block.c

包含了从MPEG4的视频解码到H.264的视频编码部分的源代码

    break;

  case  VERT_RIGHT_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    img->mpr[0+ioff][0+joff] = 
    img->mpr[1+ioff][2+joff] = (P_X + P_A + 1) / 2;
    img->mpr[1+ioff][0+joff] = 
    img->mpr[2+ioff][2+joff] = (P_A + P_B + 1) / 2;
    img->mpr[2+ioff][0+joff] = 
    img->mpr[3+ioff][2+joff] = (P_B + P_C + 1) / 2;
    img->mpr[3+ioff][0+joff] = (P_C + P_D + 1) / 2;
    img->mpr[0+ioff][1+joff] = 
    img->mpr[1+ioff][3+joff] = (P_I + 2*P_X + P_A + 2) / 4;
    img->mpr[1+ioff][1+joff] = 
    img->mpr[2+ioff][3+joff] = (P_X + 2*P_A + P_B + 2) / 4;
    img->mpr[2+ioff][1+joff] = 
    img->mpr[3+ioff][3+joff] = (P_A + 2*P_B + P_C + 2) / 4;
    img->mpr[3+ioff][1+joff] = (P_B + 2*P_C + P_D + 2) / 4;
    img->mpr[0+ioff][2+joff] = (P_X + 2*P_I + P_J + 2) / 4;
    img->mpr[0+ioff][3+joff] = (P_I + 2*P_J + P_K + 2) / 4;
    break;

  case  VERT_LEFT_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    img->mpr[0+ioff][0+joff] = (P_A + P_B + 1) / 2;
    img->mpr[1+ioff][0+joff] = 
    img->mpr[0+ioff][2+joff] = (P_B + P_C + 1) / 2;
    img->mpr[2+ioff][0+joff] = 
    img->mpr[1+ioff][2+joff] = (P_C + P_D + 1) / 2;
    img->mpr[3+ioff][0+joff] = 
    img->mpr[2+ioff][2+joff] = (P_D + P_E + 1) / 2;
    img->mpr[3+ioff][2+joff] = (P_E + P_F + 1) / 2;
    img->mpr[0+ioff][1+joff] = (P_A + 2*P_B + P_C + 2) / 4;
    img->mpr[1+ioff][1+joff] = 
    img->mpr[0+ioff][3+joff] = (P_B + 2*P_C + P_D + 2) / 4;
    img->mpr[2+ioff][1+joff] = 
    img->mpr[1+ioff][3+joff] = (P_C + 2*P_D + P_E + 2) / 4;
    img->mpr[3+ioff][1+joff] = 
    img->mpr[2+ioff][3+joff] = (P_D + 2*P_E + P_F + 2) / 4;
    img->mpr[3+ioff][3+joff] = (P_E + 2*P_F + P_G + 2) / 4;
    break;

  case  HOR_UP_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    img->mpr[0+ioff][0+joff] = (P_I + P_J + 1) / 2;
    img->mpr[1+ioff][0+joff] = (P_I + 2*P_J + P_K + 2) / 4;
    img->mpr[2+ioff][0+joff] = 
    img->mpr[0+ioff][1+joff] = (P_J + P_K + 1) / 2;
    img->mpr[3+ioff][0+joff] = 
    img->mpr[1+ioff][1+joff] = (P_J + 2*P_K + P_L + 2) / 4;
    img->mpr[2+ioff][1+joff] = 
    img->mpr[0+ioff][2+joff] = (P_K + P_L + 1) / 2;
    img->mpr[3+ioff][1+joff] = 
    img->mpr[1+ioff][2+joff] = (P_K + 2*P_L + P_L + 2) / 4;
    img->mpr[3+ioff][2+joff] = 
    img->mpr[1+ioff][3+joff] = 
    img->mpr[0+ioff][3+joff] = 
    img->mpr[2+ioff][2+joff] = 
    img->mpr[2+ioff][3+joff] = 
    img->mpr[3+ioff][3+joff] = P_L;
    break;

  case  HOR_DOWN_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    img->mpr[0+ioff][0+joff] = 
    img->mpr[2+ioff][1+joff] = (P_X + P_I + 1) / 2;
    img->mpr[1+ioff][0+joff] = 
    img->mpr[3+ioff][1+joff] = (P_I + 2*P_X + P_A + 2) / 4;
    img->mpr[2+ioff][0+joff] = (P_X + 2*P_A + P_B + 2) / 4;
    img->mpr[3+ioff][0+joff] = (P_A + 2*P_B + P_C + 2) / 4;
    img->mpr[0+ioff][1+joff] = 
    img->mpr[2+ioff][2+joff] = (P_I + P_J + 1) / 2;
    img->mpr[1+ioff][1+joff] = 
    img->mpr[3+ioff][2+joff] = (P_X + 2*P_I + P_J + 2) / 4;
    img->mpr[0+ioff][2+joff] = 
    img->mpr[2+ioff][3+joff] = (P_J + P_K + 1) / 2;
    img->mpr[1+ioff][2+joff] = 
    img->mpr[3+ioff][3+joff] = (P_I + 2*P_J + P_K + 2) / 4;
    img->mpr[0+ioff][3+joff] = (P_K + P_L + 1) / 2;
    img->mpr[1+ioff][3+joff] = (P_J + 2*P_K + P_L + 2) / 4;
    break;

  default:
    printf("Error: illegal prediction mode input: %d\n",predmode);
    return SEARCH_SYNC;
    break;
  }

  return DECODING_OK;
}


/*!
 ***********************************************************************
 * \return
 *    best SAD
 ***********************************************************************
 */
int intrapred_luma_16x16(struct img_par *img, //!< image parameters
                         int predmode)        //!< prediction mode
{
  int s0=0,s1,s2;

  int i,j;

  int ih,iv;
  int ib,ic,iaa;

  int mb_width = img->width/16;
  //int mb_nr_frame = img->mb_y*mb_width+img->mb_x;
  int mb_nr = img->map_mb_nr;// GB img->current_mb_nr;
  int mb_available_up = (img->mb_y == 0) ? 0 : (img->mb_data[mb_nr].slice_nr == img->mb_data[mb_nr-mb_width].slice_nr);
  int mb_available_left = (img->mb_x == 0) ? 0 : (img->mb_data[mb_nr].slice_nr == img->mb_data[mb_nr-1].slice_nr);
  int field_y = img->pix_y;   // For MB level frame/field coding
  if (img->mb_field)
  {
    field_y /= 2;
    mb_available_up = (img->mb_y/2 == 0) ? 0 : 1;

  if (img->current_mb_nr%2) // bottom field
  {
    field_y -= BLOCK_SIZE*2;
      mb_available_up = ((img->mb_y-1)/2 == 0) ? 0 : 1;
  }
  }

  if(img->constrained_intra_pred_flag)
  {
    if (mb_available_up   && (img->intra_block[mb_nr-mb_width][2]==0 || img->intra_block[mb_nr-mb_width][3]==0))
      mb_available_up   = 0;
    if (mb_available_left && (img->intra_block[mb_nr-       1][1]==0 || img->intra_block[mb_nr       -1][3]==0))
      mb_available_left = 0;
  }

  s1=s2=0;

  switch (predmode)
  {
  case VERT_PRED_16:                       // vertical prediction from block above
    for(j=0;j<MB_BLOCK_SIZE;j++)
      for(i=0;i<MB_BLOCK_SIZE;i++)
        img->mpr[i][j]=imgY[field_y-1][img->pix_x+i];// store predicted 16x16 block
    break;

  case HOR_PRED_16:                        // horisontal prediction from left block
    for(j=0;j<MB_BLOCK_SIZE;j++)
      for(i=0;i<MB_BLOCK_SIZE;i++)
        img->mpr[i][j]=imgY[field_y+j][img->pix_x-1]; // store predicted 16x16 block
    break;

  case DC_PRED_16:                         // DC prediction
    s1=s2=0;
    for (i=0; i < MB_BLOCK_SIZE; i++)
    {
      if (mb_available_up)
        s1 += imgY[field_y-1][img->pix_x+i];    // sum hor pix
      if (mb_available_left)
        s2 += imgY[field_y+i][img->pix_x-1];    // sum vert pix
    }
    if (mb_available_up && mb_available_left)
      s0=(s1+s2+16)/(2*MB_BLOCK_SIZE);       // no edge
    if (!mb_available_up && mb_available_left)
      s0=(s2+8)/MB_BLOCK_SIZE;              // upper edge
    if (mb_available_up && !mb_available_left)
      s0=(s1+8)/MB_BLOCK_SIZE;              // left edge
    if (!mb_available_up && !mb_available_left)
      s0=128;                            // top left corner, nothing to predict from
    for(i=0;i<MB_BLOCK_SIZE;i++)
      for(j=0;j<MB_BLOCK_SIZE;j++)
      {
        img->mpr[i][j]=s0;
      }
    break;
  case PLANE_16:// 16 bit integer plan pred
    ih=0;
    iv=0;
    for (i=1;i<9;i++)
    {
      ih += i*(imgY[field_y-1][img->pix_x+7+i] - imgY[field_y-1][img->pix_x+7-i]);
      iv += i*(imgY[field_y+7+i][img->pix_x-1] - imgY[field_y+7-i][img->pix_x-1]);
    }
    ib=(5*ih+32)>>6;
    ic=(5*iv+32)>>6;

    iaa=16*(imgY[field_y-1][img->pix_x+15]+imgY[field_y+15][img->pix_x-1]);
    for (j=0;j< MB_BLOCK_SIZE;j++)
    {
      for (i=0;i< MB_BLOCK_SIZE;i++)
      {
        img->mpr[i][j]=max(0,min((iaa+(i-7)*ib +(j-7)*ic + 16)/32,255));
      }
    }// store plane prediction
    break;

  default:
    {                                    // indication of fault in bitstream,exit
      printf("Error: illegal prediction mode input: %d\n",predmode);
      return SEARCH_SYNC;
    }
  }

  return DECODING_OK;
}

/*!
 ***********************************************************************
 * \brief
 *    Inverse 4x4 transformation, transforms cof to m7
 ***********************************************************************
 */
void itrans(struct img_par *img, //!< image parameters
            int ioff,            //!< index to 4x4 block
            int joff,            //!<
            int i0,              //!<
            int j0)              //!<
{
  int i,j,i1,j1;
  int m5[4];
  int m6[4];

  // horizontal
  for (j=0;j<BLOCK_SIZE;j++)
  {
    for (i=0;i<BLOCK_SIZE;i++)
    {
      m5[i]=img->cof[i0][j0][i][j];
    }
    m6[0]=(m5[0]+m5[2]);
    m6[1]=(m5[0]-m5[2]);
    m6[2]=(m5[1]>>1)-m5[3];
    m6[3]=m5[1]+(m5[3]>>1);

    for (i=0;i<2;i++)
    {
      i1=3-i;
      img->m7[i][j]=m6[i]+m6[i1];
      img->m7[i1][j]=m6[i]-m6[i1];
    }
  }
  // vertical
  for (i=0;i<BLOCK_SIZE;i++)
  {
    for (j=0;j<BLOCK_SIZE;j++)
      m5[j]=img->m7[i][j];

    m6[0]=(m5[0]+m5[2]);
    m6[1]=(m5[0]-m5[2]);
    m6[2]=(m5[1]>>1)-m5[3];
    m6[3]=m5[1]+(m5[3]>>1);

    for (j=0;j<2;j++)
    {
      j1=3-j;
      img->m7[i][j] =mmax(0,mmin(255,(m6[j]+m6[j1]+(img->mpr[i+ioff][j+joff] <<DQ_BITS)+DQ_ROUND)>>DQ_BITS));
      img->m7[i][j1]=mmax(0,mmin(255,(m6[j]-m6[j1]+(img->mpr[i+ioff][j1+joff]<<DQ_BITS)+DQ_ROUND)>>DQ_BITS));
    }
  }

}


/*!
 ***********************************************************************
 * \brief
 *    invers  transform
 ***********************************************************************
 */
void itrans_2(
   struct img_par *img) //!< image parameters
{
  int i,j,i1,j1;
  int M5[4];
  int M6[4];

  int qp_per = (img->qp-MIN_QP)/6;
  int qp_rem = (img->qp-MIN_QP)%6;

  // horizontal
  for (j=0;j<4;j++)
  {
    for (i=0;i<4;i++)
      M5[i]=img->cof[i][j][0][0];

    M6[0]=M5[0]+M5[2];
    M6[1]=M5[0]-M5[2];
    M6[2]=M5[1]-M5[3];
    M6[3]=M5[1]+M5[3];

    for (i=0;i<2;i++)
    {
      i1=3-i;
      img->cof[i ][j][0][0]= M6[i]+M6[i1];
      img->cof[i1][j][0][0]=M6[i]-M6[i1];
    }
  }

  // vertical
  for (i=0;i<4;i++)
  {
    for (j=0;j<4;j++)
      M5[j]=img->cof[i][j][0][0];

    M6[0]=M5[0]+M5[2];
    M6[1]=M5[0]-M5[2];
    M6[2]=M5[1]-M5[3];
    M6[3]=M5[1]+M5[3];

    for (j=0;j<2;j++)
    {
      j1=3-j;
      img->cof[i][j][0][0] = (((M6[j]+M6[j1])*dequant_coef[qp_rem][0][0]<<qp_per)+2)>>2;
      img->cof[i][j1][0][0]= (((M6[j]-M6[j1])*dequant_coef[qp_rem][0][0]<<qp_per)+2)>>2;
    }
  }
}


void itrans_sp(struct img_par *img,  //!< image parameters
               int ioff,             //!< index to 4x4 block
               int joff,             //!<
               int i0,               //!<
               int j0)               //!<
{
  int i,j,i1,j1;
  int m5[4];
  int m6[4];