getpic.c

h263解码程序.。。。。。。。。。。。

      BMVx = sign (xvec) * (roundtab[abs (xvec) % 16] + (abs (xvec) / 16) * 2);
      BMVy = sign (yvec) * (roundtab[abs (yvec) % 16] + (abs (yvec) / 16) * 2);
    }
  } else
  {
    if (comp < 4)
    {
      /* luma */
      mvx = MV[0][0][y][x];
      mvy = MV[1][0][y][x];
      BMVx = (bdx == 0 ? (trb - trd) * mvx / trd : trb * mvx / trd + bdx - mvx);
      BMVy = (bdy == 0 ? (trb - trd) * mvy / trd : trb * mvy / trd + bdy - mvy);
    } else
    {
      /* chroma */
      mvx = MV[0][0][y][x];
      mvy = MV[1][0][y][x];
      xvec = (bdx == 0 ? (trb - trd) * mvx / trd : trb * mvx / trd + bdx - mvx);
      yvec = (bdy == 0 ? (trb - trd) * mvy / trd : trb * mvy / trd + bdy - mvy);
      xvec *= 4;
      yvec *= 4;

      /* chroma rounding (table 16/H.263) */
      BMVx = sign (xvec) * (roundtab[abs (xvec) % 16] + (abs (xvec) / 16) * 2);
      BMVy = sign (yvec) * (roundtab[abs (yvec) % 16] + (abs (yvec) / 16) * 2);
    }
  }

  cc = (comp < 4) ? 0 : (comp & 1) + 1; /* color component index */

  if (cc == 0)
  {
    /* luminance */
    find_bidir_limits (BMVx, &xa, &xb, comp & 1);
    find_bidir_limits (BMVy, &ya, &yb, (comp & 2) >> 1);
    bfr = bframe[0] +
      coded_picture_width * (by + ((comp & 2) << 2)) + bx + ((comp & 1) << 3);
    ffr = current_frame[0] +
      coded_picture_width * (by + ((comp & 2) << 2)) + bx + ((comp & 1) << 3);
    ii = coded_picture_width;
  } else
  {
    /* chrominance */
    /* scale coordinates and vectors */
    bx >>= 1;
    by >>= 1;

    find_bidir_chroma_limits (BMVx, &xa, &xb);
    find_bidir_chroma_limits (BMVy, &ya, &yb);

    bfr = bframe[cc] + chrom_width * (by + ((comp & 2) << 2)) + bx + (comp & 8);
    ffr = current_frame[cc] + chrom_width * (by + ((comp & 2) << 2)) + bx + (comp & 8);
    ii = chrom_width;
  }

  xint = BMVx >> 1;
  xhalf = BMVx - 2 * xint;
  yint = BMVy >> 1;
  yhalf = BMVy - 2 * yint;

  ffr += xint + (yint + ya) * ii;
  bfr += ya * ii;

  if (!xhalf && !yhalf)
  {
    for (j = ya; j < yb; j++)
    {
      for (i = xa; i < xb; i++)
      {
        pel = ffr[i];
        bfr[i] = ((unsigned int) (pel + bfr[i])) >> 1;
      }
      bfr += ii;
      ffr += ii;
    }
  } else if (xhalf && !yhalf)
  {
    for (j = ya; j < yb; j++)
    {
      for (i = xa; i < xb; i++)
      {
        pel = ((unsigned int) (ffr[i] + ffr[i + 1] + 1)) >> 1;
        bfr[i] = ((unsigned int) (pel + bfr[i])) >> 1;
      }
      bfr += ii;
      ffr += ii;
    }
  } else if (!xhalf && yhalf)
  {
    for (j = ya; j < yb; j++)
    {
      for (i = xa; i < xb; i++)
      {
        pel = ((unsigned int) (ffr[i] + ffr[ii + i] + 1)) >> 1;
        bfr[i] = ((unsigned int) (pel + bfr[i])) >> 1;
      }
      bfr += ii;
      ffr += ii;
    }
  } else
  {                             /* if (xhalf && yhalf) */
    for (j = ya; j < yb; j++)
    {
      for (i = xa; i < xb; i++)
      {
        pel = ((unsigned int) (ffr[i] + ffr[i + 1] + ffr[ii + i] + ffr[ii + i + 1] + 2)) >> 2;
        bfr[i] = ((unsigned int) (pel + bfr[i])) >> 1;
      }
      bfr += ii;
      ffr += ii;
    }
  }
  return;
}

int motion_decode (int vec, int pmv)
{
  if (vec > 31)
    vec -= 64;
  vec += pmv;
  if (!long_vectors)
  {
    if (vec > 31)
      vec -= 64;
    if (vec < -32)
      vec += 64;
  } else
  {
    if (pmv < -31 && vec < -63)
      vec += 64;
    if (pmv > 32 && vec > 63)
      vec -= 64;
  }
  return vec;
}


int find_pmv (int x, int y, int block, int comp)
{
  int p1, p2, p3;
  int xin1, xin2, xin3;
  int yin1, yin2, yin3;
  int vec1, vec2, vec3;
  int l8, o8, or8;

  x++;
  y++;

  l8 = (modemap[y][x - 1] == MODE_INTER4V ? 1 : 0);
  l8 = (modemap[y][x - 1] == MODE_INTER4V_Q ? 1 : l8);

  o8 = (modemap[y - 1][x] == MODE_INTER4V ? 1 : 0);
  o8 = (modemap[y - 1][x] == MODE_INTER4V_Q ? 1 : o8);

  or8 = (modemap[y - 1][x + 1] == MODE_INTER4V ? 1 : 0);
  or8 = (modemap[y - 1][x + 1] == MODE_INTER4V_Q ? 1 : or8);


  switch (block)
  {
    case 0:
      vec1 = (l8 ? 2 : 0);
      yin1 = y;
      xin1 = x - 1;
      vec2 = (o8 ? 3 : 0);
      yin2 = y - 1;
      xin2 = x;
      vec3 = (or8 ? 3 : 0);
      yin3 = y - 1;
      xin3 = x + 1;
      break;
    case 1:
      vec1 = (l8 ? 2 : 0);
      yin1 = y;
      xin1 = x - 1;
      vec2 = (o8 ? 3 : 0);
      yin2 = y - 1;
      xin2 = x;
      vec3 = (or8 ? 3 : 0);
      yin3 = y - 1;
      xin3 = x + 1;
      break;
    case 2:
      vec1 = 1;
      yin1 = y;
      xin1 = x;
      vec2 = (o8 ? 4 : 0);
      yin2 = y - 1;
      xin2 = x;
      vec3 = (or8 ? 3 : 0);
      yin3 = y - 1;
      xin3 = x + 1;
      break;
    case 3:
      vec1 = (l8 ? 4 : 0);
      yin1 = y;
      xin1 = x - 1;
      vec2 = 1;
      yin2 = y;
      xin2 = x;
      vec3 = 2;
      yin3 = y;
      xin3 = x;
      break;
    case 4:
      vec1 = 3;
      yin1 = y;
      xin1 = x;
      vec2 = 1;
      yin2 = y;
      xin2 = x;
      vec3 = 2;
      yin3 = y;
      xin3 = x;
      break;
    case 5:
      vec1 = 5;
      yin1 = y;
      xin1 = x - 1;
      vec2 = 5;
      yin2 = y - 1;
      xin2 = x;
      vec3 = 5;
      yin3 = y - 1;
      xin3 = x + 1;
      break;
    default:
      fprintf (stderr, "Illegal block number in find_pmv (getpic.c)\n");
      exit (1);
      break;
  }
  p1 = MV[comp][vec1][yin1][xin1];
  p2 = MV[comp][vec2][yin2][xin2];
  p3 = MV[comp][vec3][yin3][xin3];

  if (newgob && (block == 0 || block == 1 || block == 2))
    p2 = NO_VEC;

  if (p2 == NO_VEC)
  {
    p2 = p3 = p1;
  }
  return p1 + p2 + p3 - mmax (p1, mmax (p2, p3)) - mmin (p1, mmin (p2, p3));
}



void find_bidir_limits (int vec, int *start, int *stop, int nhv)
{
  /* limits taken from C loop in section G5 in H.263 */
  *start = mmax (0, (-vec + 1) / 2 - nhv * 8);
  *stop = mmin (7, 15 - (vec + 1) / 2 - nhv * 8);

  (*stop)++;                    /* I use < and not <= in the loop */
}

void find_bidir_chroma_limits (int vec, int *start, int *stop)
{

  /* limits taken from C loop in section G5 in H.263 */
  *start = mmax (0, (-vec + 1) / 2);
  *stop = mmin (7, 7 - (vec + 1) / 2);

  (*stop)++;                    /* I use < and not <= in the loop */
  return;
}

void make_edge_image (unsigned char *src, unsigned char *dst, 
                      int width, int height, int edge)
{
  int i, j;
  unsigned char *p1, *p2, *p3, *p4;
  unsigned char *o1, *o2, *o3, *o4;

  /* center image */
  p1 = dst;
  o1 = src;
  for (j = 0; j < height; j++)
  {
    for (i = 0; i < width; i++)
    {
      *(p1 + i) = *(o1 + i);
    }
    p1 += width + (edge << 1);
    o1 += width;
  }

  /* left and right edges */
  p1 = dst - 1;
  o1 = src;
  for (j = 0; j < height; j++)
  {
    for (i = 0; i < edge; i++)
    {
      *(p1 - i) = *o1;
      *(p1 + width + i + 1) = *(o1 + width - 1);
    }
    p1 += width + (edge << 1);
    o1 += width;
  }

  /* top and bottom edges */
  p1 = dst;
  p2 = dst + (width + (edge << 1)) * (height - 1);
  o1 = src;
  o2 = src + width * (height - 1);
  for (j = 0; j < edge; j++)
  {
    p1 = p1 - (width + (edge << 1));
    p2 = p2 + (width + (edge << 1));
    for (i = 0; i < width; i++)
    {
      *(p1 + i) = *(o1 + i);
      *(p2 + i) = *(o2 + i);
    }
  }

  /* corners */
  p1 = dst - (width + (edge << 1)) - 1;
  p2 = p1 + width + 1;
  p3 = dst + (width + (edge << 1)) * (height) - 1;
  p4 = p3 + width + 1;

  o1 = src;
  o2 = o1 + width - 1;
  o3 = src + width * (height - 1);
  o4 = o3 + width - 1;
  for (j = 0; j < edge; j++)
  {
    for (i = 0; i < edge; i++)
    {
      *(p1 - i) = *o1;
      *(p2 + i) = *o2;
      *(p3 - i) = *o3;
      *(p4 + i) = *o4;
    }
    p1 = p1 - (width + (edge << 1));
    p2 = p2 - (width + (edge << 1));
    p3 = p3 + width + (edge << 1);
    p4 = p4 + width + (edge << 1);
  }

}

/**********************************************************************
 *
 *	Name:           Intra_AC_DC_Decode
 *	Description:    Intra Prediction in Advanced Intra Coding
 *
 *	Input:	        store_qcoeff, Intra_AC_DC, position of MB, store_QP
 *
 *	Side effects:   change qcoeff to predicted qcoeff
 *
 *      Return:
 *
 *	Date:970717     Guy Cote <[e-mail]>
 *
 ***********************************************************************/


void Intra_AC_DC_Decode (short *store_qcoeff, int INTRA_AC_DC, int MBA, int xpos, int ypos, int comp, int newgob)
{

  int A[8], B[8];
  int i, j, tempDC;
  short *Rec_C;
  short *rcoeff;


  Rec_C = ld->block[comp];

  if (xpos == 0 && ypos == 0)
  {                             /* top left corner */
    (comp == 2 || comp == 3) ? fill_A (A, store_qcoeff, xpos, ypos, comp - 2) : fill_null (A);
    (comp == 1 || comp == 3) ? fill_B (B, store_qcoeff, xpos, ypos, comp - 1) : fill_null (B);
  } else
  {                             /* left border of picture */
    if (xpos == 0)
    {                           /* left edge of the picture */
      (comp == 2 || comp == 3) ? fill_A (A, store_qcoeff, xpos, ypos, comp - 2) :
        ((comp == 0 || comp == 1) && !(newgob)) ? fill_A (A, store_qcoeff, xpos, ypos - 1, comp + 2) :
        ((comp == 4 || comp == 5) && !(newgob)) ? fill_A (A, store_qcoeff, xpos, ypos - 1, comp) : fill_null (A);
      (comp == 1 || comp == 3) ? fill_B (B, store_qcoeff, xpos, ypos, comp - 1) : fill_null (B);
    } else
    {
      if (ypos == 0)
      {                         /* top border of picture */
        (comp == 2 || comp == 3) ? fill_A (A, store_qcoeff, xpos, ypos, comp - 2) : fill_null (A);
        (comp == 4 || comp == 5) ? fill_B (B, store_qcoeff, xpos - 1, ypos, comp) :
          (comp == 1 || comp == 3) ? fill_B (B, store_qcoeff, xpos, ypos, comp - 1) :
          fill_B (B, store_qcoeff, xpos - 1, ypos, comp + 1);
      } else
      {                         /* anywhere else in the picture, do not
                                 * cross GOB boundary */
        (comp == 2 || comp == 3) ? fill_A (A, store_qcoeff, xpos, ypos, comp - 2) :
          ((comp == 0 || comp == 1) && !(newgob)) ? fill_A (A, store_qcoeff, xpos, ypos - 1, comp + 2) :
          ((comp == 4 || comp == 5) && !(newgob)) ? fill_A (A, store_qcoeff, xpos, ypos - 1, comp) : fill_null (A);

        (comp == 4 || comp == 5) ? fill_B (B, store_qcoeff, xpos - 1, ypos, comp) :
          (comp == 1 || comp == 3) ? fill_B (B, store_qcoeff, xpos, ypos, comp - 1) :
          fill_B (B, store_qcoeff, xpos - 1, ypos, comp + 1);
      }
    }
  }


  /* replace the qcoeff with the predicted values pcoeff */
  switch (INTRA_AC_DC)
  {
    case INTRA_MODE_DC:

      tempDC = Rec_C[0] + ((A[0] == 1024 && B[0] == 1024) ? 1024 :
                           (A[0] == 1024) ? B[0] :
                           (B[0] == 1024) ? A[0] : (A[0] + B[0]) / 2);
      for (i = 0; i < 8; i++)
        for (j = 0; j < 8; j++)
          Rec_C[i * 8 + j] = clipAC (Rec_C[i * 8 + j]);
      Rec_C[0] = oddifyclipDC (tempDC);
      break;
    case INTRA_MODE_VERT_AC:
      tempDC = Rec_C[0] + A[0];
      for (i = 1; i < 8; i++)
      {
        rcoeff = &Rec_C[i];
        *rcoeff = clipAC (Rec_C[i] + A[i]);
      }
      for (i = 1; i < 8; i++)
        for (j = 0; j < 8; j++)
          Rec_C[i * 8 + j] = clipAC (Rec_C[i * 8 + j]);
      Rec_C[0] = oddifyclipDC (tempDC);
      break;
    case INTRA_MODE_HORI_AC:
      tempDC = Rec_C[0] + B[0];
      for (i = 1; i < 8; i++)
        Rec_C[i * 8] = clipAC (Rec_C[i * 8] + B[i]);
      for (i = 0; i < 8; i++)
        for (j = 1; j < 8; j++)
          Rec_C[i * 8 + j] = clipAC (Rec_C[i * 8 + j]);
      Rec_C[0] = oddifyclipDC (tempDC);
      break;