diff --git a/av1/encoder/allintra_vis.c b/av1/encoder/allintra_vis.c
index 0e3accf..c765e87 100644
--- a/av1/encoder/allintra_vis.c
+++ b/av1/encoder/allintra_vis.c
@@ -475,9 +475,14 @@
   CHECK_MEM_ERROR(cm, mb_delta_q[1],
                   aom_calloc(num_rows * num_cols, sizeof(*mb_delta_q[1])));
 
+  // Approximates the model change between current version (Spet 2021) and the
+  // baseline (July 2021).
+  const double model_change[] = { 3.0, 3.0 };
+  // The following parameters are fitted from user labeled data.
   const double a[] = { -23.06 * 4.0, -17.20 * 4.0 };
   const double b[] = { 0.004065, 0.003093 };
-  const double c[] = { 30.516 * 4.0, 42.100 * 4.0 };
+  const double c[] = { (30.516 + model_change[0]) * 4.0,
+                       (42.100 + model_change[1]) * 4.0 };
   int delta_q_avg[2] = { 0, 0 };
   // Loop through each SB block.
   for (int row = 0; row < num_rows; ++row) {