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      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.   */
     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 
    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 
    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 
    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