Adjustment on limiting cyclic refresh on steady blocks.

Adjust the qp threshold and consec_zeromv threshold for
limiting cyclic refresh. Also increase the refresh period
when the limit amount is significant, and some code-cleanup.

Small gain in PSNR/SSIM metrics: ~0.25/0.3 gain on RTC set, speed 7.

Change only affects non-screen content.

Change-Id: I1ced87a89a132684c071e722616e445b2d18236a

vp9/encoder/vp9_aq_cyclicrefresh.c

@@ -167,7 +167,8 @@ int vp9_cyclic_refresh_rc_bits_per_mb(const VP9_COMP *cpi, int i,
   int num8x8bl = cm->MBs << 2;
   // Weight for segment prior to encoding: take the average of the target
   // number for the frame to be encoded and the actual from the previous frame.
-  double weight_segment = (double)((cr->target_num_seg_blocks +
+  int target_refresh = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100;
+  double weight_segment = (double)((target_refresh +
       cr->actual_num_seg1_blocks + cr->actual_num_seg2_blocks) >> 1) /
       num8x8bl;
   // Compute delta-q corresponding to qindex i.
@@ -208,7 +209,7 @@ void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi,
   // segment_id.
   if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) {
     mbmi->segment_id = refresh_this_block;
-    // Reset segment_id if will be skipped.
+    // Reset segment_id if it will be skipped.
     if (skip)
       mbmi->segment_id = CR_SEGMENT_ID_BASE;
   }
@@ -396,6 +397,9 @@ static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
   int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame;
   int xmis, ymis, x, y;
   int consec_zero_mv_thresh = 0;
+  int qindex_thresh = 0;
+  int count_sel = 0;
+  int count_tot = 0;
   memset(seg_map, CR_SEGMENT_ID_BASE, cm->mi_rows * cm->mi_cols);
   sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
   sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
@@ -408,9 +412,12 @@ static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
   assert(cr->sb_index < sbs_in_frame);
   i = cr->sb_index;
   cr->target_num_seg_blocks = 0;
-  if (cpi->oxcf.content != VP9E_CONTENT_SCREEN &&
-      cr->percent_refresh > 0)
-    consec_zero_mv_thresh = 10 * (100 / cr->percent_refresh);
+  if (cpi->oxcf.content != VP9E_CONTENT_SCREEN)
+    consec_zero_mv_thresh = 100;
+  qindex_thresh =
+      cpi->oxcf.content == VP9E_CONTENT_SCREEN
+      ? vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)
+      : vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST1, cm->base_qindex);
   do {
     int sum_map = 0;
     // Get the mi_row/mi_col corresponding to superblock index i.
@@ -418,8 +425,6 @@ static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
     int sb_col_index = i - sb_row_index * sb_cols;
     int mi_row = sb_row_index * MI_BLOCK_SIZE;
     int mi_col = sb_col_index * MI_BLOCK_SIZE;
-    int qindex_thresh =
-        vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex);
     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;
@@ -435,9 +440,12 @@ static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
         // 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) {
+          count_tot++;
           if (cr->last_coded_q_map[bl_index2] > qindex_thresh ||
-              cr->consec_zero_mv[bl_index2] < consec_zero_mv_thresh)
+              cr->consec_zero_mv[bl_index2] < consec_zero_mv_thresh) {
             sum_map++;
+            count_sel++;
+          }
         } else if (cr->map[bl_index2] < 0) {
           cr->map[bl_index2]++;
         }
@@ -458,6 +466,9 @@ static void cyclic_refresh_update_map(VP9_COMP *const cpi) {
     }
   } while (cr->target_num_seg_blocks < block_count && i != cr->sb_index);
   cr->sb_index = i;
+  cr->reduce_refresh = 0;
+  if (count_sel < (3 * count_tot) >> 2)
+    cr->reduce_refresh = 1;
 }
 
 // Set cyclic refresh parameters.
@@ -466,6 +477,8 @@ void vp9_cyclic_refresh_update_parameters(VP9_COMP *const cpi) {
   const VP9_COMMON *const cm = &cpi->common;
   CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
   cr->percent_refresh = 10;
+  if (cr->reduce_refresh)
+    cr->percent_refresh = 5;
   cr->max_qdelta_perc = 50;
   cr->time_for_refresh = 0;
   // Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4)

vp9/encoder/vp9_aq_cyclicrefresh.h

@@ -66,6 +66,7 @@ struct CYCLIC_REFRESH {
   int rate_boost_fac;
   double low_content_avg;
   int qindex_delta[3];
+  int reduce_refresh;
 };
 
 struct VP9_COMP;