diff --git a/src/rdo.c b/src/rdo.c
index 456763b3..0aaf2736 100644
--- a/src/rdo.c
+++ b/src/rdo.c
@@ -840,7 +840,8 @@ void  kvz_rdoq(encoder_state_t * const state, coeff_t *coef, coeff_t *dest_coeff
 * \returns int
 * Calculates cost of actual motion vectors using CABAC coding
 */
-uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t *mvd, cabac_data_t* cabac) {
+uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t *mvd, const cabac_data_t* real_cabac)
+{
   uint32_t bitcost = 0;
   const int32_t mvd_hor = mvd->x;
   const int32_t mvd_ver = mvd->y;
@@ -850,7 +851,8 @@ uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t
   const uint32_t mvd_ver_abs = abs(mvd_ver);
 
   cabac_data_t cabac_copy;
-  memcpy(&cabac_copy, cabac, sizeof(cabac_data_t));
+  memcpy(&cabac_copy, real_cabac, sizeof(cabac_data_t));
+  cabac_data_t *cabac = &cabac_copy;
   cabac->only_count = 1;
 
   cabac->cur_ctx = &(cabac->ctx.cu_mvd_model[0]);
@@ -875,9 +877,7 @@ uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t
     }
     CABAC_BIN_EP(cabac, (mvd_ver > 0) ? 0 : 1, "mvd_sign_flag_ver");
   }
-  bitcost = ((23 - cabac->bits_left) + (cabac->num_buffered_bytes << 3)) - ((23 - cabac_copy.bits_left) + (cabac_copy.num_buffered_bytes << 3));
-
-  memcpy(cabac, &cabac_copy, sizeof(cabac_data_t));
+  bitcost = ((23 - cabac->bits_left) + (cabac->num_buffered_bytes << 3)) - ((23 - real_cabac->bits_left) + (real_cabac->num_buffered_bytes << 3));
 
   return bitcost;
 }
diff --git a/src/rdo.h b/src/rdo.h
index f6bf1325..636ee80b 100644
--- a/src/rdo.h
+++ b/src/rdo.h
@@ -52,7 +52,7 @@ uint32_t kvz_get_coded_level(encoder_state_t * state, double* coded_cost, double
 
 kvz_mvd_cost_func kvz_calc_mvd_cost_cabac;
 
-uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t *mvd, cabac_data_t* cabac);
+uint32_t kvz_get_mvd_coding_cost_cabac(encoder_state_t * const state, vector2d_t *mvd, const cabac_data_t* cabac);
 
 uint8_t kvz_skip_unnecessary_rdoq(encoder_state_t * const state, coeff_t *coef, coeff_t *dest_coeff, int32_t width,
               int32_t height, int8_t type, int8_t scan_mode, int8_t block_type);
diff --git a/src/search_inter.c b/src/search_inter.c
index df2cba1b..51c482d7 100644
--- a/src/search_inter.c
+++ b/src/search_inter.c
@@ -175,7 +175,7 @@ static unsigned select_starting_point(int16_t num_cand, inter_merge_cand_t *merg
 }
 
 
-static uint32_t get_mvd_coding_cost(encoder_state_t * const state, vector2d_t *mvd, cabac_data_t* cabac)
+static uint32_t get_mvd_coding_cost(encoder_state_t * const state, vector2d_t *mvd, const cabac_data_t* cabac)
 {
   uint32_t bitcost = 0;
   const int32_t mvd_hor = mvd->x;
@@ -1223,7 +1223,7 @@ static void search_pu_inter_ref(encoder_state_t * const state,
                                 inter_merge_cand_t merge_cand[MRG_MAX_NUM_CANDS],
                                 int16_t num_cand,
                                 unsigned ref_idx,
-                                uint32_t(*get_mvd_cost)(encoder_state_t * const, vector2d_t *, cabac_data_t*),
+                                uint32_t(*get_mvd_cost)(encoder_state_t * const, vector2d_t *, const cabac_data_t*),
                                 double *inter_cost,
                                 uint32_t *inter_bitcost)
 {
@@ -1363,11 +1363,11 @@ static void search_pu_inter_ref(encoder_state_t * const state,
 
     mvd_temp1.x = mv.x - mv_cand[0][0];
     mvd_temp1.y = mv.y - mv_cand[0][1];
-    cand1_cost = get_mvd_cost(state, &mvd_temp1, (cabac_data_t*)&state->cabac);
+    cand1_cost = get_mvd_cost(state, &mvd_temp1, &state->cabac);
 
     mvd_temp2.x = mv.x - mv_cand[1][0];
     mvd_temp2.y = mv.y - mv_cand[1][1];
-    cand2_cost = get_mvd_cost(state, &mvd_temp2, (cabac_data_t*)&state->cabac);
+    cand2_cost = get_mvd_cost(state, &mvd_temp2, &state->cabac);
 
     // Select candidate 1 if it has lower cost
     if (cand2_cost < cand1_cost) {
@@ -1448,7 +1448,7 @@ static void search_pu_inter(encoder_state_t * const state,
                                               merge_cand,
                                               lcu);
 
-  uint32_t(*get_mvd_cost)(encoder_state_t * const state, vector2d_t *, cabac_data_t*) = get_mvd_coding_cost;
+  uint32_t(*get_mvd_cost)(encoder_state_t * const state, vector2d_t *, const cabac_data_t*) = get_mvd_coding_cost;
   if (state->encoder_control->cfg->mv_rdo) {
     get_mvd_cost = kvz_get_mvd_coding_cost_cabac;
   }