1
2/*
3 *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
4 *
5 *  Use of this source code is governed by a BSD-style license
6 *  that can be found in the LICENSE file in the root of the source
7 *  tree. An additional intellectual property rights grant can be found
8 *  in the file PATENTS.  All contributing project authors may
9 *  be found in the AUTHORS file in the root of the source tree.
10 */
11
12#include "vp9/common/vp9_mvref_common.h"
13
14// This function searches the neighbourhood of a given MB/SB
15// to try and find candidate reference vectors.
16static void find_mv_refs_idx(const VP9_COMMON *cm, const MACROBLOCKD *xd,
17                             const TileInfo *const tile,
18                             MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
19                             int_mv *mv_ref_list,
20                             int block, int mi_row, int mi_col) {
21  const int *ref_sign_bias = cm->ref_frame_sign_bias;
22  int i, refmv_count = 0;
23  const MODE_INFO *prev_mi = !cm->error_resilient_mode && cm->prev_mi
24        ? cm->prev_mi[mi_row * xd->mi_stride + mi_col].src_mi
25        : NULL;
26  const MB_MODE_INFO *const prev_mbmi = prev_mi ? &prev_mi->src_mi->mbmi : NULL;
27
28
29  const POSITION *const mv_ref_search = mv_ref_blocks[mi->mbmi.sb_type];
30
31  int different_ref_found = 0;
32  int context_counter = 0;
33
34  // Blank the reference vector list
35  vpx_memset(mv_ref_list, 0, sizeof(*mv_ref_list) * MAX_MV_REF_CANDIDATES);
36
37  // The nearest 2 blocks are treated differently
38  // if the size < 8x8 we get the mv from the bmi substructure,
39  // and we also need to keep a mode count.
40  for (i = 0; i < 2; ++i) {
41    const POSITION *const mv_ref = &mv_ref_search[i];
42    if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
43      const MODE_INFO *const candidate_mi = xd->mi[mv_ref->col + mv_ref->row *
44                                                   xd->mi_stride].src_mi;
45      const MB_MODE_INFO *const candidate = &candidate_mi->mbmi;
46      // Keep counts for entropy encoding.
47      context_counter += mode_2_counter[candidate->mode];
48      different_ref_found = 1;
49
50      if (candidate->ref_frame[0] == ref_frame)
51        ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 0, mv_ref->col, block));
52      else if (candidate->ref_frame[1] == ref_frame)
53        ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 1, mv_ref->col, block));
54    }
55  }
56
57  // Check the rest of the neighbors in much the same way
58  // as before except we don't need to keep track of sub blocks or
59  // mode counts.
60  for (; i < MVREF_NEIGHBOURS; ++i) {
61    const POSITION *const mv_ref = &mv_ref_search[i];
62    if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
63      const MB_MODE_INFO *const candidate = &xd->mi[mv_ref->col + mv_ref->row *
64                                                    xd->mi_stride].src_mi->mbmi;
65      different_ref_found = 1;
66
67      if (candidate->ref_frame[0] == ref_frame)
68        ADD_MV_REF_LIST(candidate->mv[0]);
69      else if (candidate->ref_frame[1] == ref_frame)
70        ADD_MV_REF_LIST(candidate->mv[1]);
71    }
72  }
73
74  // Check the last frame's mode and mv info.
75  if (prev_mbmi) {
76    if (prev_mbmi->ref_frame[0] == ref_frame)
77      ADD_MV_REF_LIST(prev_mbmi->mv[0]);
78    else if (prev_mbmi->ref_frame[1] == ref_frame)
79      ADD_MV_REF_LIST(prev_mbmi->mv[1]);
80  }
81
82  // Since we couldn't find 2 mvs from the same reference frame
83  // go back through the neighbors and find motion vectors from
84  // different reference frames.
85  if (different_ref_found) {
86    for (i = 0; i < MVREF_NEIGHBOURS; ++i) {
87      const POSITION *mv_ref = &mv_ref_search[i];
88      if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
89        const MB_MODE_INFO *const candidate = &xd->mi[mv_ref->col + mv_ref->row
90                                              * xd->mi_stride].src_mi->mbmi;
91
92        // If the candidate is INTRA we don't want to consider its mv.
93        IF_DIFF_REF_FRAME_ADD_MV(candidate);
94      }
95    }
96  }
97
98  // Since we still don't have a candidate we'll try the last frame.
99  if (prev_mbmi)
100    IF_DIFF_REF_FRAME_ADD_MV(prev_mbmi);
101
102 Done:
103
104  mi->mbmi.mode_context[ref_frame] = counter_to_context[context_counter];
105
106  // Clamp vectors
107  for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i)
108    clamp_mv_ref(&mv_ref_list[i].as_mv, xd);
109}
110
111void vp9_find_mv_refs(const VP9_COMMON *cm, const MACROBLOCKD *xd,
112                                    const TileInfo *const tile,
113                                    MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
114                                    int_mv *mv_ref_list,
115                                    int mi_row, int mi_col) {
116  find_mv_refs_idx(cm, xd, tile, mi, ref_frame, mv_ref_list, -1,
117                   mi_row, mi_col);
118}
119
120static void lower_mv_precision(MV *mv, int allow_hp) {
121  const int use_hp = allow_hp && vp9_use_mv_hp(mv);
122  if (!use_hp) {
123    if (mv->row & 1)
124      mv->row += (mv->row > 0 ? -1 : 1);
125    if (mv->col & 1)
126      mv->col += (mv->col > 0 ? -1 : 1);
127  }
128}
129
130
131void vp9_find_best_ref_mvs(MACROBLOCKD *xd, int allow_hp,
132                           int_mv *mvlist, int_mv *nearest, int_mv *near) {
133  int i;
134  // Make sure all the candidates are properly clamped etc
135  for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
136    lower_mv_precision(&mvlist[i].as_mv, allow_hp);
137    clamp_mv2(&mvlist[i].as_mv, xd);
138  }
139  *nearest = mvlist[0];
140  *near = mvlist[1];
141}
142
143void vp9_append_sub8x8_mvs_for_idx(VP9_COMMON *cm, MACROBLOCKD *xd,
144                                   const TileInfo *const tile,
145                                   int block, int ref, int mi_row, int mi_col,
146                                   int_mv *nearest, int_mv *near) {
147  int_mv mv_list[MAX_MV_REF_CANDIDATES];
148  MODE_INFO *const mi = xd->mi[0].src_mi;
149  b_mode_info *bmi = mi->bmi;
150  int n;
151
152  assert(MAX_MV_REF_CANDIDATES == 2);
153
154  find_mv_refs_idx(cm, xd, tile, mi, mi->mbmi.ref_frame[ref], mv_list, block,
155                   mi_row, mi_col);
156
157  near->as_int = 0;
158  switch (block) {
159    case 0:
160      nearest->as_int = mv_list[0].as_int;
161      near->as_int = mv_list[1].as_int;
162      break;
163    case 1:
164    case 2:
165      nearest->as_int = bmi[0].as_mv[ref].as_int;
166      for (n = 0; n < MAX_MV_REF_CANDIDATES; ++n)
167        if (nearest->as_int != mv_list[n].as_int) {
168          near->as_int = mv_list[n].as_int;
169          break;
170        }
171      break;
172    case 3: {
173      int_mv candidates[2 + MAX_MV_REF_CANDIDATES];
174      candidates[0] = bmi[1].as_mv[ref];
175      candidates[1] = bmi[0].as_mv[ref];
176      candidates[2] = mv_list[0];
177      candidates[3] = mv_list[1];
178
179      nearest->as_int = bmi[2].as_mv[ref].as_int;
180      for (n = 0; n < 2 + MAX_MV_REF_CANDIDATES; ++n)
181        if (nearest->as_int != candidates[n].as_int) {
182          near->as_int = candidates[n].as_int;
183          break;
184        }
185      break;
186    }
187    default:
188      assert("Invalid block index.");
189  }
190}
191