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Limit cyclic refresh on steady background blocks.

Use the existing QP condition on limiting cyclic refresh, and add
addiitonal condition that block has been encoded with zero/small motion
x frames in row (where x is at least several times the refresh period).
Additional condition only affect non-screen content mode.

This helps to improve visual stability for noisy input, where on steady
background areas the application of delta_qp may lead to encoding the noise.

Also added a change to use the true skip (after encoding) to update the
last QP.

Change-Id: I234a1128d017d284cf767fdb58ef6c59d809f679

--- a/vp9/encoder/vp9_aq_cyclicrefresh.c

+++ b/vp9/encoder/vp9_aq_cyclicrefresh.c

@@ -23,6 +23,7 @@

 CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) {

   size_t last_coded_q_map_size;

+  size_t consec_zero_mv_size;

   CYCLIC_REFRESH *const cr = vpx_calloc(1, sizeof(*cr));

   if (cr == NULL)

     return NULL;

@@ -41,6 +42,13 @@

   assert(MAXQ <= 255);

   memset(cr->last_coded_q_map, MAXQ, last_coded_q_map_size);

+  consec_zero_mv_size = mi_rows * mi_cols * sizeof(*cr->consec_zero_mv);

+  cr->consec_zero_mv = vpx_malloc(consec_zero_mv_size);

+  if (cr->consec_zero_mv == NULL) {

+    vpx_free(cr);

+    return NULL;

+  }

+  memset(cr->consec_zero_mv, 0, consec_zero_mv_size);

   return cr;

 }

@@ -47,6 +55,7 @@

 void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) {

   vpx_free(cr->map);

   vpx_free(cr->last_coded_q_map);

+  vpx_free(cr->consec_zero_mv);

   vpx_free(cr);

 }

@@ -228,22 +237,48 @@

       int map_offset = block_index + y * cm->mi_cols + x;

       cr->map[map_offset] = new_map_value;

       cpi->segmentation_map[map_offset] = mbmi->segment_id;

+    }

+}

+

+void vp9_cyclic_refresh_update_sb_postencode(VP9_COMP *const cpi,

+                                             const MB_MODE_INFO *const mbmi,

+                                             int mi_row, int mi_col,

+                                             BLOCK_SIZE bsize) {

+  const VP9_COMMON *const cm = &cpi->common;

+  CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

+  MV mv = mbmi->mv[0].as_mv;

+  const int bw = num_8x8_blocks_wide_lookup[bsize];

+  const int bh = num_8x8_blocks_high_lookup[bsize];

+  const int xmis = VPXMIN(cm->mi_cols - mi_col, bw);

+  const int ymis = VPXMIN(cm->mi_rows - mi_row, bh);

+  const int block_index = mi_row * cm->mi_cols + mi_col;

+  int x, y;

+  for (y = 0; y < ymis; y++)

+    for (x = 0; x < xmis; x++) {

+      int map_offset = block_index + y * cm->mi_cols + x;

       // Inter skip blocks were clearly not coded at the current qindex, so

       // don't update the map for them. For cases where motion is non-zero or

       // the reference frame isn't the previous frame, the previous value in

       // the map for this spatial location is not entirely correct.

-      if ((!is_inter_block(mbmi) || !skip) &&

+      if ((!is_inter_block(mbmi) || !mbmi->skip) &&

           mbmi->segment_id <= CR_SEGMENT_ID_BOOST2) {

         cr->last_coded_q_map[map_offset] = clamp(

             cm->base_qindex + cr->qindex_delta[mbmi->segment_id], 0, MAXQ);

-      } else if (is_inter_block(mbmi) && skip &&

+      } else if (is_inter_block(mbmi) && mbmi->skip &&

                  mbmi->segment_id <= CR_SEGMENT_ID_BOOST2) {

         cr->last_coded_q_map[map_offset] = VPXMIN(

             clamp(cm->base_qindex + cr->qindex_delta[mbmi->segment_id],

                   0, MAXQ),

             cr->last_coded_q_map[map_offset]);

+      // Update the consecutive zero/low_mv count.

+      if (is_inter_block(mbmi) && (abs(mv.row) < 8 && abs(mv.col) < 8)) {

+        if (cr->consec_zero_mv[map_offset] < 255)

+          cr->consec_zero_mv[map_offset]++;

+      } else {

+        cr->consec_zero_mv[map_offset] = 0;

       }

     }

+  }

 }

 // Update the actual number of blocks that were applied the segment delta q.

@@ -380,9 +415,10 @@

     int mi_row = sb_row_index * MI_BLOCK_SIZE;

     int mi_col = sb_col_index * MI_BLOCK_SIZE;

     int qindex_thresh =

-        cpi->oxcf.content == VP9E_CONTENT_SCREEN

-            ? vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)

-            : 0;

+        vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex);

+    int consec_zero_mv_thresh =

+        cpi->oxcf.content == VP9E_CONTENT_SCREEN ? 0

+        : 10 * (100 / cr->percent_refresh);

     assert(mi_row >= 0 && mi_row < cm->mi_rows);

     assert(mi_col >= 0 && mi_col < cm->mi_cols);

     bl_index = mi_row * cm->mi_cols + mi_col;

@@ -398,7 +434,8 @@

         // for possible boost/refresh (segment 1). The segment id may get

         // reset to 0 later if block gets coded anything other than ZEROMV.

         if (cr->map[bl_index2] == 0) {

-          if (cr->last_coded_q_map[bl_index2] > qindex_thresh)

+          if (cr->last_coded_q_map[bl_index2] > qindex_thresh ||

+              cr->consec_zero_mv[bl_index2] < consec_zero_mv_thresh)

             sum_map++;

         } else if (cr->map[bl_index2] < 0) {

           cr->map[bl_index2]++;

@@ -475,6 +512,8 @@

     if (cm->frame_type == KEY_FRAME) {

       memset(cr->last_coded_q_map, MAXQ,

              cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));

+      memset(cr->consec_zero_mv, 0,

+             cm->mi_rows * cm->mi_cols * sizeof(*cr->consec_zero_mv));

       cr->sb_index = 0;

     }

     return;

@@ -544,6 +583,8 @@

   const VP9_COMMON *const cm = &cpi->common;

   CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;

   memset(cr->map, 0, cm->mi_rows * cm->mi_cols);

+  memset(cr->last_coded_q_map, MAXQ, cm->mi_rows * cm->mi_cols);

+  memset(cr->consec_zero_mv, 0, cm->mi_rows * cm->mi_cols);

   cr->sb_index = 0;

   cpi->refresh_golden_frame = 1;

 }

--- a/vp9/encoder/vp9_aq_cyclicrefresh.h

+++ b/vp9/encoder/vp9_aq_cyclicrefresh.h

@@ -51,6 +51,8 @@

   signed char *map;

   // Map of the last q a block was coded at.

   uint8_t *last_coded_q_map;

+  // Count on how many consecutive times a block uses ZER0MV for encoding.

+  uint8_t *consec_zero_mv;

   // Thresholds applied to the projected rate/distortion of the coding block,

   // when deciding whether block should be refreshed.

   int64_t thresh_rate_sb;

@@ -91,6 +93,11 @@

                                        MB_MODE_INFO *const mbmi,

                                        int mi_row, int mi_col, BLOCK_SIZE bsize,

                                        int64_t rate, int64_t dist, int skip);

+

+void vp9_cyclic_refresh_update_sb_postencode(struct VP9_COMP *const cpi,

+                                             const MB_MODE_INFO *const mbmi,

+                                             int mi_row, int mi_col,

+                                             BLOCK_SIZE bsize);

 // Update the segmentation map, and related quantities: cyclic refresh map,

 // refresh sb_index, and target number of blocks to be refreshed.

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

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

@@ -4213,5 +4213,7 @@

     }

     ++td->counts->tx.tx_totals[mbmi->tx_size];

     ++td->counts->tx.tx_totals[get_uv_tx_size(mbmi, &xd->plane[1])];

+    if (cm->seg.enabled && cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ)

+      vp9_cyclic_refresh_update_sb_postencode(cpi, mbmi, mi_row, mi_col, bsize);

   }

 }

-- 

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