Change erroradvantage measure for global motion

lowres: -0.594% (BDRATE)

tempete: -5.609%
waterfall: -7.227%

Change-Id: Ia68ed6ab3dd6b5b17c3e33658c4b75be28796e8e

av1/common/warped_motion.c

diff --git a/av1/common/warped_motion.c b/av1/common/warped_motion.c
index f726fc6..eef5849 100644
--- a/av1/common/warped_motion.c
+++ b/av1/common/warped_motion.c
@@ -512,8 +512,8 @@
                warp_interpolate(ref, out[0], out[1], width, height, stride);
       no_gm_err = dst[(j - p_col) + (i - p_row) * p_stride] -
                   ref[(j - p_col) + (i - p_row) * stride];
-      gm_sumerr += gm_err * gm_err;
-      no_gm_sumerr += no_gm_err * no_gm_err;
+      gm_sumerr += abs(gm_err);
+      no_gm_sumerr += abs(no_gm_err);
     }
   }
   return (double)gm_sumerr / no_gm_sumerr;

av1/encoder/encodeframe.c

diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index b624cbb..657c86e 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -4613,7 +4613,7 @@
 
 #if CONFIG_GLOBAL_MOTION
 #define MIN_TRANS_THRESH (1 * GM_TRANS_DECODE_FACTOR)
-#define GLOBAL_MOTION_ADVANTAGE_THRESH 0.60
+#define GLOBAL_MOTION_ADVANTAGE_THRESH 0.75
 #define GLOBAL_MOTION_MODEL ROTZOOM
 
 // Adds some offset to a global motion parameter and handles