Remove CONSTRAIN_NEIGHBORING_MIN_MAX.

Remove one of the auto partition size cases.
This case can behaves badly in some types of animated content
and was only used for the rd encode path. A subsequent patch
will add additional checks to help further improve visual quality.

Change-Id: I0ebd8da3d45ab8501afa45d7959ced8c2d60ee4e

3 files changed, 3 insertions, 31 deletions

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index fa7a694c5..568314174 100644
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -2157,7 +2157,6 @@ static void rd_auto_partition_range(VP9_COMP *cpi, const TileInfo *const tile,
   int bh, bw;
   BLOCK_SIZE min_size = BLOCK_4X4;
   BLOCK_SIZE max_size = BLOCK_64X64;
-  int i = 0;
   int bs_hist[BLOCK_SIZES] = {0};
 
   // Trap case where we do not have a prediction.
@@ -2187,36 +2186,10 @@ static void rd_auto_partition_range(VP9_COMP *cpi, const TileInfo *const tile,
                                   bs_hist);
     }
 
-    // adjust observed min and max
+    // Adjust observed min and max for "relaxed" auto partition case.
     if (cpi->sf.auto_min_max_partition_size == RELAXED_NEIGHBORING_MIN_MAX) {
       min_size = min_partition_size[min_size];
       max_size = max_partition_size[max_size];
-    } else if (cpi->sf.auto_min_max_partition_size ==
-               CONSTRAIN_NEIGHBORING_MIN_MAX) {
-      // adjust the search range based on the histogram of the observed
-      // partition sizes from left, above the previous co-located blocks
-      int sum = 0;
-      int first_moment = 0;
-      int second_moment = 0;
-      int var_unnormalized = 0;
-
-      for (i = 0; i < BLOCK_SIZES; i++) {
-        sum += bs_hist[i];
-        first_moment += bs_hist[i] * i;
-        second_moment += bs_hist[i] * i * i;
-      }
-
-      // if variance is small enough,
-      // adjust the range around its mean size, which gives a tighter range
-      var_unnormalized = second_moment - first_moment * first_moment / sum;
-      if (var_unnormalized <= 4 * sum) {
-        int mean = first_moment / sum;
-        min_size = min_partition_size[mean];
-        max_size = max_partition_size[mean];
-      } else {
-        min_size = min_partition_size[min_size];
-        max_size = max_partition_size[max_size];
-      }
     }
   }
 
diff --git a/vp9/encoder/vp9_speed_features.c b/vp9/encoder/vp9_speed_features.c
index 4c5ba5df3..372f1673d 100644
--- a/vp9/encoder/vp9_speed_features.c
+++ b/vp9/encoder/vp9_speed_features.c
@@ -115,7 +115,7 @@ static void set_good_speed_feature(VP9_COMP *cpi, VP9_COMMON *cm,
                                  FLAG_SKIP_INTRA_LOWVAR;
     sf->disable_filter_search_var_thresh = 100;
     sf->comp_inter_joint_search_thresh = BLOCK_SIZES;
-    sf->auto_min_max_partition_size = CONSTRAIN_NEIGHBORING_MIN_MAX;
+    sf->auto_min_max_partition_size = RELAXED_NEIGHBORING_MIN_MAX;
 
     sf->allow_partition_search_skip = 1;
   }
diff --git a/vp9/encoder/vp9_speed_features.h b/vp9/encoder/vp9_speed_features.h
index 8722d9cec..ec2560e90 100644
--- a/vp9/encoder/vp9_speed_features.h
+++ b/vp9/encoder/vp9_speed_features.h
@@ -101,8 +101,7 @@ typedef enum {
 typedef enum {
   NOT_IN_USE = 0,
   RELAXED_NEIGHBORING_MIN_MAX = 1,
-  CONSTRAIN_NEIGHBORING_MIN_MAX = 2,
-  STRICT_NEIGHBORING_MIN_MAX = 3
+  STRICT_NEIGHBORING_MIN_MAX = 2
 } AUTO_MIN_MAX_MODE;
 
 typedef enum {