Improve high bit-rate encoding of deltaq-mode=4

Change-Id: I9e381254a1819970750a22b17d0d7e1cb193e9fa
diff --git a/av1/encoder/allintra_vis.c b/av1/encoder/allintra_vis.c
index 61fea0e..84fa763 100644
--- a/av1/encoder/allintra_vis.c
+++ b/av1/encoder/allintra_vis.c
@@ -534,7 +534,7 @@
   const int cq_level = cpi->oxcf.rc_cfg.cq_level;
   if (cq_level < delta_q_avg[0]) {
     model_idx = 0;
-    scaling_factor = 1.0;
+    scaling_factor = (double)cq_level / delta_q_avg[0];
   } else if (cq_level < delta_q_avg[1]) {
     model_idx = 2;
     scaling_factor =