Use variance metric for integral projection vector match

This commit replaces the SAD with variance as metric for the
integral projection vector match. It improves the search accuracy
in the presence of slight light change. The average speed -6
compression performance for rtc set is improved by 1.7%. No speed
changes are observed for the test clips.

Change-Id: I71c1d27e42de2aa429fb3564e6549bba1c7d6d4d

1 files changed, 9 insertions, 9 deletions

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index a5e9ed616..63ca2d34d 100644
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -519,14 +519,14 @@ void vp9_set_vbp_thresholds(VP9_COMP *cpi, int q) {
 #endif
 
 #if GLOBAL_MOTION
-static int vector_match(int16_t *ref, int16_t *src, int length) {
+static int vector_match(int16_t *ref, int16_t *src, int bwl) {
   int best_sad = INT_MAX;
   int this_sad;
   int d;
   int center, offset = 0;
-  int bw = length;  // redundant variable, to be changed in the experiments.
+  int bw = 4 << bwl;  // redundant variable, to be changed in the experiments.
   for (d = 0; d <= bw; d += 16) {
-    this_sad = vp9_vector_sad(&ref[d], src, length);
+    this_sad = vp9_vector_var(&ref[d], src, bwl);
     if (this_sad < best_sad) {
       best_sad = this_sad;
       offset = d;
@@ -539,7 +539,7 @@ static int vector_match(int16_t *ref, int16_t *src, int length) {
     // check limit
     if (this_pos < 0 || this_pos > bw)
       continue;
-    this_sad = vp9_vector_sad(&ref[this_pos], src, length);
+    this_sad = vp9_vector_var(&ref[this_pos], src, bwl);
     if (this_sad < best_sad) {
       best_sad = this_sad;
       center = this_pos;
@@ -552,7 +552,7 @@ static int vector_match(int16_t *ref, int16_t *src, int length) {
     // check limit
     if (this_pos < 0 || this_pos > bw)
       continue;
-    this_sad = vp9_vector_sad(&ref[this_pos], src, length);
+    this_sad = vp9_vector_var(&ref[this_pos], src, bwl);
     if (this_sad < best_sad) {
       best_sad = this_sad;
       center = this_pos;
@@ -565,7 +565,7 @@ static int vector_match(int16_t *ref, int16_t *src, int length) {
     // check limit
     if (this_pos < 0 || this_pos > bw)
       continue;
-    this_sad = vp9_vector_sad(&ref[this_pos], src, length);
+    this_sad = vp9_vector_var(&ref[this_pos], src, bwl);
     if (this_sad < best_sad) {
       best_sad = this_sad;
       center = this_pos;
@@ -578,7 +578,7 @@ static int vector_match(int16_t *ref, int16_t *src, int length) {
     // check limit
     if (this_pos < 0 || this_pos > bw)
       continue;
-    this_sad = vp9_vector_sad(&ref[this_pos], src, length);
+    this_sad = vp9_vector_var(&ref[this_pos], src, bwl);
     if (this_sad < best_sad) {
       best_sad = this_sad;
       center = this_pos;
@@ -638,8 +638,8 @@ static void motion_estimation(VP9_COMP *cpi, MACROBLOCK *x,
   }
 
   // Find the best match per 1-D search
-  tmp_mv->col = vector_match(hbuf, src_hbuf, bw);
-  tmp_mv->row = vector_match(vbuf, src_vbuf, bh);
+  tmp_mv->col = vector_match(hbuf, src_hbuf, b_width_log2_lookup[bsize]);
+  tmp_mv->row = vector_match(vbuf, src_vbuf, b_height_log2_lookup[bsize]);
 
   best_sad = INT_MAX;
   this_mv = *tmp_mv;