vp9_pick_inter_mode(): minor optimizations

1. remove duplicate initialization to mbmi->interp_filter.
2. move mv clamping into ref_frame loop instead of mode checking loop.
3. move the check if last frame is same as golden frame earlier to
avoid initialization of Golden reference related variables.

Change-Id: Idf2d05e19e94a24f69cc289687869fc71d2ff289

1 files changed, 16 insertions, 21 deletions

diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index 88003ec17..5bc9fcad7 100644
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -636,6 +636,7 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
   struct macroblockd_plane *const pd = &xd->plane[0];
   PREDICTION_MODE best_mode = ZEROMV;
   MV_REFERENCE_FRAME ref_frame, best_ref_frame = LAST_FRAME;
+  MV_REFERENCE_FRAME usable_ref_frame;
   TX_SIZE best_tx_size = TX_SIZES;
   INTERP_FILTER best_pred_filter = EIGHTTAP;
   int_mv frame_mv[MB_MODE_COUNT][MAX_REF_FRAMES];
@@ -718,14 +719,17 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
   mbmi->ref_frame[1] = NONE;
   mbmi->tx_size = MIN(max_txsize_lookup[bsize],
                       tx_mode_to_biggest_tx_size[cm->tx_mode]);
-  mbmi->interp_filter = cm->interp_filter == SWITCHABLE ?
-                        EIGHTTAP : cm->interp_filter;
 
 #if CONFIG_VP9_TEMPORAL_DENOISING
   vp9_denoiser_reset_frame_stats(ctx);
 #endif
-
-  for (ref_frame = LAST_FRAME; ref_frame <= GOLDEN_FRAME; ++ref_frame) {
+  if (cpi->rc.frames_since_golden == 0) {
+    ref_frame_skip_mask |= (1 << GOLDEN_FRAME);
+    usable_ref_frame = LAST_FRAME;
+  } else {
+    usable_ref_frame = GOLDEN_FRAME;
+  }
+  for (ref_frame = LAST_FRAME; ref_frame <= usable_ref_frame; ++ref_frame) {
     const YV12_BUFFER_CONFIG *yv12 = get_ref_frame_buffer(cpi, ref_frame);
 
     x->pred_mv_sad[ref_frame] = INT_MAX;
@@ -751,6 +755,8 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
       vp9_find_best_ref_mvs(xd, cm->allow_high_precision_mv, candidates,
                             &frame_mv[NEARESTMV][ref_frame],
                             &frame_mv[NEARMV][ref_frame]);
+      clamp_mv2(&frame_mv[NEARESTMV][ref_frame].as_mv, xd);
+      clamp_mv2(&frame_mv[NEARMV][ref_frame].as_mv, xd);
 
       if (!vp9_is_scaled(sf) && bsize >= BLOCK_8X8)
         vp9_mv_pred(cpi, x, yv12_mb[ref_frame][0].buf, yv12->y_stride,
@@ -760,28 +766,25 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
     }
   }
 
-  if (cpi->rc.frames_since_golden == 0)
-    ref_frame_skip_mask |= (1 << GOLDEN_FRAME);
-
   for (idx = 0; idx < RT_INTER_MODES; ++idx) {
     int rate_mv = 0;
     int mode_rd_thresh;
     int mode_index;
     int i;
     PREDICTION_MODE this_mode = ref_mode_set[idx].pred_mode;
+    if (!(cpi->sf.inter_mode_mask[bsize] & (1 << this_mode)))
+      continue;
 
     ref_frame = ref_mode_set[idx].ref_frame;
-    mode_index = mode_idx[ref_frame][INTER_OFFSET(this_mode)];
-
-    i = (ref_frame == LAST_FRAME) ? GOLDEN_FRAME : LAST_FRAME;
-
     if (!(cpi->ref_frame_flags & flag_list[ref_frame]))
       continue;
+    if (const_motion[ref_frame] && this_mode == NEARMV)
+      continue;
 
+    i = (ref_frame == LAST_FRAME) ? GOLDEN_FRAME : LAST_FRAME;
     if (cpi->ref_frame_flags & flag_list[i])
       if (x->pred_mv_sad[ref_frame] > (x->pred_mv_sad[i] << 1))
         ref_frame_skip_mask |= (1 << ref_frame);
-
     if (ref_frame_skip_mask & (1 << ref_frame))
       continue;
 
@@ -789,18 +792,10 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x,
     for (i = 0; i < MAX_MB_PLANE; i++)
       xd->plane[i].pre[0] = yv12_mb[ref_frame][i];
 
-    clamp_mv2(&frame_mv[NEARESTMV][ref_frame].as_mv, xd);
-    clamp_mv2(&frame_mv[NEARMV][ref_frame].as_mv, xd);
-
     mbmi->ref_frame[0] = ref_frame;
     set_ref_ptrs(cm, xd, ref_frame, NONE);
 
-    if (const_motion[ref_frame] && this_mode == NEARMV)
-      continue;
-
-    if (!(cpi->sf.inter_mode_mask[bsize] & (1 << this_mode)))
-      continue;
-
+    mode_index = mode_idx[ref_frame][INTER_OFFSET(this_mode)];
     mode_rd_thresh = best_mode_skip_txfm ?
             rd_threshes[mode_index] << 1 : rd_threshes[mode_index];
     if (rd_less_than_thresh(best_rdc.rdcost, mode_rd_thresh,