text: /*
   *  Copyright (c) 2011 The WebM project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #include "error_concealment.h"
  #include "onyxd_int.h"
  #include "decodemv.h"
  #include "vpx_mem/vpx_mem.h"
  #include "vp8/common/recon.h"
  #include "vp8/common/findnearmv.h"
  
  #include <assert.h>
  
  #define MIN(x,y) (((x)<(y))?(x):(y))
  #define MAX(x,y) (((x)>(y))?(x):(y))
  
  #define FLOOR(x,q) ((x) & -(1 << (q)))
  
  #define NUM_NEIGHBORS 20
  
  typedef struct ec_position
  {
      int row;
      int col;
  } EC_POS;
  
  /*
   * Regenerate the table in Matlab with:
   * x = meshgrid((1:4), (1:4));
   * y = meshgrid((1:4), (1:4))';
   * W = round((1./(sqrt(x.^2 + y.^2))*2^7));
   * W(1,1) = 0;
   */
  static const int weights_q7[5][5] = {
         {  0,   128,    64,    43,    32 },
         {128,    91,    57,    40,    31 },
         { 64,    57,    45,    36,    29 },
         { 43,    40,    36,    30,    26 },
         { 32,    31,    29,    26,    23 }
  };
  
  int vp8_alloc_overlap_lists(VP8D_COMP *pbi)
  {
      if (pbi->overlaps != NULL)
      {
          vpx_free(pbi->overlaps);
          pbi->overlaps = NULL;
      }
      pbi->overlaps = vpx_calloc(pbi->common.mb_rows * pbi->common.mb_cols,
                                 sizeof(MB_OVERLAP));
      if (pbi->overlaps == NULL)
          return -1;
      vpx_memset(pbi->overlaps, 0,
                 sizeof(MB_OVERLAP) * pbi->common.mb_rows * pbi->common.mb_cols);
      return 0;
  }
  
  void vp8_de_alloc_overlap_lists(VP8D_COMP *pbi)
  {
      vpx_free(pbi->overlaps);
      pbi->overlaps = NULL;
  }
  
  /* Inserts a new overlap area value to the list of overlaps of a block */
  static void assign_overlap(OVERLAP_NODE* overlaps,
                             union b_mode_info *bmi,
                             int overlap)
  {
      int i;
      if (overlap <= 0)
          return;
      /* Find and assign to the next empty overlap node in the list of overlaps.
       * Empty is defined as bmi == NULL */
      for (i = 0; i < MAX_OVERLAPS; i++)
      {
          if (overlaps[i].bmi == NULL)
          {
              overlaps[i].bmi = bmi;
              overlaps[i].overlap = overlap;
              break;
          }
      }
  }
  
  /* Calculates the overlap area between two 4x4 squares, where the first
   * square has its upper-left corner at (b1_row, b1_col) and the second
   * square has its upper-left corner at (b2_row, b2_col). Doesn't
   * properly handle squares which do not overlap.
   */
  static int block_overlap(int b1_row, int b1_col, int b2_row, int b2_col)
  {
      const int int_top = MAX(b1_row, b2_row); // top
      const int int_left = MAX(b1_col, b2_col); // left
      /* Since each block is 4x4 pixels, adding 4 (Q3) to the left/top edge
       * gives us the right/bottom edge.
       */
      const int int_right = MIN(b1_col + (4<<3), b2_col + (4<<3)); // right
      const int int_bottom = MIN(b1_row + (4<<3), b2_row + (4<<3)); // bottom
      return (int_bottom - int_top) * (int_right - int_left);
  }
  
  /* Calculates the overlap area for all blocks in a macroblock at position
   * (mb_row, mb_col) in macroblocks, which are being overlapped by a given
   * overlapping block at position (new_row, new_col) (in pixels, Q3). The
   * first block being overlapped in the macroblock has position (first_blk_row,
   * first_blk_col) in blocks relative the upper-left corner of the image.
   */
  static void calculate_overlaps_mb(B_OVERLAP *b_overlaps, union b_mode_info *bmi,
                                    int new_row, int new_col,
                                    int mb_row, int mb_col,
                                    int first_blk_row, int first_blk_col)
  {
      /* Find the blocks within this MB (defined by mb_row, mb_col) which are
       * overlapped by bmi and calculate and assign overlap for each of those
       * blocks. */
  
      /* Block coordinates relative the upper-left block */
      const int rel_ol_blk_row = first_blk_row - mb_row * 4;
      const int rel_ol_blk_col = first_blk_col - mb_col * 4;
      /* If the block partly overlaps any previous MB, these coordinates
       * can be < 0. We don't want to access blocks in previous MBs.
       */
      const int blk_idx = MAX(rel_ol_blk_row,0) * 4 + MAX(rel_ol_blk_col,0);
      /* Upper left overlapping block */
      B_OVERLAP *b_ol_ul = &(b_overlaps[blk_idx]);
  
      /* Calculate and assign overlaps for all blocks in this MB
       * which the motion compensated block overlaps
       */
      /* Avoid calculating overlaps for blocks in later MBs */
      int end_row = MIN(4 + mb_row * 4 - first_blk_row, 2);
      int end_col = MIN(4 + mb_col * 4 - first_blk_col, 2);
      int row, col;
  
      /* Check if new_row and new_col are evenly divisible by 4 (Q3),
       * and if so we shouldn't check neighboring blocks
       */
      if (new_row >= 0 && (new_row & 0x1F) == 0)
          end_row = 1;
      if (new_col >= 0 && (new_col & 0x1F) == 0)
          end_col = 1;
  
      /* Check if the overlapping block partly overlaps a previous MB
       * and if so, we're overlapping fewer blocks in this MB.
       */
      if (new_row < (mb_row*16)<<3)
          end_row = 1;
      if (new_col < (mb_col*16)<<3)
          end_col = 1;
  
      for (row = 0; row < end_row; ++row)
      {
          for (col = 0; col < end_col; ++col)
          {
              /* input in Q3, result in Q6 */
              const int overlap = block_overlap(new_row, new_col,
                                                    (((first_blk_row + row) *
                                                        4) << 3),
                                                    (((first_blk_col + col) *
                                                        4) << 3));
              assign_overlap(b_ol_ul[row * 4 + col].overlaps, bmi, overlap);
          }
      }
  }
  
  void vp8_calculate_overlaps(MB_OVERLAP *overlap_ul,
                              int mb_rows, int mb_cols,
                              union b_mode_info *bmi,
                              int b_row, int b_col)
  {
      MB_OVERLAP *mb_overlap;
      int row, col, rel_row, rel_col;
      int new_row, new_col;
      int end_row, end_col;
      int overlap_b_row, overlap_b_col;
      int overlap_mb_row, overlap_mb_col;
  
      /* mb subpixel position */
      row = (4 * b_row) << 3; /* Q3 */
      col = (4 * b_col) << 3; /* Q3 */
  
      /* reverse compensate for motion */
      new_row = row - bmi->mv.as_mv.row;
      new_col = col - bmi->mv.as_mv.col;
  
      if (new_row >= ((16*mb_rows) << 3) || new_col >= ((16*mb_cols) << 3))
      {
          /* the new block ended up outside the frame */
          return;
      }
  
      if (new_row <= (-4 << 3) || new_col <= (-4 << 3))
      {
          /* outside the frame */
          return;
      }
      /* overlapping block's position in blocks */
      overlap_b_row = FLOOR(new_row / 4, 3) >> 3;
      overlap_b_col = FLOOR(new_col / 4, 3) >> 3;
  
      /* overlapping block's MB position in MBs
       * operations are done in Q3
       */
      overlap_mb_row = FLOOR((overlap_b_row << 3) / 4, 3) >> 3;
      overlap_mb_col = FLOOR((overlap_b_col << 3) / 4, 3) >> 3;
  
      end_row = MIN(mb_rows - overlap_mb_row, 2);
      end_col = MIN(mb_cols - overlap_mb_col, 2);
  
      /* Don't calculate overlap for MBs we don't overlap */
      /* Check if the new block row starts at the last block row of the MB */
      if (abs(new_row - ((16*overlap_mb_row) << 3)) < ((3*4) << 3))
          end_row = 1;
      /* Check if the new block col starts at the last block col of the MB */
      if (abs(new_col - ((16*overlap_mb_col) << 3)) < ((3*4) << 3))
          end_col = 1;
  
      /* find the MB(s) this block is overlapping */
      for (rel_row = 0; rel_row < end_row; ++rel_row)
      {
          for (rel_col = 0; rel_col < end_col; ++rel_col)
          {
              if (overlap_mb_row + rel_row < 0 ||
                  overlap_mb_col + rel_col < 0)
                  continue;
              mb_overlap = overlap_ul + (overlap_mb_row + rel_row) * mb_cols +
                   overlap_mb_col + rel_col;
  
              calculate_overlaps_mb(mb_overlap->overlaps, bmi,
                                    new_row, new_col,
                                    overlap_mb_row + rel_row,
                                    overlap_mb_col + rel_col,
                                    overlap_b_row + rel_row,
                                    overlap_b_col + rel_col);
          }
      }
  }
  
  /* Estimates a motion vector given the overlapping blocks' motion vectors.
   * Filters out all overlapping blocks which do not refer to the correct
   * reference frame type.
   */
  static void estimate_mv(const OVERLAP_NODE *overlaps, union b_mode_info *bmi)
  {
      int i;
      int overlap_sum = 0;
      int row_acc = 0;
      int col_acc = 0;
  
      bmi->mv.as_int = 0;
      for (i=0; i < MAX_OVERLAPS; ++i)
      {
          if (overlaps[i].bmi == NULL)
              break;
          col_acc += overlaps[i].overlap * overlaps[i].bmi->mv.as_mv.col;
          row_acc += overlaps[i].overlap * overlaps[i].bmi->mv.as_mv.row;
          overlap_sum += overlaps[i].overlap;
      }
      if (overlap_sum > 0)
      {
          /* Q9 / Q6 = Q3 */
          bmi->mv.as_mv.col = col_acc / overlap_sum;
          bmi->mv.as_mv.row = row_acc / overlap_sum;
      }
      else
      {
          bmi->mv.as_mv.col = 0;
          bmi->mv.as_mv.row = 0;
      }
  }
  
  /* Estimates all motion vectors for a macroblock given the lists of
   * overlaps for each block. Decides whether or not the MVs must be clamped.
   */
  static void estimate_mb_mvs(const B_OVERLAP *block_overlaps,
                              MODE_INFO *mi,
                              int mb_to_left_edge,
                              int mb_to_right_edge,
                              int mb_to_top_edge,
                              int mb_to_bottom_edge)
  {
      int row, col;
      int non_zero_count = 0;
      MV * const filtered_mv = &(mi->mbmi.mv.as_mv);
      union b_mode_info * const bmi = mi->bmi;
      filtered_mv->col = 0;
      filtered_mv->row = 0;
      mi->mbmi.need_to_clamp_mvs = 0;
      for (row = 0; row < 4; ++row)
      {
          int this_b_to_top_edge = mb_to_top_edge + ((row*4)<<3);
          int this_b_to_bottom_edge = mb_to_bottom_edge - ((row*4)<<3);
          for (col = 0; col < 4; ++col)
          {
              int i = row * 4 + col;
              int this_b_to_left_edge = mb_to_left_edge + ((col*4)<<3);
              int this_b_to_right_edge = mb_to_right_edge - ((col*4)<<3);
              /* Estimate vectors for all blocks which are overlapped by this */
              /* type. Interpolate/extrapolate the rest of the block's MVs */
              estimate_mv(block_overlaps[i].overlaps, &(bmi[i]));
              mi->mbmi.need_to_clamp_mvs |= vp8_check_mv_bounds(
                                                           &bmi[i].mv,
                                                           this_b_to_left_edge,
                                                           this_b_to_right_edge,
                                                           this_b_to_top_edge,
                                                           this_b_to_bottom_edge);
              if (bmi[i].mv.as_int != 0)
              {
                  ++non_zero_count;
                  filtered_mv->col += bmi[i].mv.as_mv.col;
                  filtered_mv->row += bmi[i].mv.as_mv.row;
              }
          }
      }
      if (non_zero_count > 0)
      {
          filtered_mv->col /= non_zero_count;
          filtered_mv->row /= non_zero_count;
      }
  }
  
  static void calc_prev_mb_overlaps(MB_OVERLAP *overlaps, MODE_INFO *prev_mi,
                                      int mb_row, int mb_col,
                                      int mb_rows, int mb_cols)
  {
      int sub_row;
      int sub_col;
      for (sub_row = 0; sub_row < 4; ++sub_row)
      {
          for (sub_col = 0; sub_col < 4; ++sub_col)
          {
              vp8_calculate_overlaps(
                                  overlaps, mb_rows, mb_cols,
                                  &(prev_mi->bmi[sub_row * 4 + sub_col]),
                                  4 * mb_row + sub_row,
                                  4 * mb_col + sub_col);
          }
      }
  }
  
  /* Estimate all missing motion vectors. This function does the same as the one
   * above, but has different input arguments. */
  static void estimate_missing_mvs(MB_OVERLAP *overlaps,
                                   MODE_INFO *mi, MODE_INFO *prev_mi,
                                   int mb_rows, int mb_cols,
                                   unsigned int first_corrupt)
  {
      int mb_row, mb_col;
      vpx_memset(overlaps, 0, sizeof(MB_OVERLAP) * mb_rows * mb_cols);
      /* First calculate the overlaps for all blocks */
      for (mb_row = 0; mb_row < mb_rows; ++mb_row)
      {
          for (mb_col = 0; mb_col < mb_cols; ++mb_col)
          {
              /* We're only able to use blocks referring to the last frame
               * when extrapolating new vectors.
               */
              if (prev_mi->mbmi.ref_frame == LAST_FRAME)
              {
                  calc_prev_mb_overlaps(overlaps, prev_mi,
                                        mb_row, mb_col,
                                        mb_rows, mb_cols);
              }
              ++prev_mi;
          }
          ++prev_mi;
      }
  
      mb_row = first_corrupt / mb_cols;
      mb_col = first_corrupt - mb_row * mb_cols;
      mi += mb_row*(mb_cols + 1) + mb_col;
      /* Go through all macroblocks in the current image with missing MVs
       * and calculate new MVs using the overlaps.
       */
      for (; mb_row < mb_rows; ++mb_row)
      {
          int mb_to_top_edge = -((mb_row * 16)) << 3;
          int mb_to_bottom_edge = ((mb_rows - 1 - mb_row) * 16) << 3;
          for (; mb_col < mb_cols; ++mb_col)
          {
              int mb_to_left_edge = -((mb_col * 16) << 3);
              int mb_to_right_edge = ((mb_cols - 1 - mb_col) * 16) << 3;
              const B_OVERLAP *block_overlaps =
                      overlaps[mb_row*mb_cols + mb_col].overlaps;
              mi->mbmi.ref_frame = LAST_FRAME;
              mi->mbmi.mode = SPLITMV;
              mi->mbmi.uv_mode = DC_PRED;
              mi->mbmi.partitioning = 3;
              mi->mbmi.segment_id = 0;
              estimate_mb_mvs(block_overlaps,
                              mi,
                              mb_to_left_edge,
                              mb_to_right_edge,
                              mb_to_top_edge,
                              mb_to_bottom_edge);
              ++mi;
          }
          mb_col = 0;
          ++mi;
      }
  }
  
  void vp8_estimate_missing_mvs(VP8D_COMP *pbi)
  {
      VP8_COMMON * const pc = &pbi->common;
      estimate_missing_mvs(pbi->overlaps,
                           pc->mi, pc->prev_mi,
                           pc->mb_rows, pc->mb_cols,
                           pbi->mvs_corrupt_from_mb);
  }
  
  static void assign_neighbor(EC_BLOCK *neighbor, MODE_INFO *mi, int block_idx)
  {
      assert(mi->mbmi.ref_frame < MAX_REF_FRAMES);
      neighbor->ref_frame = mi->mbmi.ref_frame;
      neighbor->mv = mi->bmi[block_idx].mv.as_mv;
  }
  
  /* Finds the neighboring blocks of a macroblocks. In the general case
   * 20 blocks are found. If a fewer number of blocks are found due to
   * image boundaries, those positions in the EC_BLOCK array are left "empty".
   * The neighbors are enumerated with the upper-left neighbor as the first
   * element, the second element refers to the neighbor to right of the previous
   * neighbor, and so on. The last element refers to the neighbor below the first
   * neighbor.
   */
  static void find_neighboring_blocks(MODE_INFO *mi,
                                      EC_BLOCK *neighbors,
                                      int mb_row, int mb_col,
                                      int mb_rows, int mb_cols,
                                      int mi_stride)
  {
      int i = 0;
      int j;
      if (mb_row > 0)
      {
          /* upper left */
          if (mb_col > 0)
              assign_neighbor(&neighbors[i], mi - mi_stride - 1, 15);
          ++i;
          /* above */
          for (j = 12; j < 16; ++j, ++i)
              assign_neighbor(&neighbors[i], mi - mi_stride, j);
      }
      else
          i += 5;
      if (mb_col < mb_cols - 1)
      {
          /* upper right */
          if (mb_row > 0)
              assign_neighbor(&neighbors[i], mi - mi_stride + 1, 12);
          ++i;
          /* right */
          for (j = 0; j <= 12; j += 4, ++i)
              assign_neighbor(&neighbors[i], mi + 1, j);
      }
      else
          i += 5;
      if (mb_row < mb_rows - 1)
      {
          /* lower right */
          if (mb_col < mb_cols - 1)
              assign_neighbor(&neighbors[i], mi + mi_stride + 1, 0);
          ++i;
          /* below */
          for (j = 0; j < 4; ++j, ++i)
              assign_neighbor(&neighbors[i], mi + mi_stride, j);
      }
      else
          i += 5;
      if (mb_col > 0)
      {
          /* lower left */
          if (mb_row < mb_rows - 1)
              assign_neighbor(&neighbors[i], mi + mi_stride - 1, 4);
          ++i;
          /* left */
          for (j = 3; j < 16; j += 4, ++i)
          {
              assign_neighbor(&neighbors[i], mi - 1, j);
          }
      }
      else
          i += 5;
      assert(i == 20);
  }
  
  /* Interpolates all motion vectors for a macroblock from the neighboring blocks'
   * motion vectors.
   */
  static void interpolate_mvs(MACROBLOCKD *mb,
                           EC_BLOCK *neighbors,
                           MV_REFERENCE_FRAME dom_ref_frame)
  {
      int row, col, i;
      MODE_INFO * const mi = mb->mode_info_context;
      /* Table with the position of the neighboring blocks relative the position
       * of the upper left block of the current MB. Starting with the upper left
       * neighbor and going to the right.
       */
      const EC_POS neigh_pos[NUM_NEIGHBORS] = {
                                          {-1,-1}, {-1,0}, {-1,1}, {-1,2}, {-1,3},
                                          {-1,4}, {0,4}, {1,4}, {2,4}, {3,4},
                                          {4,4}, {4,3}, {4,2}, {4,1}, {4,0},
                                          {4,-1}, {3,-1}, {2,-1}, {1,-1}, {0,-1}
                                        };
      mi->mbmi.need_to_clamp_mvs = 0;
      for (row = 0; row < 4; ++row)
      {
          int mb_to_top_edge = mb->mb_to_top_edge + ((row*4)<<3);
          int mb_to_bottom_edge = mb->mb_to_bottom_edge - ((row*4)<<3);
          for (col = 0; col < 4; ++col)
          {
              int mb_to_left_edge = mb->mb_to_left_edge + ((col*4)<<3);
              int mb_to_right_edge = mb->mb_to_right_edge - ((col*4)<<3);
              int w_sum = 0;
              int mv_row_sum = 0;
              int mv_col_sum = 0;
              int_mv * const mv = &(mi->bmi[row*4 + col].mv);
              mv->as_int = 0;
              for (i = 0; i < NUM_NEIGHBORS; ++i)
              {
                  /* Calculate the weighted sum of neighboring MVs referring
                   * to the dominant frame type.
                   */
                  const int w = weights_q7[abs(row - neigh_pos[i].row)]
                                          [abs(col - neigh_pos[i].col)];
                  if (neighbors[i].ref_frame != dom_ref_frame)
                      continue;
                  w_sum += w;
                  /* Q7 * Q3 = Q10 */
                  mv_row_sum += w*neighbors[i].mv.row;
                  mv_col_sum += w*neighbors[i].mv.col;
              }
              if (w_sum > 0)
              {
                  /* Avoid division by zero.
                   * Normalize with the sum of the coefficients
                   * Q3 = Q10 / Q7
                   */
                  mv->as_mv.row = mv_row_sum / w_sum;
                  mv->as_mv.col = mv_col_sum / w_sum;
                  mi->mbmi.need_to_clamp_mvs |= vp8_check_mv_bounds(
                                                              mv,
                                                              mb_to_left_edge,
                                                              mb_to_right_edge,
                                                              mb_to_top_edge,
                                                              mb_to_bottom_edge);
              }
          }
      }
  }
  
  void vp8_interpolate_motion(MACROBLOCKD *mb,
                          int mb_row, int mb_col,
                          int mb_rows, int mb_cols,
                          int mi_stride)
  {
      /* Find relevant neighboring blocks */
      EC_BLOCK neighbors[NUM_NEIGHBORS];
      int i;
      /* Initialize the array. MAX_REF_FRAMES is interpreted as "doesn't exist" */
      for (i = 0; i < NUM_NEIGHBORS; ++i)
      {
          neighbors[i].ref_frame = MAX_REF_FRAMES;
          neighbors[i].mv.row = neighbors[i].mv.col = 0;
      }
      find_neighboring_blocks(mb->mode_info_context,
                                  neighbors,
                                  mb_row, mb_col,
                                  mb_rows, mb_cols,
                                  mb->mode_info_stride);
      /* Interpolate MVs for the missing blocks from the surrounding
       * blocks which refer to the last frame. */
      interpolate_mvs(mb, neighbors, LAST_FRAME);
  
      mb->mode_info_context->mbmi.ref_frame = LAST_FRAME;
      mb->mode_info_context->mbmi.mode = SPLITMV;
      mb->mode_info_context->mbmi.uv_mode = DC_PRED;
      mb->mode_info_context->mbmi.partitioning = 3;
      mb->mode_info_context->mbmi.segment_id = 0;
  }
  
  void vp8_conceal_corrupt_mb(MACROBLOCKD *xd)
  {
      /* This macroblock has corrupt residual, use the motion compensated
         image (predictor) for concealment */
  
      /* The build predictor functions now output directly into the dst buffer,
       * so the copies are no longer necessary */
  
  }
  