add a new interp filter search strategy.

This commit addes a new strategy to reduce the search for optimal
interpolation filter type. The encoder counts and store how many each
filter type is selected and used for each of the reference frames.
A filter type that is rarely used for all three reference frames is
masked out to avoid computation.

The impact on compression is neglectible:
-0.02% on derf
+0.02% on stdhd

Encoding time is seen to reduce by 2~3%.

Change-Id: Ibafa92291b51185de40da513716222db4b230383

1 files changed, 51 insertions, 0 deletions

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index 0626f44a4..9f12d664c 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -131,8 +131,10 @@ static void setup_frame(VP9_COMP *cpi) {
     if (!is_spatial_svc(cpi))
       cpi->refresh_golden_frame = 1;
     cpi->refresh_alt_ref_frame = 1;
+    vp9_zero(cpi->interp_filter_selected);
   } else {
     cm->fc = cm->frame_contexts[cm->frame_context_idx];
+    vp9_zero(cpi->interp_filter_selected[0]);
   }
 }
 
@@ -1556,17 +1558,32 @@ void vp9_update_reference_frames(VP9_COMP *cpi) {
 
       ref_cnt_fb(cm->frame_bufs,
                  &cm->ref_frame_map[arf_idx], cm->new_fb_idx);
+      vpx_memcpy(cpi->interp_filter_selected[ALTREF_FRAME],
+                 cpi->interp_filter_selected[0],
+                 sizeof(cpi->interp_filter_selected[0]));
     }
 
     if (cpi->refresh_golden_frame) {
       ref_cnt_fb(cm->frame_bufs,
                  &cm->ref_frame_map[cpi->gld_fb_idx], cm->new_fb_idx);
+      if (!cpi->rc.is_src_frame_alt_ref)
+        vpx_memcpy(cpi->interp_filter_selected[GOLDEN_FRAME],
+                   cpi->interp_filter_selected[0],
+                   sizeof(cpi->interp_filter_selected[0]));
+      else
+        vpx_memcpy(cpi->interp_filter_selected[GOLDEN_FRAME],
+                   cpi->interp_filter_selected[ALTREF_FRAME],
+                   sizeof(cpi->interp_filter_selected[ALTREF_FRAME]));
     }
   }
 
   if (cpi->refresh_last_frame) {
     ref_cnt_fb(cm->frame_bufs,
                &cm->ref_frame_map[cpi->lst_fb_idx], cm->new_fb_idx);
+    if (!cpi->rc.is_src_frame_alt_ref)
+      vpx_memcpy(cpi->interp_filter_selected[LAST_FRAME],
+                 cpi->interp_filter_selected[0],
+                 sizeof(cpi->interp_filter_selected[0]));
   }
 #if CONFIG_VP9_TEMPORAL_DENOISING
   if (cpi->oxcf.noise_sensitivity > 0) {
@@ -2057,6 +2074,33 @@ static void set_mv_search_params(VP9_COMP *cpi) {
   }
 }
 
+
+int setup_interp_filter_search_mask(VP9_COMP *cpi) {
+  INTERP_FILTER ifilter;
+  int ref_total[MAX_REF_FRAMES] = {0};
+  MV_REFERENCE_FRAME ref;
+  int mask = 0;
+  if (cpi->common.last_frame_type == KEY_FRAME ||
+      cpi->refresh_alt_ref_frame)
+    return mask;
+  for (ref = LAST_FRAME; ref <= ALTREF_FRAME; ++ref)
+    for (ifilter = EIGHTTAP; ifilter <= EIGHTTAP_SHARP; ++ifilter)
+      ref_total[ref] += cpi->interp_filter_selected[ref][ifilter];
+
+  for (ifilter = EIGHTTAP; ifilter <= EIGHTTAP_SHARP; ++ifilter) {
+    if ((ref_total[LAST_FRAME] &&
+        cpi->interp_filter_selected[LAST_FRAME][ifilter] == 0) &&
+        (ref_total[GOLDEN_FRAME] == 0 ||
+         cpi->interp_filter_selected[GOLDEN_FRAME][ifilter] * 50
+           < ref_total[GOLDEN_FRAME]) &&
+        (ref_total[ALTREF_FRAME] == 0 ||
+         cpi->interp_filter_selected[ALTREF_FRAME][ifilter] * 50
+           < ref_total[ALTREF_FRAME]))
+      mask |= 1 << ifilter;
+  }
+  return mask;
+}
+
 static void encode_frame_to_data_rate(VP9_COMP *cpi,
                                       size_t *size,
                                       uint8_t *dest,
@@ -2095,6 +2139,12 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
 
   set_mv_search_params(cpi);
 
+  if (cpi->oxcf.pass == 2 &&
+      cpi->sf.adaptive_interp_filter_search)
+    cpi->sf.interp_filter_search_mask =
+        setup_interp_filter_search_mask(cpi);
+
+
   // Set various flags etc to special state if it is a key frame.
   if (frame_is_intra_only(cm)) {
     // Reset the loop filter deltas and segmentation map.
@@ -2813,6 +2863,7 @@ int vp9_get_compressed_data(VP9_COMP *cpi, unsigned int *frame_flags,
         }
       }
 
+
       if (cpi->b_calculate_ssimg) {
         double y, u, v, frame_all;
         frame_all = vp9_calc_ssimg(cpi->Source, cm->frame_to_show, &y, &u, &v);