fmo.c

H.264编码解码器源码(c语言).zip

/*!
 ************************************************************************
 * \brief
 *    FmoGetLastMBInSliceGroup: Returns MB number of last MB in SG
 *
 * \par Input:
 *    SliceGroupID (0 to 7)
 ************************************************************************
 */

int FmoGetLastMBInSliceGroup (int SliceGroup)
{
  int i;
  
  for (i=img->PicSizeInMbs-1; i>=0; i--)
    if (FmoGetSliceGroupId (i) == SliceGroup)
      return i;
  return -1;

};


/*!
 ************************************************************************
 * \brief
 *    Returns SliceGroupID for a given MB
 *
 * \param mb
 *    Macroblock number (in scan order)
 ************************************************************************
 */
int FmoGetSliceGroupId (int mb)
{
  assert (mb < (int)img->PicSizeInMbs);
  assert (MbToSliceGroupMap != NULL);
  return MbToSliceGroupMap[mb];
}


/*!
 ************************************************************************
 * \brief
 *    FmoGetNextMBBr: Returns the MB-Nr (in scan order) of the next
 *    MB in the (scattered) Slice, -1 if the slice is finished
 *
 * \param CurrentMbNr
 *    number of the current macroblock
 ************************************************************************
 */
int FmoGetNextMBNr (int CurrentMbNr)
{
  int SliceGroup = FmoGetSliceGroupId (CurrentMbNr);
  
  while (++CurrentMbNr<(int)img->PicSizeInMbs && MbToSliceGroupMap [CurrentMbNr] != SliceGroup)
    ;

  if (CurrentMbNr >= (int)img->PicSizeInMbs)
    return -1;    // No further MB in this slice (could be end of picture)
  else
    return CurrentMbNr;
}


/*!
 ************************************************************************
 * \brief
 *    Generate interleaved slice group map type MapUnit map (type 0)
 *
 ************************************************************************
 */
static void FmoGenerateType0MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  unsigned iGroup, j;
  unsigned i = 0;
  do
  {
    for( iGroup = 0; 
         (iGroup <= pps->num_slice_groups_minus1) && (i < PicSizeInMapUnits); 
         i += pps->run_length_minus1[iGroup++] + 1 )
    {
      for( j = 0; j <= pps->run_length_minus1[ iGroup ] && i + j < PicSizeInMapUnits; j++ )
        MapUnitToSliceGroupMap[i+j] = iGroup;
    }
  }
  while( i < PicSizeInMapUnits );
}


/*!
 ************************************************************************
 * \brief
 *    Generate dispersed slice group map type MapUnit map (type 1)
 *
 ************************************************************************
 */
static void FmoGenerateType1MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  unsigned i;
  for( i = 0; i < PicSizeInMapUnits; i++ )
  {
    MapUnitToSliceGroupMap[i] = ((i%img->PicWidthInMbs)+(((i/img->PicWidthInMbs)*(pps->num_slice_groups_minus1+1))/2))
		                            %(pps->num_slice_groups_minus1+1);
  }
}

/*!
 ************************************************************************
 * \brief
 *    Generate foreground with left-over slice group map type MapUnit map (type 2)
 *
 ************************************************************************
 */
static void FmoGenerateType2MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  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)
 *
 ************************************************************************
 */
static void FmoGenerateType3MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  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)
 *
 ************************************************************************
 */
static void FmoGenerateType4MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  
  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 ] = 1 - pps->slice_group_change_direction_flag;
    else
        MapUnitToSliceGroupMap[ i ] = pps->slice_group_change_direction_flag;

}

/*!
 ************************************************************************
 * \brief
 *    Generate wipe slice group map type MapUnit map (type 5)
 *
 ************************************************************************
 */
static void FmoGenerateType5MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  
  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)
 *
 ************************************************************************
 */
static void FmoGenerateType6MapUnitMap (pic_parameter_set_rbsp_t* pps, seq_parameter_set_rbsp_t* sps, unsigned PicSizeInMapUnits )
{
  unsigned i;
  for (i=0; i<PicSizeInMapUnits; i++)
  {
    MapUnitToSliceGroupMap[i] = pps->slice_group_id[i];
  }
}