vp9: Reduce qp threshold for limiting cyclic refresh on steady blocks.

Makes the delta-qp stop little earlier on areas that have been refreshed enough.
This helps to reduce some pulsing artifact on noisy flat areas observed in some
noisy vc-clips.

Threshold changes only take effect for sources where noise level is estimated to
be >= medium level.

Only affects 1 pass CBR, non-screen content case.

Change-Id: Iacf557f6aa8abbcd6782c02ff2e6c14891960850

vp9/encoder/vp9_aq_cyclicrefresh.c

diff --git a/vp9/encoder/vp9_aq_cyclicrefresh.c b/vp9/encoder/vp9_aq_cyclicrefresh.c
index 6b65103..3e1a0a5 100644
--- a/vp9/encoder/vp9_aq_cyclicrefresh.c
+++ b/vp9/encoder/vp9_aq_cyclicrefresh.c
@@ -393,13 +393,18 @@
   cr->target_num_seg_blocks = 0;
   if (cpi->oxcf.content != VP9E_CONTENT_SCREEN) {
     consec_zero_mv_thresh = 100;
-   if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium)
-     consec_zero_mv_thresh = 80;
   }
   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);
+  // More aggressive settings for noisy content.
+  if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium) {
+    consec_zero_mv_thresh = 80;
+    qindex_thresh =
+        VPXMAX(vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST1, cm->base_qindex),
+                              7 * cm->base_qindex >> 3);
+  }
   do {
     int sum_map = 0;
     // Get the mi_row/mi_col corresponding to superblock index i.
@@ -463,6 +468,8 @@
     cr->percent_refresh = 5;
   cr->max_qdelta_perc = 50;
   cr->time_for_refresh = 0;
+  cr->motion_thresh = 32;
+  cr->rate_boost_fac = 15;
   // Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4)
   // periods of the refresh cycle, after a key frame.
   // Account for larger interval on base layer for temporal layers.
@@ -472,9 +479,11 @@
     cr->rate_ratio_qdelta = 3.0;
   } else {
     cr->rate_ratio_qdelta = 2.0;
-  if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium)
-    // Reduce the delta-qp if the estimated source noise is above threshold.
-    cr->rate_ratio_qdelta = 1.5;
+    if (cpi->noise_estimate.enabled && cpi->noise_estimate.level >= kMedium) {
+      // Reduce the delta-qp if the estimated source noise is above threshold.
+      cr->rate_ratio_qdelta = 1.7;
+      cr->rate_boost_fac = 13;
+    }
   }
   // Adjust some parameters for low resolutions at low bitrates.
   if (cm->width <= 352 &&
@@ -482,9 +491,6 @@
       rc->avg_frame_bandwidth < 3400) {
     cr->motion_thresh = 4;
     cr->rate_boost_fac = 10;
-  } else {
-    cr->motion_thresh = 32;
-    cr->rate_boost_fac = 15;
   }
   if (cpi->svc.spatial_layer_id > 0) {
     cr->motion_thresh = 4;