shithub: libvpx

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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

--- a/vp9/encoder/vp9_encodeframe.c

+++ b/vp9/encoder/vp9_encodeframe.c

@@ -592,6 +592,11 @@

         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 @@

   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 @@

     }

     // 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 @@

   // 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