Merge "Add "unknown" status for noise estimation."

vp9/encoder/vp9_encodeframe.c

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index 89f2bd9..24eeb02 100644
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -923,7 +923,8 @@
       get_variance(&vt.split[i].part_variances.none);
       if (vt.split[i].part_variances.none.variance > thresholds[1] ||
           (!is_key_frame &&
-          vt.split[i].part_variances.none.variance > (3 * avg_16x16[i]) >> 2)) {
+          vt.split[i].part_variances.none.variance > (thresholds[1] >> 1) &&
+          vt.split[i].part_variances.none.variance > (avg_16x16[i] >> 1))) {
         force_split[i + 1] = 1;
         force_split[0] = 1;
       }