From 28881dcfda9082507ba806e35474e699877d4d0b Mon Sep 17 00:00:00 2001
From: Marco Paniconi <marpan@google.com>
Date: Fri, 15 Mar 2019 09:13:45 -0700
Subject: [PATCH] vp9-rtc: Adjustments for base layer in screen.

On scene/content changes for base layer of screen:
reduce 32x32 split threshold, bias rdcost for flat
blocks if sse_y is non-zero, and avoid early exit on
intra-check.

Reduce artifacts in scroll content.

Change-Id: I144357a61462351173af900e0b8a47dac4aad6ca
---
 vp9/encoder/vp9_encodeframe.c |  5 +++++
 vp9/encoder/vp9_pickmode.c    | 22 +++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index f624de1..ccb3584 100644
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -1352,6 +1352,11 @@ static int choose_partitioning(VP9_COMP *cpi, const TileInfo *const tile,
   } else {
     set_vbp_thresholds(cpi, thresholds, cm->base_qindex, content_state);
   }
+  // Decrease 32x32 split threshold for screen on base layer, for scene
+  // change/high motion frames.
+  if (cpi->oxcf.content == VP9E_CONTENT_SCREEN &&
+      cpi->svc.spatial_layer_id == 0 && force_64_split)
+    thresholds[1] = 3 * thresholds[1] >> 2;
 
   // For non keyframes, disable 4x4 average for low resolution when speed = 8
   threshold_4x4avg = (cpi->oxcf.speed < 8) ? thresholds[1] << 1 : INT64_MAX;
diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index b69b269..86831b9 100644
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -2337,7 +2337,8 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
 
     // Skipping checking: test to see if this block can be reconstructed by
     // prediction only.
-    if (cpi->allow_encode_breakout && !xd->lossless && !scene_change_detected) {
+    if (cpi->allow_encode_breakout && !xd->lossless && !scene_change_detected &&
+        !svc->high_num_blocks_with_motion) {
       encode_breakout_test(cpi, x, bsize, mi_row, mi_col, ref_frame, this_mode,
                            var_y, sse_y, yv12_mb, &this_rdc.rate,
                            &this_rdc.dist, flag_preduv_computed);
@@ -2348,6 +2349,15 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
       }
     }
 
+    // On spatially flat blocks for screne content: bias against zero-last
+    // if the sse_y is non-zero. Only on scene change or high motion frames.
+    if (cpi->oxcf.content == VP9E_CONTENT_SCREEN &&
+        (scene_change_detected || svc->high_num_blocks_with_motion) &&
+        ref_frame == LAST_FRAME && frame_mv[this_mode][ref_frame].as_int == 0 &&
+        svc->spatial_layer_id == 0 && x->source_variance == 0 && sse_y > 0) {
+      this_rdc.rdcost = this_rdc.rdcost << 2;
+    }
+
 #if CONFIG_VP9_TEMPORAL_DENOISING
     if (cpi->oxcf.noise_sensitivity > 0 && denoise_svc_pickmode &&
         cpi->denoiser.denoising_level > kDenLowLow) {
@@ -2489,8 +2499,14 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
                                       &rd_thresh_freq_fact[mode_index])) ||
           (!cpi->sf.adaptive_rd_thresh_row_mt &&
            rd_less_than_thresh(best_rdc.rdcost, mode_rd_thresh,
-                               &rd_thresh_freq_fact[mode_index])))
-        continue;
+                               &rd_thresh_freq_fact[mode_index]))) {
+        // Avoid this early exit for screen on base layer, for scene
+        // changes or high motion frames.
+        if (cpi->oxcf.content != VP9E_CONTENT_SCREEN ||
+            svc->spatial_layer_id > 0 ||
+            (!scene_change_detected && !svc->high_num_blocks_with_motion))
+          continue;
+      }
 
       mi->mode = this_mode;
       mi->ref_frame[0] = INTRA_FRAME;
-- 
2.7.4