diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index 588d058..ae9dbaa 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -149,7 +149,10 @@
 #endif  // CONFIG_AV1_HIGHBITDEPTH
 /*!\endcond */
 
-const uint8_t *av1_var_offs(int use_hbd, int bd) {
+// For the given bit depth, returns a constant array used to assist the
+// calculation of source block variance, which will then be used to decide
+// adaptive quantizers.
+static const uint8_t *get_var_offs(int use_hbd, int bd) {
 #if CONFIG_AV1_HIGHBITDEPTH
   if (use_hbd) {
     assert(bd == 8 || bd == 10 || bd == 12);
@@ -190,7 +193,7 @@
       get_plane_block_size(bsize, subsampling_x, subsampling_y);
   unsigned int sse;
   const unsigned int var = cpi->ppi->fn_ptr[plane_bsize].vf(
-      ref->buf, ref->stride, av1_var_offs(use_hbd, xd->bd), 0, &sse);
+      ref->buf, ref->stride, get_var_offs(use_hbd, xd->bd), 0, &sse);
   return ROUND_POWER_OF_TWO(var, num_pels_log2_lookup[plane_bsize]);
 }
 
diff --git a/av1/encoder/encodeframe.h b/av1/encoder/encodeframe.h
index 0f3511d..ce32fb4 100644
--- a/av1/encoder/encodeframe.h
+++ b/av1/encoder/encodeframe.h
@@ -31,11 +31,6 @@
 struct AV1_COMP;
 struct ThreadData;
 
-// For the given bit depth, returns a constant array used to assist the
-// calculation of source block variance, which will then be used to decide
-// adaptive quantizers.
-const uint8_t *av1_var_offs(int use_hbd, int bd);
-
 void av1_init_rtc_counters(struct macroblock *const x);
 
 void av1_accumulate_rtc_counters(struct AV1_COMP *cpi,
diff --git a/av1/encoder/var_based_part.c b/av1/encoder/var_based_part.c
index 4a1186f..05e0383 100644
--- a/av1/encoder/var_based_part.c
+++ b/av1/encoder/var_based_part.c
@@ -1113,6 +1113,8 @@
   int pixels_wide = 128, pixels_high = 128;
   int border_offset_4x4 = 0;
   int temporal_denoising = cpi->sf.rt_sf.use_rtc_tf;
+  // dst_buf pointer is not used for is_key_frame, so it should be NULL.
+  assert(IMPLIES(is_key_frame, dst_buf == NULL));
   if (is_small_sb) {
     pixels_wide = 64;
     pixels_high = 64;
@@ -1646,7 +1648,7 @@
       dst_stride = xd->plane[AOM_PLANE_Y].pre[0].stride;
     }
   } else {
-    dst_buf = av1_var_offs(is_cur_buf_hbd(xd), xd->bd);
+    dst_buf = NULL;
     dst_stride = 0;
   }