diff --git a/decoder/ixheaacd_api.c b/decoder/ixheaacd_api.c
index d77627f..68afd8f 100644
--- a/decoder/ixheaacd_api.c
+++ b/decoder/ixheaacd_api.c
@@ -168,7 +168,7 @@ IA_ERRORCODE ixheaacd_dec_mem_api(
   return IA_NO_ERROR;
 }
 
-PLATFORM_INLINE VOID
+static PLATFORM_INLINE VOID
 ixheaacd_init_sbr_tables(ia_sbr_tables_struct *ptr_sbr_tables) {
   ptr_sbr_tables->env_calc_tables_ptr =
       (ia_env_calc_tables_struct *)&ixheaacd_aac_dec_env_calc_tables;
diff --git a/decoder/ixheaacd_env_calc.c b/decoder/ixheaacd_env_calc.c
index 26590c4..2cedba7 100644
--- a/decoder/ixheaacd_env_calc.c
+++ b/decoder/ixheaacd_env_calc.c
@@ -989,11 +989,11 @@ VOID ixheaacd_equalize_filt_buff_exp(WORD16 *ptr_filt_buf, WORD16 *nrg_gain,
   }
 }
 
-PLATFORM_INLINE VOID ixheaacd_filt_buf_update(WORD16 *ptr_filt_buf,
-                                              WORD16 *ptr_filt_buf_noise,
-                                              WORD16 *nrg_gain,
-                                              WORD16 *noise_level_mant,
-                                              WORD32 num_sub_bands) {
+static PLATFORM_INLINE VOID ixheaacd_filt_buf_update(WORD16 *ptr_filt_buf,
+                                                     WORD16 *ptr_filt_buf_noise,
+                                                     WORD16 *nrg_gain,
+                                                     WORD16 *noise_level_mant,
+                                                     WORD32 num_sub_bands) {
   WORD32 k;
   WORD32 temp1, temp2;
 
diff --git a/decoder/ixheaacd_env_calc.h b/decoder/ixheaacd_env_calc.h
index b4a581d..7941ab3 100644
--- a/decoder/ixheaacd_env_calc.h
+++ b/decoder/ixheaacd_env_calc.h
@@ -54,11 +54,11 @@ PLATFORM_INLINE VOID ixheaacd_equalize_filt_buff_exp(WORD16 *ptr_filt_buf,
                                                      WORD16 *nrg_gain_mant,
                                                      WORD32 subbands);
 
-PLATFORM_INLINE VOID ixheaacd_filt_buf_update(WORD16 *filt_buf_mant,
-                                              WORD16 *ptr_filt_buf_noise,
-                                              WORD16 *nrg_gain_mant,
-                                              WORD16 *noise_level_mant,
-                                              WORD32 num_sub_bands);
+static PLATFORM_INLINE VOID ixheaacd_filt_buf_update(WORD16 *filt_buf_mant,
+                                                     WORD16 *ptr_filt_buf_noise,
+                                                     WORD16 *nrg_gain_mant,
+                                                     WORD16 *noise_level_mant,
+                                                     WORD32 num_sub_bands);
 
 VOID ixheaacd_noise_level_rescaling(WORD16 *noise_level_mant, WORD32 diff,
                                     WORD32 num_sub_bands,
@@ -179,11 +179,6 @@ VOID ixheaacd_subbandgain_calc(WORD16 e_orig_mant_matrix, WORD16 tmp_noise_mant,
                                WORD16 *ptr_noise_floor_mant,
                                WORD16 *ptr_nrg_sine_m,
                                ixheaacd_misc_tables *pstr_common_tables);
-PLATFORM_INLINE VOID ixheaacd_filt_buf_update(WORD16 *ptr_filt_buf,
-                                              WORD16 *ptr_filt_buf_noise,
-                                              WORD16 *nrg_gain,
-                                              WORD16 *noise_level_mant,
-                                              WORD32 num_sub_bands);
 
 PLATFORM_INLINE VOID ixheaacd_equalize_filt_buff_exp(WORD16 *ptr_filt_buf,
                                                      WORD16 *nrg_gain,