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      1 /*
      2  *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "vp9/common/vp9_blockd.h"
     12 
     13 PREDICTION_MODE vp9_left_block_mode(const MODE_INFO *cur_mi,
     14                                     const MODE_INFO *left_mi, int b) {
     15   if (b == 0 || b == 2) {
     16     if (!left_mi || is_inter_block(left_mi)) return DC_PRED;
     17 
     18     return get_y_mode(left_mi, b + 1);
     19   } else {
     20     assert(b == 1 || b == 3);
     21     return cur_mi->bmi[b - 1].as_mode;
     22   }
     23 }
     24 
     25 PREDICTION_MODE vp9_above_block_mode(const MODE_INFO *cur_mi,
     26                                      const MODE_INFO *above_mi, int b) {
     27   if (b == 0 || b == 1) {
     28     if (!above_mi || is_inter_block(above_mi)) return DC_PRED;
     29 
     30     return get_y_mode(above_mi, b + 2);
     31   } else {
     32     assert(b == 2 || b == 3);
     33     return cur_mi->bmi[b - 2].as_mode;
     34   }
     35 }
     36 
     37 void vp9_foreach_transformed_block_in_plane(
     38     const MACROBLOCKD *const xd, BLOCK_SIZE bsize, int plane,
     39     foreach_transformed_block_visitor visit, void *arg) {
     40   const struct macroblockd_plane *const pd = &xd->plane[plane];
     41   const MODE_INFO *mi = xd->mi[0];
     42   // block and transform sizes, in number of 4x4 blocks log 2 ("*_b")
     43   // 4x4=0, 8x8=2, 16x16=4, 32x32=6, 64x64=8
     44   // transform size varies per plane, look it up in a common way.
     45   const TX_SIZE tx_size = plane ? get_uv_tx_size(mi, pd) : mi->tx_size;
     46   const BLOCK_SIZE plane_bsize = get_plane_block_size(bsize, pd);
     47   const int num_4x4_w = num_4x4_blocks_wide_lookup[plane_bsize];
     48   const int num_4x4_h = num_4x4_blocks_high_lookup[plane_bsize];
     49   const int step = 1 << (tx_size << 1);
     50   int i = 0, r, c;
     51 
     52   // If mb_to_right_edge is < 0 we are in a situation in which
     53   // the current block size extends into the UMV and we won't
     54   // visit the sub blocks that are wholly within the UMV.
     55   const int max_blocks_wide =
     56       num_4x4_w + (xd->mb_to_right_edge >= 0
     57                        ? 0
     58                        : xd->mb_to_right_edge >> (5 + pd->subsampling_x));
     59   const int max_blocks_high =
     60       num_4x4_h + (xd->mb_to_bottom_edge >= 0
     61                        ? 0
     62                        : xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
     63   const int extra_step = ((num_4x4_w - max_blocks_wide) >> tx_size) * step;
     64 
     65   // Keep track of the row and column of the blocks we use so that we know
     66   // if we are in the unrestricted motion border.
     67   for (r = 0; r < max_blocks_high; r += (1 << tx_size)) {
     68     // Skip visiting the sub blocks that are wholly within the UMV.
     69     for (c = 0; c < max_blocks_wide; c += (1 << tx_size)) {
     70       visit(plane, i, r, c, plane_bsize, tx_size, arg);
     71       i += step;
     72     }
     73     i += extra_step;
     74   }
     75 }
     76 
     77 void vp9_foreach_transformed_block(const MACROBLOCKD *const xd,
     78                                    BLOCK_SIZE bsize,
     79                                    foreach_transformed_block_visitor visit,
     80                                    void *arg) {
     81   int plane;
     82 
     83   for (plane = 0; plane < MAX_MB_PLANE; ++plane)
     84     vp9_foreach_transformed_block_in_plane(xd, bsize, plane, visit, arg);
     85 }
     86 
     87 void vp9_set_contexts(const MACROBLOCKD *xd, struct macroblockd_plane *pd,
     88                       BLOCK_SIZE plane_bsize, TX_SIZE tx_size, int has_eob,
     89                       int aoff, int loff) {
     90   ENTROPY_CONTEXT *const a = pd->above_context + aoff;
     91   ENTROPY_CONTEXT *const l = pd->left_context + loff;
     92   const int tx_size_in_blocks = 1 << tx_size;
     93 
     94   // above
     95   if (has_eob && xd->mb_to_right_edge < 0) {
     96     int i;
     97     const int blocks_wide = num_4x4_blocks_wide_lookup[plane_bsize] +
     98                             (xd->mb_to_right_edge >> (5 + pd->subsampling_x));
     99     int above_contexts = tx_size_in_blocks;
    100     if (above_contexts + aoff > blocks_wide)
    101       above_contexts = blocks_wide - aoff;
    102 
    103     for (i = 0; i < above_contexts; ++i) a[i] = has_eob;
    104     for (i = above_contexts; i < tx_size_in_blocks; ++i) a[i] = 0;
    105   } else {
    106     memset(a, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
    107   }
    108 
    109   // left
    110   if (has_eob && xd->mb_to_bottom_edge < 0) {
    111     int i;
    112     const int blocks_high = num_4x4_blocks_high_lookup[plane_bsize] +
    113                             (xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
    114     int left_contexts = tx_size_in_blocks;
    115     if (left_contexts + loff > blocks_high) left_contexts = blocks_high - loff;
    116 
    117     for (i = 0; i < left_contexts; ++i) l[i] = has_eob;
    118     for (i = left_contexts; i < tx_size_in_blocks; ++i) l[i] = 0;
    119   } else {
    120     memset(l, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
    121   }
    122 }
    123 
    124 void vp9_setup_block_planes(MACROBLOCKD *xd, int ss_x, int ss_y) {
    125   int i;
    126 
    127   for (i = 0; i < MAX_MB_PLANE; i++) {
    128     xd->plane[i].subsampling_x = i ? ss_x : 0;
    129     xd->plane[i].subsampling_y = i ? ss_y : 0;
    130   }
    131 }
    132