shithub: libvpx

Info  •  Files  •  Log  •  Branches

vp9: Fix to screen content artifact for real-time.

Reset segment to base (segment#0) on spatially flat
stationary blocks (source_variance = 0). Also increase
dc_skip threshold for these blocks.

Reduces artifacts on flat areas in screen content mode.

Change-Id: I7ee0c80d37536db7896fa74a83f75799f1dcf73d

--- a/vp9/encoder/vp9_block.h

+++ b/vp9/encoder/vp9_block.h

@@ -180,6 +180,8 @@

   int sb_pickmode_part;

+  int zero_temp_sad_source;

+

   // For each superblock: saves the content value (e.g., low/high sad/sumdiff)

   // based on source sad, prior to encoding the frame.

   uint8_t content_state_sb;

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

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

@@ -1183,6 +1183,7 @@

       cpi->content_state_sb_fd[sb_offset] = 0;

     }

   }

+  if (tmp_sad == 0) x->zero_temp_sad_source = 1;

   return tmp_sad;

 }

@@ -4950,6 +4951,7 @@

     x->skip_low_source_sad = 0;

     x->lowvar_highsumdiff = 0;

     x->content_state_sb = 0;

+    x->zero_temp_sad_source = 0;

     x->sb_use_mv_part = 0;

     x->sb_mvcol_part = 0;

     x->sb_mvrow_part = 0;

--- a/vp9/encoder/vp9_pickmode.c

+++ b/vp9/encoder/vp9_pickmode.c

@@ -350,7 +350,7 @@

   struct macroblockd_plane *const pd = &xd->plane[0];

   const uint32_t dc_quant = pd->dequant[0];

   const uint32_t ac_quant = pd->dequant[1];

-  const int64_t dc_thr = dc_quant * dc_quant >> 6;

+  int64_t dc_thr = dc_quant * dc_quant >> 6;

   int64_t ac_thr = ac_quant * ac_quant >> 6;

   unsigned int var;

   int sum;

@@ -414,6 +414,10 @@

   assert(tx_size >= TX_8X8);

   xd->mi[0]->tx_size = tx_size;

+  if (cpi->oxcf.content == VP9E_CONTENT_SCREEN && x->zero_temp_sad_source &&

+      x->source_variance == 0)

+    dc_thr = dc_thr << 1;

+

   // Evaluate if the partition block is a skippable block in Y plane.

   {

     unsigned int sse16x16[16] = { 0 };

@@ -1605,6 +1609,12 @@

 #endif  // CONFIG_VP9_HIGHBITDEPTH

       x->source_variance =

           vp9_get_sby_perpixel_variance(cpi, &x->plane[0].src, bsize);

+

+    if (cpi->oxcf.content == VP9E_CONTENT_SCREEN && mi->segment_id > 0 &&

+        x->zero_temp_sad_source && x->source_variance == 0) {

+      mi->segment_id = 0;

+      vp9_init_plane_quantizers(cpi, x);

+    }

   }

 #if CONFIG_VP9_TEMPORAL_DENOISING

-- 

⑨