vp9: Adjust threshold for y sad used in copying partition.

Visual quality improvement is observed for noisy clips. Little effects
on speed tests on Nexus 6.

Change-Id: Ib38e04002220708c34102de7b5c36e9940775d89

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index 913ef90e27df41a680111f0f65cd1ae268f9d10c..079215c099823035c78addadcab404a031201efe 100644 (file)
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -531,9 +531,9 @@ void vp9_set_variance_partition_thresholds(VP9_COMP *cpi, int q) {
       else if (cm->width <= 640 && cm->height <= 360)
         cpi->vbp_threshold_copy = 8000;
       else
-        cpi->vbp_threshold_copy = (cpi->y_dequant[q][1] << 4) > 16000
-                                      ? (cpi->y_dequant[q][1] << 4)
-                                      : 16000;
+        cpi->vbp_threshold_copy = (cpi->y_dequant[q][1] << 3) > 8000
+                                      ? (cpi->y_dequant[q][1] << 3)
+                                      : 8000;
     }
     cpi->vbp_threshold_minmax = 15 + (q >> 3);
   }