vp8/common/findnearmv.c

   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     //TODO: move clamp outside findnearmv
 139     vp8_clamp_mv2(nearest, xd);
 140     vp8_clamp_mv2(nearby, xd);
 141     vp8_clamp_mv2(best_mv, xd);
 142 }
 143
 144 vp8_prob *vp8_mv_ref_probs(
 145     vp8_prob p[VP8_MVREFS-1], const int near_mv_ref_ct[4]
 146 )
 147 {
 148     p[0] = vp8_mode_contexts [near_mv_ref_ct[0]] [0];
 149     p[1] = vp8_mode_contexts [near_mv_ref_ct[1]] [1];
 150     p[2] = vp8_mode_contexts [near_mv_ref_ct[2]] [2];
 151     p[3] = vp8_mode_contexts [near_mv_ref_ct[3]] [3];
 152     /*p[3] = vp8_mode_contexts [near_mv_ref_ct[1] + near_mv_ref_ct[2] + near_mv_ref_ct[3]] [3];*/
 153     return p;
 154 }
 155