rtc-screen: Improve conditions for better motion search

For screen: increased motion search was set based
on high_num_blocks_motion. This CL changes that and
sets it based on source sad metrics, and updated/added
new metrics in the scene detection.

This makes the increased motion search
setting more aggressive but also more targeted.

Stats for speed 10 screen:
avg_psnr/ovr_psnr/ssim, IC speedup
-2.7/-3.7/-4.1, -1.2%

youtube clip has gains: -9/-12/-11, but 7% IC slowdown

Change-Id: I984d35b09b4a251aa19790eb1b3c621ee0ab9db5

av1/encoder/ratectrl.c

diff --git a/av1/encoder/ratectrl.c b/av1/encoder/ratectrl.c
index 33b6b6d..315bae6 100644
--- a/av1/encoder/ratectrl.c
+++ b/av1/encoder/ratectrl.c
@@ -2761,7 +2761,8 @@
     return;
   }
   rc->high_source_sad = 0;
-  rc->high_num_blocks_with_motion = 0;
+  rc->percent_blocks_with_motion = 0;
+  rc->max_block_source_sad = 0;
   rc->prev_avg_source_sad = rc->avg_source_sad;
   if (src_width == last_src_width && src_height == last_src_height) {
     const int num_mi_cols = cm->mi_params.mi_cols;
@@ -2815,6 +2816,8 @@
         avg_sad += tmp_sad;
         num_samples++;
         if (tmp_sad == 0) num_zero_temp_sad++;
+        if (tmp_sad > rc->max_block_source_sad)
+          rc->max_block_source_sad = tmp_sad;
 
         src_y += 64;
         last_src_y += 64;
@@ -2840,9 +2843,9 @@
       rc->high_source_sad = 0;
     rc->avg_source_sad = (3 * rc->avg_source_sad + avg_sad) >> 2;
     rc->frame_source_sad = avg_sad;
-
-    if (num_zero_temp_sad < (3 * num_samples >> 2))
-      rc->high_num_blocks_with_motion = 1;
+    if (num_samples > 0)
+      rc->percent_blocks_with_motion =
+          ((num_samples - num_zero_temp_sad) * 100) / num_samples;
   }
   cpi->svc.high_source_sad_superframe = rc->high_source_sad;
 }

av1/encoder/ratectrl.h

diff --git a/av1/encoder/ratectrl.h b/av1/encoder/ratectrl.h
index 6a678b7..df177b9 100644
--- a/av1/encoder/ratectrl.h
+++ b/av1/encoder/ratectrl.h
@@ -238,7 +238,10 @@
   int cnt_zeromv;
 
   // signals if number of blocks with motion is high
-  int high_num_blocks_with_motion;
+  int percent_blocks_with_motion;
+
+  // Maximum value of source sad across all blocks of frame.
+  uint64_t max_block_source_sad;
 
   // For dynamic resize, 1 pass cbr.
   RESIZE_STATE resize_state;

av1/encoder/speed_features.c

diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index ab3ef83..8c545ff 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -1449,7 +1449,9 @@
           sf->rt_sf.intra_y_mode_bsize_mask_nrd[i] = INTRA_DC_H_V;
       }
     }
-    if (cpi->rc.high_num_blocks_with_motion && speed >= 6) {
+    if (cpi->rc.max_block_source_sad > 20000 &&
+        cpi->rc.frame_source_sad > 100 &&
+        cpi->rc.percent_blocks_with_motion > 1 && speed >= 6) {
       sf->mv_sf.search_method = NSTEP;
       sf->rt_sf.fullpel_search_step_param = 2;
     }