block.c

jm61 的源代码

        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;
          M0[i][ii][ j][jj]=M6[j]+M6[j1];
          M0[i][ii][j1][jj]=M6[j]-M6[j1];

        }
      }

    }
  }

  for (j=0;j<16;j++)
  {
    for (i=0;i<16;i++)
    {
      M1[i][j]=M0[i%4][i/4][j%4][j/4];
    }
  }

  for (j=0;j<16;j++)
    for (i=0;i<16;i++)
      imgY[img->pix_y+j][img->pix_x+i]=(byte)min(255,max(0,(M1[i][j]+(img->mprr_2[new_intra_mode][j][i]<<DQ_BITS)+DQ_ROUND)>>DQ_BITS));

    return ac_coef;
}


/*!
 ************************************************************************
 * \brief
 *    The routine performs transform,quantization,inverse transform, adds the diff.
 *    to the prediction and writes the result to the decoded luma frame. Includes the
 *    RD constrained quantization also.
 *
 * \para Input:
 *    block_x,block_y: Block position inside a macro block (0,4,8,12).
 *
 * \para Output_
 *    nonzero: 0 if no levels are nonzero.  1 if there are nonzero levels.             \n
 *    coeff_cost: Counter for nonzero coefficients, used to discard expencive levels.
 ************************************************************************
 */
int dct_luma(int block_x,int block_y,int *coeff_cost, int old_intra_mode)
{
  int sign(int a,int b);

  int i,j,i1,j1,ilev,m5[4],m6[4],coeff_ctr;
  int qp_const,level,scan_pos,run;
  int nonzero;
  int qp_per,qp_rem,q_bits;

  int   pos_x   = block_x/BLOCK_SIZE;
  int   pos_y   = block_y/BLOCK_SIZE;
  int   b8      = 2*(pos_y/2) + (pos_x/2);
  int   b4      = 2*(pos_y%2) + (pos_x%2);
  int*  ACLevel = img->cofAC[b8][b4][0];
  int*  ACRun   = img->cofAC[b8][b4][1];

  qp_per    = (img->qp-MIN_QP)/6;
  qp_rem    = (img->qp-MIN_QP)%6;
  q_bits    = Q_BITS+qp_per;

  if (img->type == INTRA_IMG)
    qp_const=(1<<q_bits)/3;    // intra
  else
    qp_const=(1<<q_bits)/6;    // inter

  //  Horizontal transform
  for (j=0; j < BLOCK_SIZE; j++)
  {
    for (i=0; i < 2; i++)
    {
      i1=3-i;
      m5[i]=img->m7[i][j]+img->m7[i1][j];
      m5[i1]=img->m7[i][j]-img->m7[i1][j];
    }
    img->m7[0][j]=(m5[0]+m5[1]);
    img->m7[2][j]=(m5[0]-m5[1]);
    img->m7[1][j]=m5[3]*2+m5[2];
    img->m7[3][j]=m5[3]-m5[2]*2;
  }

  //  Vertival transform
  for (i=0; i < BLOCK_SIZE; i++)
  {
    for (j=0; j < 2; j++)
    {
      j1=3-j;
      m5[j]=img->m7[i][j]+img->m7[i][j1];
      m5[j1]=img->m7[i][j]-img->m7[i][j1];
    }
    img->m7[i][0]=(m5[0]+m5[1]);
    img->m7[i][2]=(m5[0]-m5[1]);
    img->m7[i][1]=m5[3]*2+m5[2];
    img->m7[i][3]=m5[3]-m5[2]*2;
  }

  // Quant

  nonzero=FALSE;

  run=-1;
  scan_pos=0;
  
  for (coeff_ctr=0;coeff_ctr < 16;coeff_ctr++)
  {

    if (img->field_picture || ( mb_adaptive && img->field_mode )) 
    {  // Alternate scan for field coding
        i=FIELD_SCAN[coeff_ctr][0];
        j=FIELD_SCAN[coeff_ctr][1];
    }
    else 
    {
        i=SNGL_SCAN[coeff_ctr][0];
        j=SNGL_SCAN[coeff_ctr][1];
    }
    
    run++;
    ilev=0;
    
    level = (abs (img->m7[i][j]) * quant_coef[qp_rem][i][j] + qp_const) >> q_bits;
    
    if (level != 0)
    {
      nonzero=TRUE;
      if (level > 1)
        *coeff_cost += MAX_VALUE;                // set high cost, shall not be discarded
      else
        *coeff_cost += COEFF_COST[run];
      ACLevel[scan_pos] = sign(level,img->m7[i][j]);
      ACRun  [scan_pos] = run;
      ++scan_pos;
      run=-1;                     // reset zero level counter
      ilev=level*dequant_coef[qp_rem][i][j]<<qp_per;
    }
    img->m7[i][j]=sign(ilev,img->m7[i][j]);
  }
  ACLevel[scan_pos] = 0;
  
  
  //     IDCT.
  //     horizontal

  for (j=0; j < BLOCK_SIZE; j++)
  {
    for (i=0; i < BLOCK_SIZE; i++)
    {
      m5[i]=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 (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] =min(255,max(0,(m6[j]+m6[j1]+(img->mpr[i+block_x][j+block_y] <<DQ_BITS)+DQ_ROUND)>>DQ_BITS));
      img->m7[i][j1]=min(255,max(0,(m6[j]-m6[j1]+(img->mpr[i+block_x][j1+block_y]<<DQ_BITS)+DQ_ROUND)>>DQ_BITS));
    }
  }

  //  Decoded block moved to frame memory

  for (j=0; j < BLOCK_SIZE; j++)
    for (i=0; i < BLOCK_SIZE; i++)
      imgY[img->pix_y+block_y+j][img->pix_x+block_x+i]=img->m7[i][j];


  return nonzero;
}



/*!
 ************************************************************************
 * \brief
 *    Transform,quantization,inverse transform for chroma.
 *    The main reason why this is done in a separate routine is the
 *    additional 2x2 transform of DC-coeffs. This routine is called
 *    ones for each of the chroma components.
 *
 * \para Input:
 *    uv    : Make difference between the U and V chroma component  \n
 *    cr_cbp: chroma coded block pattern
 *
 * \para Output:
 *    cr_cbp: Updated chroma coded block pattern.
 ************************************************************************
 */
int dct_chroma(int uv,int cr_cbp)
{
  int i,j,i1,j2,ilev,n2,n1,j1,mb_y,coeff_ctr,qp_const,level ,scan_pos,run;
  int m1[BLOCK_SIZE],m5[BLOCK_SIZE],m6[BLOCK_SIZE];
  int coeff_cost;
  int cr_cbp_tmp;
  int nn0,nn1;
  int DCcoded=0 ;
  Macroblock *currMB = &img->mb_data[img->current_mb_nr];

  int qp_per,qp_rem,q_bits;

  int   b4;
  int*  DCLevel = img->cofDC[uv+1][0];
  int*  DCRun   = img->cofDC[uv+1][1];
  int*  ACLevel;
  int*  ACRun;

  qp_per    = QP_SCALE_CR[img->qp-MIN_QP]/6;
  qp_rem    = QP_SCALE_CR[img->qp-MIN_QP]%6;
  q_bits    = Q_BITS+qp_per;

  if (img->type == INTRA_IMG)
    qp_const=(1<<q_bits)/3;    // intra
  else
    qp_const=(1<<q_bits)/6;    // inter

  for (n2=0; n2 <= BLOCK_SIZE; n2 += BLOCK_SIZE)
  {
    for (n1=0; n1 <= BLOCK_SIZE; n1 += BLOCK_SIZE)
    {

      //  Horizontal transform.
      for (j=0; j < BLOCK_SIZE; j++)
      {
        mb_y=n2+j;
        for (i=0; i < 2; i++)
        {
          i1=3-i;
          m5[i]=img->m7[i+n1][mb_y]+img->m7[i1+n1][mb_y];
          m5[i1]=img->m7[i+n1][mb_y]-img->m7[i1+n1][mb_y];
        }
        img->m7[n1][mb_y]  =(m5[0]+m5[1]);
        img->m7[n1+2][mb_y]=(m5[0]-m5[1]);
        img->m7[n1+1][mb_y]=m5[3]*2+m5[2];
        img->m7[n1+3][mb_y]=m5[3]-m5[2]*2;
      }

      //  Vertical transform.

      for (i=0; i < BLOCK_SIZE; i++)
      {
        j1=n1+i;
        for (j=0; j < 2; j++)
        {
          j2=3-j;
          m5[j]=img->m7[j1][n2+j]+img->m7[j1][n2+j2];
          m5[j2]=img->m7[j1][n2+j]-img->m7[j1][n2+j2];
        }
        img->m7[j1][n2+0]=(m5[0]+m5[1]);
        img->m7[j1][n2+2]=(m5[0]-m5[1]);
        img->m7[j1][n2+1]=m5[3]*2+m5[2];
        img->m7[j1][n2+3]=m5[3]-m5[2]*2;
      }
    }
  }

  //     2X2 transform of DC coeffs.
  m1[0]=(img->m7[0][0]+img->m7[4][0]+img->m7[0][4]+img->m7[4][4]);
  m1[1]=(img->m7[0][0]-img->m7[4][0]+img->m7[0][4]-img->m7[4][4]);
  m1[2]=(img->m7[0][0]+img->m7[4][0]-img->m7[0][4]-img->m7[4][4]);
  m1[3]=(img->m7[0][0]-img->m7[4][0]-img->m7[0][4]+img->m7[4][4]);

  //     Quant of chroma 2X2 coeffs.
  run=-1;
  scan_pos=0;

  for (coeff_ctr=0; coeff_ctr < 4; coeff_ctr++)
  {
    run++;
    ilev=0;

    level =(abs(m1[coeff_ctr]) * quant_coef[qp_rem][0][0] + 2*qp_const) >> (q_bits+1);

    if (level  != 0)
    {
      currMB->cbp_blk |= 0xf0000 << (uv << 2) ;    // if one of the 2x2-DC levels is != 0 set the
      cr_cbp=max(1,cr_cbp);                     // coded-bit all 4 4x4 blocks (bit 16-19 or 20-23)
      DCcoded = 1 ;
      DCLevel[scan_pos] = sign(level ,m1[coeff_ctr]);
      DCRun  [scan_pos] = run;
      scan_pos++;
      run=-1;
      ilev=level*dequant_coef[qp_rem][0][0]<<qp_per;
    }
    m1[coeff_ctr]=sign(ilev,m1[coeff_ctr]);
  }
  DCLevel[scan_pos] = 0;

  //  Invers transform of 2x2 DC levels

  img->m7[0][0]=(m1[0]+m1[1]+m1[2]+m1[3])>>1;
  img->m7[4][0]=(m1[0]-m1[1]+m1[2]-m1[3])>>1;
  img->m7[0][4]=(m1[0]+m1[1]-m1[2]-m1[3])>>1;
  img->m7[4][4]=(m1[0]-m1[1]-m1[2]+m1[3])>>1;

  //     Quant of chroma AC-coeffs.
  coeff_cost=0;
  cr_cbp_tmp=0;

  for (n2=0; n2 <= BLOCK_SIZE; n2 += BLOCK_SIZE)
  {
    for (n1=0; n1 <= BLOCK_SIZE; n1 += BLOCK_SIZE)
    {
      b4      = 2*(n2/4) + (n1/4);
      ACLevel = img->cofAC[uv+4][b4][0];
      ACRun   = img->cofAC[uv+4][b4][1];
      run=-1;
      scan_pos=0;

      for (coeff_ctr=1; coeff_ctr < 16; coeff_ctr++)// start change rd_quant
      {

        if (img->field_picture || ( mb_adaptive && img->field_mode )) 
        {  // Alternate scan for field coding
          i=FIELD_SCAN[coeff_ctr][0];
          j=FIELD_SCAN[coeff_ctr][1];
        }
        else 
        {
          i=SNGL_SCAN[coeff_ctr][0];
          j=SNGL_SCAN[coeff_ctr][1];
        }
        ++run;
        ilev=0;

        level=(abs(img->m7[n1+i][n2+j])*quant_coef[qp_rem][i][j]+qp_const)>>q_bits;

        if (level  != 0)
        {
          currMB->cbp_blk |= 1 << (16 + (uv << 2) + ((n2 >> 1) + (n1 >> 2))) ;
          if (level > 1)
            coeff_cost += MAX_VALUE;                // set high cost, shall not be discarded
          else
            coeff_cost += COEFF_COST[run];

          cr_cbp_tmp=2;
          ACLevel[scan_pos] = sign(level,img->m7[n1+i][n2+j]);
          ACRun  [scan_pos] = run;
          ++scan_pos;
          run=-1;
          ilev=level*dequant_coef[qp_rem][i][j]<<qp_per;
        }
        img->m7[n1+i][n2+j]=sign(ilev,img->m7[n1+i][n2+j]); // for use in IDCT
      }
      ACLevel[scan_pos] = 0;
    }
  }

  // * reset chroma coeffs
  if(coeff_cost < _CHROMA_COEFF_COST_)
  {
    cr_cbp_tmp = 0 ;
    for (n2=0; n2 <= BLOCK_SIZE; n2 += BLOCK_SIZE)
    {
      for (n1=0; n1 <= BLOCK_SIZE; n1 += BLOCK_SIZE)
      {
        b4      = 2*(n2/4) + (n1/4);
        ACLevel = img->cofAC[uv+4][b4][0];
        ACRun   = img->cofAC[uv+4][b4][1];
        if( DCcoded == 0) currMB->cbp_blk &= ~(0xf0000 << (uv << 2));  // if no chroma DC's: then reset coded-bits of this chroma subblock
        nn0 = (n1>>2) + (uv<<1);
        nn1 = 4 + (n2>>2) ;
        ACLevel[0] = 0;
        for (coeff_ctr=1; coeff_ctr < 16; coeff_ctr++)// ac coeff
        {

          if (img->field_picture || ( mb_adaptive && img->field_mode )) 
          {  // Alternate scan for field coding
            i=FIELD_SCAN[coeff_ctr][0];
            j=FIELD_SCAN[coeff_ctr][1];
          }
          else 
          {
            i=SNGL_SCAN[coeff_ctr][0];
            j=SNGL_SCAN[coeff_ctr][1];
          }
          img->m7[n1+i][n2+j]=0;
          ACLevel[coeff_ctr] = 0;
        }