mbuffer.c

一个实现H264的c程序

    dpb.used_size=0;
  }
  else
  {
    flush_dpb();
  }
  dpb.last_picture = NULL;

  update_ref_list();
  update_ltref_list();
  dpb.last_output_poc = INT_MIN;
  
  if (img->long_term_reference_flag)
  {
    dpb.max_long_term_pic_idx = 0;
    p->is_long_term           = 1;
    p->long_term_frame_idx    = 0;
  }
  else
  {
    dpb.max_long_term_pic_idx = -1;
    p->is_long_term           = 0;
  }
}

/*!
 ************************************************************************
 * \brief
 *    Perform Sliding window decoded reference picture marking process
 *
 ************************************************************************
 */
static void sliding_window_memory_management(StorablePicture* p)
{
  unsigned i;

  assert (!img->idr_flag);
  // if this is a reference pic with sliding sliding window, unmark first ref frame
  if (dpb.ref_frames_in_buffer==active_sps->num_ref_frames - dpb.ltref_frames_in_buffer)
  {
    for (i=0; i<dpb.used_size;i++)
    {
      if (dpb.fs[i]->is_reference  && (!(dpb.fs[i]->is_long_term)))
      {
        unmark_for_reference(dpb.fs[i]);
        update_ref_list();
        break;
      }
    }
  }

  p->is_long_term = 0;
}

/*!
 ************************************************************************
 * \brief
 *    Calculate picNumX
 ************************************************************************
 */
static int get_pic_num_x (StorablePicture *p, int difference_of_pic_nums_minus1)
{
  int currPicNum;

  if (p->structure == FRAME)
    currPicNum = img->frame_num;
  else 
    currPicNum = 2 * img->frame_num + 1;
  
  return currPicNum - (difference_of_pic_nums_minus1 + 1);
}


/*!
 ************************************************************************
 * \brief
 *    Adaptive Memory Management: Mark short term picture unused
 ************************************************************************
 */
static void mm_unmark_short_term_for_reference(StorablePicture *p, int difference_of_pic_nums_minus1)
{
  int picNumX;

  unsigned i;

  picNumX = get_pic_num_x(p, difference_of_pic_nums_minus1);

  for (i=0; i<dpb.ref_frames_in_buffer; i++)
  {
    if (p->structure == FRAME)
    {
      if ((dpb.fs_ref[i]->is_reference==3) && (dpb.fs_ref[i]->is_long_term==0))
      {
        if (dpb.fs_ref[i]->frame->pic_num == picNumX)
        {
          unmark_for_reference(dpb.fs_ref[i]);
          return;
        }
      }
    }
    else
    {
      if ((dpb.fs_ref[i]->is_reference & 1) && (!(dpb.fs_ref[i]->is_long_term & 1)))
      {
        if (dpb.fs_ref[i]->top_field->pic_num == picNumX)
        {
          dpb.fs_ref[i]->top_field->used_for_reference = 0;
          dpb.fs_ref[i]->is_reference &= 2;
          if (dpb.fs_ref[i]->is_used == 3)
          {
            dpb.fs_ref[i]->frame->used_for_reference = 0;
          }
          return;
        }
      }
      if ((dpb.fs_ref[i]->is_reference & 2) && (!(dpb.fs_ref[i]->is_long_term & 2)))
      {
        if (dpb.fs_ref[i]->bottom_field->pic_num == picNumX)
        {
          dpb.fs_ref[i]->bottom_field->used_for_reference = 0;
          dpb.fs_ref[i]->is_reference &= 1;
          if (dpb.fs_ref[i]->is_used == 3)
          {
            dpb.fs_ref[i]->frame->used_for_reference = 0;
          }
          return;
        }
      }
    }
  }
}


/*!
 ************************************************************************
 * \brief
 *    Adaptive Memory Management: Mark long term picture unused
 ************************************************************************
 */
static void mm_unmark_long_term_for_reference(StorablePicture *p, int long_term_pic_num)
{
  unsigned i;
  for (i=0; i<dpb.ltref_frames_in_buffer; i++)
  {
    if (p->structure == FRAME)
    {
      if ((dpb.fs_ltref[i]->is_reference==3) && (dpb.fs_ltref[i]->is_long_term==3))
      {
        if (dpb.fs_ltref[i]->frame->long_term_pic_num == long_term_pic_num)
        {
          unmark_for_long_term_reference(dpb.fs_ltref[i]);
        }
      }
    }
    else
    {
      if ((dpb.fs_ltref[i]->is_reference & 1) && ((dpb.fs_ltref[i]->is_long_term & 1)))
      {
        if (dpb.fs_ltref[i]->top_field->long_term_pic_num == long_term_pic_num)
        {
          dpb.fs_ltref[i]->top_field->used_for_reference = 0;
          dpb.fs_ltref[i]->top_field->is_long_term = 0;
          dpb.fs_ltref[i]->is_reference &= 2;
          dpb.fs_ltref[i]->is_long_term &= 2;
          if (dpb.fs_ltref[i]->is_used == 3)
          {
            dpb.fs_ltref[i]->frame->used_for_reference = 0;
            dpb.fs_ltref[i]->frame->is_long_term = 0;
          }
          return;
        }
      }
      if ((dpb.fs_ltref[i]->is_reference & 2) && ((dpb.fs_ltref[i]->is_long_term & 2)))
      {
        if (dpb.fs_ltref[i]->bottom_field->long_term_pic_num == long_term_pic_num)
        {
          dpb.fs_ltref[i]->bottom_field->used_for_reference = 0;
          dpb.fs_ltref[i]->bottom_field->is_long_term = 0;
          dpb.fs_ltref[i]->is_reference &= 1;
          dpb.fs_ltref[i]->is_long_term &= 1;
          if (dpb.fs_ltref[i]->is_used == 3)
          {
            dpb.fs_ltref[i]->frame->used_for_reference = 0;
            dpb.fs_ltref[i]->frame->is_long_term = 0;
          }
          return;
        }
      }
    }
  }
}


/*!
 ************************************************************************
 * \brief
 *    Mark a long-term reference frame or complementary field pair unused for referemce
 ************************************************************************
 */
static void unmark_long_term_frame_for_reference_by_frame_idx(int long_term_frame_idx)
{
  unsigned i;
  for(i=0; i<dpb.ltref_frames_in_buffer; i++)
  {
    if (dpb.fs_ltref[i]->long_term_frame_idx == long_term_frame_idx)
      unmark_for_long_term_reference(dpb.fs_ltref[i]);
  }
}

/*!
 ************************************************************************
 * \brief
 *    Mark a long-term reference field unused for referemce only if it's not
 *    the complementary field of the picture indicated by picNumX
 ************************************************************************
 */
static void unmark_long_term_field_for_reference_by_frame_idx(StorablePicture *p, int long_term_frame_idx, int picNumX)
{
  unsigned i;
  for(i=0; i<dpb.ltref_frames_in_buffer; i++)
  {
    if (dpb.fs_ltref[i]->long_term_frame_idx == long_term_frame_idx)
    {
      if (p->structure == TOP_FIELD)
      {
        if (!(dpb.fs_ltref[i]->is_reference == 3))
        {
          unmark_for_long_term_reference(dpb.fs_ltref[i]);
        }
        else
        {
          if (!(dpb.fs_ltref[i]->is_long_term == 2))
          {
            unmark_for_long_term_reference(dpb.fs_ltref[i]);
          }
          else
          {
            if (!(dpb.fs_ltref[i]->top_field->pic_num==picNumX))
              unmark_for_long_term_reference(dpb.fs_ltref[i]);
          }
        }
      }
      if (p->structure == BOTTOM_FIELD)
      {
        if (!(dpb.fs_ltref[i]->is_reference == 3))
        {
          unmark_for_long_term_reference(dpb.fs_ltref[i]);
        }
        else
        {
          if (!(dpb.fs_ltref[i]->is_long_term == 1))
          {
            unmark_for_long_term_reference(dpb.fs_ltref[i]);
          }
          else
          {
            if (!(dpb.fs_ltref[i]->bottom_field->pic_num==picNumX))
            {
              unmark_for_long_term_reference(dpb.fs_ltref[i]);
            }
          }
        }
      }
    }
  }
}


/*!
 ************************************************************************
 * \brief
 *    mark a picture as long-term reference
 ************************************************************************
 */
static void mark_pic_long_term(StorablePicture* p, int long_term_frame_idx, int picNumX)
{
  unsigned i;
  int add_top, add_bottom;

  if (p->structure == FRAME)
  {
    for (i=0; i<dpb.ref_frames_in_buffer; i++)
    {
      if (dpb.fs_ref[i]->is_reference == 3)
      {
        if ((!dpb.fs_ref[i]->frame->is_long_term)&&(dpb.fs_ref[i]->frame->pic_num == picNumX))
        {
          dpb.fs_ref[i]->long_term_frame_idx = dpb.fs_ref[i]->frame->long_term_frame_idx
                                             = dpb.fs_ref[i]->top_field->long_term_frame_idx
                                             = dpb.fs_ref[i]->bottom_field->long_term_frame_idx
                                             = long_term_frame_idx;
          dpb.fs_ref[i]->frame->long_term_pic_num = dpb.fs_ref[i]->top_field->long_term_pic_num
                                                  = dpb.fs_ref[i]->bottom_field->long_term_pic_num
                                                  = long_term_frame_idx;
          dpb.fs_ref[i]->frame->is_long_term = dpb.fs_ref[i]->top_field->is_long_term
                                             = dpb.fs_ref[i]->bottom_field->is_long_term
                                             = 1;
          dpb.fs_ref[i]->is_long_term = 3;
          return;
        }
      }
    }
    printf ("Warning: reference frame for long term marking not found\n");
  }
  else
  {
    if (p->structure == TOP_FIELD)
    {
      add_top    = 1;
      add_bottom = 0;
    }
    else
    {
      add_top    = 0;
      add_bottom = 1;
    }
    for (i=0; i<dpb.ref_frames_in_buffer; i++)
    {
      if (dpb.fs_ref[i]->is_reference & 1)
      {
        if ((!dpb.fs_ref[i]->top_field->is_long_term)&&(dpb.fs_ref[i]->top_field->pic_num == picNumX))
        {
          if ((dpb.fs_ref[i]->is_long_term) && (dpb.fs_ref[i]->long_term_frame_idx != long_term_frame_idx))
          {
              printf ("Warning: assigning long_term_frame_idx different from other field\n");
          }

          dpb.fs_ref[i]->long_term_frame_idx = dpb.fs_ref[i]->top_field->long_term_frame_idx 
                                             = long_term_frame_idx;
          dpb.fs_ref[i]->top_field->long_term_pic_num = 2 * long_term_frame_idx + add_top;
          dpb.fs_ref[i]->top_field->is_long_term = 1;
          dpb.fs_ref[i]->is_long_term |= 1;
          if (dpb.fs_ref[i]->is_long_term == 3)
          {
            dpb.fs_ref[i]->frame->is_long_term = 1;
            dpb.fs_ref[i]->frame->long_term_frame_idx = dpb.fs_ref[i]->frame->long_term_pic_num = long_term_frame_idx;
          }
          return;
        }
      }
      if (dpb.fs_ref[i]->is_reference & 2)
      {
        if ((!dpb.fs_ref[i]->bottom_field->is_long_term)&&(dpb.fs_ref[i]->bottom_field->pic_num == picNumX))
        {
          if ((dpb.fs_ref[i]->is_long_term) && (dpb.fs_ref[i]->long_term_frame_idx != long_term_frame_idx))
          {
              printf ("Warning: assigning long_term_frame_idx different from other field\n");
          }

          dpb.fs_ref[i]->long_term_frame_idx = dpb.fs_ref[i]->bottom_field->long_term_frame_idx 
                                             = long_term_frame_idx;
          dpb.fs_ref[i]->bottom_field->long_term_pic_num = 2 * long_term_frame_idx + add_top;
          dpb.fs_ref[i]->bottom_field->is_long_term = 1;
          dpb.fs_ref[i]->is_long_term |= 2;
          if (dpb.fs_ref[i]->is_long_term == 3)
          {
            dpb.fs_ref[i]->frame->is_long_term = 1;
            dpb.fs_ref[i]->frame->long_term_frame_idx = dpb.fs_ref[i]->frame->long_term_pic_num = long_term_frame_idx;
          }
          return;
        }
      }
    }
    printf ("Warning: reference field for long term marking not found\n");
  }
}


/*!
 ************************************************************************
 * \brief
 *    Assign a long term frame index to a short term picture
 ************************************************************************
 */
static void mm_assign_long_term_frame_idx(StorablePicture* p, int difference_of_pic_nums_minus1, int long_term_frame_idx)
{
  int picNumX;

  picNumX = get_pic_num_x(p, difference_of_pic_nums_minus1);

  // remove frames/fields with same long_term_frame_idx
  if (p->structure == FRAME)
  {
    unmark_long_term_frame_for_reference_by_frame_idx(long_term_frame_idx);
  }
  else
  {
    unmark_long_term_field_for_reference_by_frame_idx(p, long_term_frame_idx, picNumX);
  }

  mark_pic_long_term(p, long_term_frame_idx, picNumX);
}

/*!
 ************************************************************************
 * \brief
 *    Set new max long_term_frame_idx
 ************************************************************************
 */
void mm_update_max_long_term_frame_idx(int max_long_term_frame_idx_plus1)
{
  unsigned i;

  dpb.max_long_term_pic_idx = max_long_term_frame_idx_plus1 - 1;

  // check for invalid frames
  for (i=0; i<dpb.ltref_frames_in_buffer; i++)
  {
    if (dpb.fs_ltref[i]->long_term_frame_idx > dpb.max_long_term_pic_idx)
    {
      unmark_for_long_term_reference(dpb.fs_ltref[i]);
    }
  }
}


/*!
 ************************************************************************
 * \brief
 *    Mark all long term reference pictures unused for reference
 ************************************************************************
 */
static void mm_unmark_all_long_term_for_reference ()
{
  mm_update_max_long_term_frame_idx(0);
}

/*!
 ************************************************************************
 * \brief
 *    Mark all short term reference pictures unused for reference
 ************************************************************************
 */
static void mm_unmark_all_short_term_for_reference ()
{
  unsigned int i;
  for (i=0; i<dpb.ref_frames_in_buffer; i++)
  {
    unmark_for_reference(dpb.fs_ref[i]);
  }
  update_ref_list();
}


/*!
 ************************************************************************
 * \brief
 *    Mark the current picture used for long term reference
 ************************************************************************
 */
static void mm_mark_current_picture_long_term(StorablePicture *p, int long_term_frame_idx)
{
  // remove long term pictures with same long_term_frame_idx
  if (p->structure == FRAME)
  {
    unmark_long_term_frame_for_reference_by_frame_idx(long_term_frame_idx);
  }
  else
  {
    unmark_long_term_field_for_reference_by_frame_idx(p, long_term_frame_idx, 2 * p->pic_num + 1);
  }

  p->is_long_term = 1;
  p->long_term_frame_idx = long_term_frame_idx;