fmo.c

G729、h263、h264、MPEG4四种最流行的音频和视频标准的压缩和解压算法的源代码.rar

 * \param pps
 *    Picture Parameter set to be used for map generation
 ************************************************************************
 */
static void FmoGenerateType2MapUnitMap (ImageParameters * img, pic_parameter_set_rbsp_t * pps )
{
  int iGroup;
  unsigned i, x, y;
  unsigned yTopLeft, xTopLeft, yBottomRight, xBottomRight;
  
  for( i = 0; i < PicSizeInMapUnits; i++ )
    MapUnitToSliceGroupMap[ i ] = pps->num_slice_groups_minus1;
  
  for( iGroup = pps->num_slice_groups_minus1 - 1 ; iGroup >= 0; iGroup-- ) 
  {
    yTopLeft = pps->top_left[ iGroup ] / img->PicWidthInMbs;
    xTopLeft = pps->top_left[ iGroup ] % img->PicWidthInMbs;
    yBottomRight = pps->bottom_right[ iGroup ] / img->PicWidthInMbs;
    xBottomRight = pps->bottom_right[ iGroup ] % img->PicWidthInMbs;
    for( y = yTopLeft; y <= yBottomRight; y++ )
      for( x = xTopLeft; x <= xBottomRight; x++ )
        MapUnitToSliceGroupMap[ y * img->PicWidthInMbs + x ] = iGroup;
  }
}


/*!
 ************************************************************************
 * \brief
 *    Generate box-out slice group map type MapUnit map (type 3)
 *
 * \param img
 *    Image Parameter to be used for map generation
 * \param pps
 *    Picture Parameter set to be used for map generation
 ************************************************************************
 */
static void FmoGenerateType3MapUnitMap (ImageParameters * img, pic_parameter_set_rbsp_t * pps )
{
  unsigned i, k;
  int leftBound, topBound, rightBound, bottomBound;
  int x, y, xDir, yDir;
  int mapUnitVacant;
  
  unsigned mapUnitsInSliceGroup0 = min((pps->slice_group_change_rate_minus1 + 1) * img->slice_group_change_cycle, PicSizeInMapUnits);
  
  for( i = 0; i < PicSizeInMapUnits; i++ )
    MapUnitToSliceGroupMap[ i ] = 2;
  
  x = ( img->PicWidthInMbs - pps->slice_group_change_direction_flag ) / 2;
  y = ( img->PicHeightInMapUnits - pps->slice_group_change_direction_flag ) / 2;
  
  leftBound   = x;
  topBound    = y;
  rightBound  = x;
  bottomBound = y;
  
  xDir =  pps->slice_group_change_direction_flag - 1;
  yDir =  pps->slice_group_change_direction_flag;
  
  for( k = 0; k < PicSizeInMapUnits; k += mapUnitVacant ) 
  {
    mapUnitVacant = ( MapUnitToSliceGroupMap[ y * img->PicWidthInMbs + x ]  ==  2 );
    if( mapUnitVacant )
      MapUnitToSliceGroupMap[ y * img->PicWidthInMbs + x ] = ( k >= mapUnitsInSliceGroup0 );
    
    if( xDir  ==  -1  &&  x  ==  leftBound ) 
    {
      leftBound = max( leftBound - 1, 0 );
      x = leftBound;
      xDir = 0;
      yDir = 2 * pps->slice_group_change_direction_flag - 1;
    }
    else 
      if( xDir  ==  1  &&  x  ==  rightBound ) 
      {
        rightBound = min( rightBound + 1, (int)img->PicWidthInMbs - 1 );
        x = rightBound;
        xDir = 0;
        yDir = 1 - 2 * pps->slice_group_change_direction_flag;
      }
      else
        if( yDir  ==  -1  &&  y  ==  topBound ) 
        {
          topBound = max( topBound - 1, 0 );
          y = topBound;
          xDir = 1 - 2 * pps->slice_group_change_direction_flag;
          yDir = 0;
        }
        else 
          if( yDir  ==  1  &&  y  ==  bottomBound ) 
          {
            bottomBound = min( bottomBound + 1, (int)img->PicHeightInMapUnits - 1 );
            y = bottomBound;
            xDir = 2 * pps->slice_group_change_direction_flag - 1;
            yDir = 0;
          }
          else
          {
            x = x + xDir;
            y = y + yDir;
          }
  }
  
}

/*!
 ************************************************************************
 * \brief
 *    Generate raster scan slice group map type MapUnit map (type 4)
 *
 * \param img
 *    Image Parameter to be used for map generation
 * \param pps
 *    Picture Parameter set to be used for map generation
 ************************************************************************
 */
static void FmoGenerateType4MapUnitMap (ImageParameters * img, pic_parameter_set_rbsp_t * pps )
{
  
  unsigned mapUnitsInSliceGroup0 = min((pps->slice_group_change_rate_minus1 + 1) * img->slice_group_change_cycle, PicSizeInMapUnits);
  unsigned sizeOfUpperLeftGroup = pps->slice_group_change_direction_flag ? ( PicSizeInMapUnits - mapUnitsInSliceGroup0 ) : mapUnitsInSliceGroup0;
  
  unsigned i;
  
  for( i = 0; i < PicSizeInMapUnits; i++ )
    if( i < sizeOfUpperLeftGroup )
      MapUnitToSliceGroupMap[ i ] = pps->slice_group_change_direction_flag;
    else
      MapUnitToSliceGroupMap[ i ] = 1 - pps->slice_group_change_direction_flag;
    
}

/*!
 ************************************************************************
 * \brief
 *    Generate wipe slice group map type MapUnit map (type 5)
 *
 * \param img
 *    Image Parameter to be used for map generation
 * \param pps
 *    Picture Parameter set to be used for map generation
 ************************************************************************
*/
static void FmoGenerateType5MapUnitMap (ImageParameters * img, pic_parameter_set_rbsp_t * pps )
{
  
  unsigned mapUnitsInSliceGroup0 = min((pps->slice_group_change_rate_minus1 + 1) * img->slice_group_change_cycle, PicSizeInMapUnits);
  unsigned sizeOfUpperLeftGroup = pps->slice_group_change_direction_flag ? ( PicSizeInMapUnits - mapUnitsInSliceGroup0 ) : mapUnitsInSliceGroup0;
  
  unsigned i,j, k = 0;
  
  for( j = 0; j < img->PicWidthInMbs; j++ )
    for( i = 0; i < img->PicHeightInMapUnits; i++ )
      if( k++ < sizeOfUpperLeftGroup )
        MapUnitToSliceGroupMap[ i * img->PicWidthInMbs + j ] = 1 - pps->slice_group_change_direction_flag;
      else
        MapUnitToSliceGroupMap[ i * img->PicWidthInMbs + j ] = pps->slice_group_change_direction_flag;
      
}

/*!
 ************************************************************************
 * \brief
 *    Generate explicit slice group map type MapUnit map (type 6)
 *
 * \param img
 *    Image Parameter to be used for map generation
 * \param pps
 *    Picture Parameter set to be used for map generation
 ************************************************************************
 */
static void FmoGenerateType6MapUnitMap (ImageParameters * img, pic_parameter_set_rbsp_t * pps )
{
  unsigned i;
  for (i=0; i<PicSizeInMapUnits; i++)
  {
    MapUnitToSliceGroupMap[i] = pps->slice_group_id[i];
  }
}

/*!
 ************************************************************************
 * \brief
 *    FmoStartPicture: initializes FMO at the begin of each new picture
 *
 * \par Input:
 *    None
 ************************************************************************
 */
int FmoStartPicture ()
{
  int i;
  
  assert (MBAmap != NULL);
  
  for (i=0; i<MAXSLICEGROUPIDS; i++)
    FirstMBInSlice[i] = FmoGetFirstMBOfSliceGroup (i);
  return 0;
}



/*!
 ************************************************************************
 * \brief
 *    FmoEndPicture: Ends the Scattered Slices Module (called once
 *    per picture).
 *
 * \par Input:
 *    None
 ************************************************************************
 */
int FmoEndPicture ()
{
  // Do nothing
  return 0;
}


/*!
 ************************************************************************
 * \brief
 *    FmoMB2Slice: Returns SliceID for a given MB
 *
 * \par Input:
 *    Macroblock Nr (in scan order)
 ************************************************************************
 */
int FmoMB2SliceGroup ( int mb)
{
  assert (mb < (int)img->PicSizeInMbs);
  assert (MBAmap != NULL);
  return MBAmap[mb];
}

/*!
 ************************************************************************
 * \brief
 *    FmoGetNextMBBr: Returns the MB-Nr (in scan order) of the next
 *    MB in the (FMO) Slice, -1 if the SliceGroup is finished
 *
 * \par Input:
 *    CurrentMbNr
 ************************************************************************
 */
int FmoGetNextMBNr (int CurrentMbNr)
{
  
  int  SliceGroupID = FmoMB2SliceGroup (CurrentMbNr); 
  
  while (++CurrentMbNr<(int)img->PicSizeInMbs &&  MBAmap[CurrentMbNr] != SliceGroupID)
    ;
  
  if (CurrentMbNr >= (int)img->PicSizeInMbs)
    return -1;    // No further MB in this slice (could be end of picture)
  else
    return CurrentMbNr;
}


/*!
 ************************************************************************
 * \brief
 *    FmoGetNextMBBr: Returns the MB-Nr (in scan order) of the next
 *    MB in the (FMO) Slice, -1 if the SliceGroup is finished
 *
 * \par Input:
 *    CurrentMbNr
 ************************************************************************
 */
int FmoGetPreviousMBNr (int CurrentMbNr)
{
  
  int  SliceGroupID = FmoMB2SliceGroup (CurrentMbNr); 
  CurrentMbNr--;
  while (CurrentMbNr>=0 &&  MBAmap[CurrentMbNr] != SliceGroupID)
    CurrentMbNr--;
  
  if (CurrentMbNr < 0)
    return -1;    // No previous MB in this slice
  else
    return CurrentMbNr;
}


/*!
 ************************************************************************
 * \brief
 *    FmoGetFirstMBOfSliceGroup: Returns the MB-Nr (in scan order) of the 
 *    next first MB of the Slice group, -1 if no such MB exists
 *
 * \par Input:
 *    SliceGroupID: Id of SliceGroup
 ************************************************************************
 */
int FmoGetFirstMBOfSliceGroup (int SliceGroupID)
{
  int i = 0;
  while ((i<(int)img->PicSizeInMbs) && (FmoMB2SliceGroup (i) != SliceGroupID))
    i++;

  if (i < (int)img->PicSizeInMbs)
    return i;
  else
    return -1;
}


/*!
 ************************************************************************
 * \brief
 *    FmoGetLastCodedMBOfSlice: Returns the MB-Nr (in scan order) of 
 *    the last MB of the slice group
 *
 * \par Input:
 *    SliceGroupID
 * \par Return
 *    MB Nr in case of success (is always >= 0)
 *    -1 if the SliceGroup doesn't exist
 ************************************************************************
 */
int FmoGetLastCodedMBOfSliceGroup (int SliceGroupID)
{
  int i;
  int LastMB = -1;
  
  for (i=0; i<(int)img->PicSizeInMbs; i++)
    if (FmoMB2SliceGroup (i) == SliceGroupID)
      LastMB = i;
  return LastMB;
}


void FmoSetLastMacroblockInSlice ( int mb)
{
  // called by terminate_slice(), writes the last processed MB into the
  // FirstMBInSlice[MAXSLICEGROUPIDS] array.  FmoGetFirstMacroblockInSlice()
  // uses this info to identify the first uncoded MB in each slice group
  
  int currSliceGroup = FmoMB2SliceGroup (mb);
  assert (mb >= 0);
  mb = FmoGetNextMBNr (mb);   // The next (still uncoded) MB, or -1 if SG is finished
  FirstMBInSlice[currSliceGroup] = mb;
}

int FmoGetFirstMacroblockInSlice ( int SliceGroup)
{
  return FirstMBInSlice[SliceGroup];
  // returns the first uncoded MB in each slice group, -1 if there is no
  // more to do in this slice group
}


int FmoSliceGroupCompletelyCoded( int SliceGroupID)
{
  if (FmoGetFirstMacroblockInSlice (SliceGroupID) < 0)  // slice group completelty coded or not present
    return TRUE;
  else
    return FALSE;
}