vp9: Reduce quality artifact for real-time scene-content.

Add scene detection flag to choose_partitioning to force split
of 64x64 block partition. This reduces artifacts on slide changes.

Bug:b/110978869

Change-Id: I9cc79a7c03f3aa2edeb28656b09a2177b72d59a8

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index 34eaeb78366d4626067c69dcb7b1b0ba987134d7..d48474ece2c4cba16289bbff4621898ec800ad65 100644 (file)
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -592,6 +592,11 @@ void vp9_set_variance_partition_thresholds(VP9_COMP *cpi, int q,
         cpi->vbp_threshold_copy = (cpi->y_dequant[q][1] << 3) > 8000
                                       ? (cpi->y_dequant[q][1] << 3)
                                       : 8000;
+      if (cpi->rc.high_source_sad ||
+          (cpi->use_svc && cpi->svc.high_source_sad_superframe)) {
+        cpi->vbp_threshold_sad = 0;
+        cpi->vbp_threshold_copy = 0;
+      }
     }
     cpi->vbp_threshold_minmax = 15 + (q >> 3);
   }
@@ -1213,6 +1218,9 @@ static int choose_partitioning(VP9_COMP *cpi, const TileInfo *const tile,
   int pixels_wide = 64, pixels_high = 64;
   int64_t thresholds[4] = { cpi->vbp_thresholds[0], cpi->vbp_thresholds[1],
                             cpi->vbp_thresholds[2], cpi->vbp_thresholds[3] };
+  int scene_change_detected =
+      cpi->rc.high_source_sad ||
+      (cpi->use_svc && cpi->svc.high_source_sad_superframe);
 
   // For the variance computation under SVC mode, we treat the frame as key if
   // the reference (base layer frame) is key frame (i.e., is_key_frame == 1).
@@ -1274,6 +1282,7 @@ static int choose_partitioning(VP9_COMP *cpi, const TileInfo *const tile,
     }
     // If source_sad is low copy the partition without computing the y_sad.
     if (x->skip_low_source_sad && cpi->sf.copy_partition_flag &&
+        !scene_change_detected &&
         copy_partitioning(cpi, x, xd, mi_row, mi_col, segment_id, sb_offset)) {
       x->sb_use_mv_part = 1;
       if (cpi->sf.svc_use_lowres_part &&
@@ -1302,7 +1311,7 @@ static int choose_partitioning(VP9_COMP *cpi, const TileInfo *const tile,
 
   // Index for force_split: 0 for 64x64, 1-4 for 32x32 blocks,
   // 5-20 for the 16x16 blocks.
-  force_split[0] = 0;
+  force_split[0] = scene_change_detected;
 
   if (!is_key_frame) {
     // In the case of spatial/temporal scalable coding, the assumption here is