1 /*
2  *  Copyright (c) 2010 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 
12 #include "findnearmv.h"
13 
14 const unsigned char vp8_mbsplit_offset[4][16] = {
15     { 0,  8,  0,  0,  0,  0,  0,  0,  0,  0,   0,  0,  0,  0,  0,  0},
16     { 0,  2,  0,  0,  0,  0,  0,  0,  0,  0,   0,  0,  0,  0,  0,  0},
17     { 0,  2,  8, 10,  0,  0,  0,  0,  0,  0,   0,  0,  0,  0,  0,  0},
18     { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15}
19 };
20 
21 /* Predict motion vectors using those from already-decoded nearby blocks.
22    Note that we only consider one 4x4 subblock from each candidate 16x16
23    macroblock.   */
vp8_find_near_mvs(MACROBLOCKD * xd,const MODE_INFO * here,int_mv * nearest,int_mv * nearby,int_mv * best_mv,int cnt[4],int refframe,int * ref_frame_sign_bias)24 void vp8_find_near_mvs
25 (
26     MACROBLOCKD *xd,
27     const MODE_INFO *here,
28     int_mv *nearest,
29     int_mv *nearby,
30     int_mv *best_mv,
31     int cnt[4],
32     int refframe,
33     int *ref_frame_sign_bias
34 )
35 {
36     const MODE_INFO *above = here - xd->mode_info_stride;
37     const MODE_INFO *left = here - 1;
38     const MODE_INFO *aboveleft = above - 1;
39     int_mv            near_mvs[4];
40     int_mv           *mv = near_mvs;
41     int             *cntx = cnt;
42     enum {CNT_INTRA, CNT_NEAREST, CNT_NEAR, CNT_SPLITMV};
43 
44     /* Zero accumulators */
45     mv[0].as_int = mv[1].as_int = mv[2].as_int = 0;
46     cnt[0] = cnt[1] = cnt[2] = cnt[3] = 0;
47 
48     /* Process above */
49     if (above->mbmi.ref_frame != INTRA_FRAME)
50     {
51         if (above->mbmi.mv.as_int)
52         {
53             (++mv)->as_int = above->mbmi.mv.as_int;
54             mv_bias(ref_frame_sign_bias[above->mbmi.ref_frame], refframe, mv, ref_frame_sign_bias);
55             ++cntx;
56         }
57 
58         *cntx += 2;
59     }
60 
61     /* Process left */
62     if (left->mbmi.ref_frame != INTRA_FRAME)
63     {
64         if (left->mbmi.mv.as_int)
65         {
66             int_mv this_mv;
67 
68             this_mv.as_int = left->mbmi.mv.as_int;
69             mv_bias(ref_frame_sign_bias[left->mbmi.ref_frame], refframe, &this_mv, ref_frame_sign_bias);
70 
71             if (this_mv.as_int != mv->as_int)
72             {
73                 (++mv)->as_int = this_mv.as_int;
74                 ++cntx;
75             }
76 
77             *cntx += 2;
78         }
79         else
80             cnt[CNT_INTRA] += 2;
81     }
82 
83     /* Process above left */
84     if (aboveleft->mbmi.ref_frame != INTRA_FRAME)
85     {
86         if (aboveleft->mbmi.mv.as_int)
87         {
88             int_mv this_mv;
89 
90             this_mv.as_int = aboveleft->mbmi.mv.as_int;
91             mv_bias(ref_frame_sign_bias[aboveleft->mbmi.ref_frame], refframe, &this_mv, ref_frame_sign_bias);
92 
93             if (this_mv.as_int != mv->as_int)
94             {
95                 (++mv)->as_int = this_mv.as_int;
96                 ++cntx;
97             }
98 
99             *cntx += 1;
100         }
101         else
102             cnt[CNT_INTRA] += 1;
103     }
104 
105     /* If we have three distinct MV's ... */
106     if (cnt[CNT_SPLITMV])
107     {
108         /* See if above-left MV can be merged with NEAREST */
109         if (mv->as_int == near_mvs[CNT_NEAREST].as_int)
110             cnt[CNT_NEAREST] += 1;
111     }
112 
113     cnt[CNT_SPLITMV] = ((above->mbmi.mode == SPLITMV)
114                         + (left->mbmi.mode == SPLITMV)) * 2
115                        + (aboveleft->mbmi.mode == SPLITMV);
116 
117     /* Swap near and nearest if necessary */
118     if (cnt[CNT_NEAR] > cnt[CNT_NEAREST])
119     {
120         int tmp;
121         tmp = cnt[CNT_NEAREST];
122         cnt[CNT_NEAREST] = cnt[CNT_NEAR];
123         cnt[CNT_NEAR] = tmp;
124         tmp = near_mvs[CNT_NEAREST].as_int;
125         near_mvs[CNT_NEAREST].as_int = near_mvs[CNT_NEAR].as_int;
126         near_mvs[CNT_NEAR].as_int = tmp;
127     }
128 
129     /* Use near_mvs[0] to store the "best" MV */
130     if (cnt[CNT_NEAREST] >= cnt[CNT_INTRA])
131         near_mvs[CNT_INTRA] = near_mvs[CNT_NEAREST];
132 
133     /* Set up return values */
134     best_mv->as_int = near_mvs[0].as_int;
135     nearest->as_int = near_mvs[CNT_NEAREST].as_int;
136     nearby->as_int = near_mvs[CNT_NEAR].as_int;
137 }
138 
139 
invert_and_clamp_mvs(int_mv * inv,int_mv * src,MACROBLOCKD * xd)140 static void invert_and_clamp_mvs(int_mv *inv, int_mv *src, MACROBLOCKD *xd)
141 {
142     inv->as_mv.row = src->as_mv.row * -1;
143     inv->as_mv.col = src->as_mv.col * -1;
144     vp8_clamp_mv2(inv, xd);
145     vp8_clamp_mv2(src, xd);
146 }
147 
148 
vp8_find_near_mvs_bias(MACROBLOCKD * xd,const MODE_INFO * here,int_mv mode_mv_sb[2][MB_MODE_COUNT],int_mv best_mv_sb[2],int cnt[4],int refframe,int * ref_frame_sign_bias)149 int vp8_find_near_mvs_bias
150 (
151     MACROBLOCKD *xd,
152     const MODE_INFO *here,
153     int_mv mode_mv_sb[2][MB_MODE_COUNT],
154     int_mv best_mv_sb[2],
155     int cnt[4],
156     int refframe,
157     int *ref_frame_sign_bias
158 )
159 {
160     int sign_bias = ref_frame_sign_bias[refframe];
161 
162     vp8_find_near_mvs(xd,
163                       here,
164                       &mode_mv_sb[sign_bias][NEARESTMV],
165                       &mode_mv_sb[sign_bias][NEARMV],
166                       &best_mv_sb[sign_bias],
167                       cnt,
168                       refframe,
169                       ref_frame_sign_bias);
170 
171     invert_and_clamp_mvs(&mode_mv_sb[!sign_bias][NEARESTMV],
172                          &mode_mv_sb[sign_bias][NEARESTMV], xd);
173     invert_and_clamp_mvs(&mode_mv_sb[!sign_bias][NEARMV],
174                          &mode_mv_sb[sign_bias][NEARMV], xd);
175     invert_and_clamp_mvs(&best_mv_sb[!sign_bias],
176                          &best_mv_sb[sign_bias], xd);
177 
178     return sign_bias;
179 }
180 
181 
vp8_mv_ref_probs(vp8_prob p[VP8_MVREFS-1],const int near_mv_ref_ct[4])182 vp8_prob *vp8_mv_ref_probs(
183     vp8_prob p[VP8_MVREFS-1], const int near_mv_ref_ct[4]
184 )
185 {
186     p[0] = vp8_mode_contexts [near_mv_ref_ct[0]] [0];
187     p[1] = vp8_mode_contexts [near_mv_ref_ct[1]] [1];
188     p[2] = vp8_mode_contexts [near_mv_ref_ct[2]] [2];
189     p[3] = vp8_mode_contexts [near_mv_ref_ct[3]] [3];
190     /*p[3] = vp8_mode_contexts [near_mv_ref_ct[1] + near_mv_ref_ct[2] + near_mv_ref_ct[3]] [3];*/
191     return p;
192 }
193 
194