libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_reconinter.c

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 95 matching lines @@
                               mi->bmi[1].as_mv[idx].as_mv.row +
                               mi->bmi[2].as_mv[idx].as_mv.row +
                               mi->bmi[3].as_mv[idx].as_mv.row),
              round_mv_comp_q4(mi->bmi[0].as_mv[idx].as_mv.col +
                               mi->bmi[1].as_mv[idx].as_mv.col +
                               mi->bmi[2].as_mv[idx].as_mv.col +
                               mi->bmi[3].as_mv[idx].as_mv.col) };
   return res;
 }
 
+static INLINE int round_mv_comp_q2(int value) {
+  return (value < 0 ? value - 1 : value + 1) / 2;
+}
+
+static MV mi_mv_pred_q2(const MODE_INFO *mi, int idx, int block0, int block1) {
+  MV res = { round_mv_comp_q2(mi->bmi[block0].as_mv[idx].as_mv.row +
+                              mi->bmi[block1].as_mv[idx].as_mv.row),
+             round_mv_comp_q2(mi->bmi[block0].as_mv[idx].as_mv.col +
+                              mi->bmi[block1].as_mv[idx].as_mv.col) };
+  return res;
+}
+
 // TODO(jkoleszar): yet another mv clamping function :-(
 MV clamp_mv_to_umv_border_sb(const MACROBLOCKD *xd, const MV *src_mv,
                              int bw, int bh, int ss_x, int ss_y) {
   // If the MV points so far into the UMV border that no visible pixels
   // are used for reconstruction, the subpel part of the MV can be
   // discarded and the MV limited to 16 pixels with equivalent results.
   const int spel_left = (VP9_INTERP_EXTEND + bw) << SUBPEL_BITS;
   const int spel_right = spel_left - SUBPEL_SHIFTS;
   const int spel_top = (VP9_INTERP_EXTEND + bh) << SUBPEL_BITS;
   const int spel_bottom = spel_top - SUBPEL_SHIFTS;
   MV clamped_mv = {
     src_mv->row * (1 << (1 - ss_y)),
     src_mv->col * (1 << (1 - ss_x))
   };
   assert(ss_x <= 1);
   assert(ss_y <= 1);
 
   clamp_mv(&clamped_mv,
            xd->mb_to_left_edge * (1 << (1 - ss_x)) - spel_left,
            xd->mb_to_right_edge * (1 << (1 - ss_x)) + spel_right,
            xd->mb_to_top_edge * (1 << (1 - ss_y)) - spel_top,
            xd->mb_to_bottom_edge * (1 << (1 - ss_y)) + spel_bottom);
 
   return clamped_mv;
 }
 
+static MV average_split_mvs(const struct macroblockd_plane *pd, int plane,
+                            const MODE_INFO *mi, int ref, int block) {
+  const int ss_idx = ((pd->subsampling_x > 0) << 1) | (pd->subsampling_y > 0);
+  MV res = {0, 0};
+  switch (ss_idx) {
+    case 0:
+      res = mi->bmi[block].as_mv[ref].as_mv;
+      break;
+    case 1:
+      res = mi_mv_pred_q2(mi, ref, block, block + 2);
+      break;
+    case 2:
+      res = mi_mv_pred_q2(mi, ref, block, block + 1);
+      break;
+    case 3:
+      res = mi_mv_pred_q4(mi, ref);
+      break;
+    default:
+      assert(ss_idx <= 3 || ss_idx >= 0);
+  }
+  return res;
+}
+
 static void build_inter_predictors(MACROBLOCKD *xd, int plane, int block,
                                    int bw, int bh,
                                    int x, int y, int w, int h,
                                    int mi_x, int mi_y) {
   struct macroblockd_plane *const pd = &xd->plane[plane];
   const MODE_INFO *mi = xd->mi[0];
   const int is_compound = has_second_ref(&mi->mbmi);
   const InterpKernel *kernel = vp9_get_interp_kernel(mi->mbmi.interp_filter);
   int ref;
 
   for (ref = 0; ref < 1 + is_compound; ++ref) {
     const struct scale_factors *const sf = &xd->block_refs[ref]->sf;
     struct buf_2d *const pre_buf = &pd->pre[ref];
     struct buf_2d *const dst_buf = &pd->dst;
     uint8_t *const dst = dst_buf->buf + dst_buf->stride * y + x;
-
-    // TODO(jkoleszar): All chroma MVs in SPLITMV mode are taken as the
-    // same MV (the average of the 4 luma MVs) but we could do something
-    // smarter for non-4:2:0. Just punt for now, pending the changes to get
-    // rid of SPLITMV mode entirely.
     const MV mv = mi->mbmi.sb_type < BLOCK_8X8
-               ? (plane == 0 ? mi->bmi[block].as_mv[ref].as_mv
-                             : mi_mv_pred_q4(mi, ref))
+               ? average_split_mvs(pd, plane, mi, ref, block)
                : mi->mbmi.mv[ref].as_mv;
 
     // TODO(jkoleszar): This clamping is done in the incorrect place for the
     // scaling case. It needs to be done on the scaled MV, not the pre-scaling
     // MV. Note however that it performs the subsampling aware scaling so
     // that the result is always q4.
     // mv_precision precision is MV_PRECISION_Q4.
     const MV mv_q4 = clamp_mv_to_umv_border_sb(xd, &mv, bw, bh,
                                                pd->subsampling_x,
                                                pd->subsampling_y);
@@ skipping 76 matching lines @@
   const MODE_INFO *mi = xd->mi[0];
   const int is_compound = has_second_ref(&mi->mbmi);
   const InterpKernel *kernel = vp9_get_interp_kernel(mi->mbmi.interp_filter);
   int ref;
 
   for (ref = 0; ref < 1 + is_compound; ++ref) {
     const struct scale_factors *const sf = &xd->block_refs[ref]->sf;
     struct buf_2d *const pre_buf = &pd->pre[ref];
     struct buf_2d *const dst_buf = &pd->dst;
     uint8_t *const dst = dst_buf->buf + dst_buf->stride * y + x;
+    const MV mv = mi->mbmi.sb_type < BLOCK_8X8
+               ? average_split_mvs(pd, plane, mi, ref, block)
+               : mi->mbmi.mv[ref].as_mv;
 
-    // TODO(jkoleszar): All chroma MVs in SPLITMV mode are taken as the
-    // same MV (the average of the 4 luma MVs) but we could do something
-    // smarter for non-4:2:0. Just punt for now, pending the changes to get
-    // rid of SPLITMV mode entirely.
-    const MV mv = mi->mbmi.sb_type < BLOCK_8X8
-               ? (plane == 0 ? mi->bmi[block].as_mv[ref].as_mv
-                             : mi_mv_pred_q4(mi, ref))
-               : mi->mbmi.mv[ref].as_mv;
 
     // TODO(jkoleszar): This clamping is done in the incorrect place for the
     // scaling case. It needs to be done on the scaled MV, not the pre-scaling
     // MV. Note however that it performs the subsampling aware scaling so
     // that the result is always q4.
     // mv_precision precision is MV_PRECISION_Q4.
     const MV mv_q4 = clamp_mv_to_umv_border_sb(xd, &mv, bw, bh,
                                                pd->subsampling_x,
                                                pd->subsampling_y);
 
@@ skipping 156 matching lines @@
     const int strides[4] = {src->y_stride, src->uv_stride, src->uv_stride,
                             src->alpha_stride};
 
     for (i = 0; i < MAX_MB_PLANE; ++i) {
       struct macroblockd_plane *const pd = &xd->plane[i];
       setup_pred_plane(&pd->pre[idx], buffers[i], strides[i], mi_row, mi_col,
                        sf, pd->subsampling_x, pd->subsampling_y);
     }
   }
 }