->intra_block [pix_d.mb_addr] : 0;
  }
  else
  {
    block_available_left     = pix_a[0].available;
    block_available_up       = pix_b.available;
    block_available_up_left  = pix_d.available;
  }

  if ((!block_available_up)||(!block_available_left)||(!block_available_up_left))
    printf ("warning: Intra_4x4_Horizontal_Down prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

  // form predictor pels
  P_A = imgY[pix_b.pos_y][pix_b.pos_x + 0];
  P_B = imgY[pix_b.pos_y][pix_b.pos_x + 1];
  P_C = imgY[pix_b.pos_y][pix_b.pos_x + 2];
  P_D = imgY[pix_b.pos_y][pix_b.pos_x + 3];

  P_I = imgY[pix_a[0].pos_y][pix_a[0].pos_x];
  P_J = imgY[pix_a[1].pos_y][pix_a[1].pos_x];
  P_K = imgY[pix_a[2].pos_y][pix_a[2].pos_x];
  P_L = imgY[pix_a[3].pos_y][pix_a[3].pos_x];

  P_X = imgY[pix_d.pos_y][pix_d.pos_x];

  mb_pred[jpos0][ipos0] =
  mb_pred[jpos1][ipos2] = (imgpel) ((P_X + P_I + 1) >> 1);
  mb_pred[jpos0][ipos1] =
  mb_pred[jpos1][ipos3] = (imgpel) ((P_I + 2*P_X + P_A + 2) >> 2);
  mb_pred[jpos0][ipos2] = (imgpel) ((P_X + 2*P_A + P_B + 2) >> 2);
  mb_pred[jpos0][ipos3] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
  mb_pred[jpos1][ipos0] =
  mb_pred[jpos2][ipos2] = (imgpel) ((P_I + P_J + 1) >> 1);
  mb_pred[jpos1][ipos1] =
  mb_pred[jpos2][ipos3] = (imgpel) ((P_X + 2*P_I + P_J + 2) >> 2);
  mb_pred[jpos2][ipos0] =
  mb_pred[jpos3][ipos2] = (imgpel) ((P_J + P_K + 1) >> 1);
  mb_pred[jpos2][ipos1] =
  mb_pred[jpos3][ipos3] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);
  mb_pred[jpos3][ipos0] = (imgpel) ((P_K + P_L + 1) >> 1);
  mb_pred[jpos3][ipos1] = (imgpel) ((P_J + 2*P_K + P_L + 2) >> 2);

  return DECODING_OK;
}


/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 intra prediction blocks 
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *    SEARCH_SYNC   search next sync element as errors while decoding occured
 ***********************************************************************
 */
int intrapred(ImageParameters *img,  //!< image parameters 
              Macroblock *currMB,    //!< current macroblock
              ColorPlane pl,         //!< current image plane
              int ioff,              //!< pixel offset X within MB
              int joff,              //!< pixel offset Y within MB
              int img_block_x,       //!< location of block X, multiples of 4
              int img_block_y)       //!< location of block Y, multiples of 4
{
  byte predmode = img->ipredmode[img_block_y][img_block_x];
  ipmode_DPCM = predmode; //For residual DPCM

  switch (predmode)
  {
  case DC_PRED:
    return (intra4x4_dc_pred(img, currMB, pl, ioff, joff));
    break;
  case VERT_PRED:
    return (intra4x4_vert_pred(img, currMB, pl, ioff, joff));
    break;
  case HOR_PRED:
    return (intra4x4_hor_pred(img, currMB, pl, ioff, joff));
    break;
  case DIAG_DOWN_RIGHT_PRED:
    return (intra4x4_diag_down_right_pred(img, currMB, pl, ioff, joff));
    break;
  case DIAG_DOWN_LEFT_PRED:
    return (intra4x4_diag_down_left_pred(img, currMB, pl, ioff, joff));
    break;
  case VERT_RIGHT_PRED:
    return (intra4x4_vert_right_pred(img, currMB, pl, ioff, joff));
    break;
  case VERT_LEFT_PRED:
    return (intra4x4_vert_left_pred(img, currMB, pl, ioff, joff));
    break;
  case HOR_UP_PRED:
    return (intra4x4_hor_up_pred(img, currMB, pl, ioff, joff));
    break;
  case HOR_DOWN_PRED:  
    return (intra4x4_hor_down_pred(img, currMB, pl, ioff, joff));
  default:
    printf("Error: illegal intra_4x4 prediction mode: %d\n", (int) predmode);
    return SEARCH_SYNC;
    break;
  }

  return DECODING_OK;  
}

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