diff --git a/libavcodec/ra144.c b/libavcodec/ra144.c
index 35b7921ec4..9baa06850f 100644
--- a/libavcodec/ra144.c
+++ b/libavcodec/ra144.c
@@ -1503,8 +1503,8 @@ const int16_t * const ff_lpc_refl_cb[10]={
     lpc_refl_cb6, lpc_refl_cb7, lpc_refl_cb8, lpc_refl_cb9, lpc_refl_cb10
 };
 
-void ff_add_wav(int16_t *dest, int n, int skip_first, int *m, const int16_t *s1,
-                const int8_t *s2, const int8_t *s3)
+static void ff_add_wav(int16_t *dest, int n, int skip_first, int *m, const int16_t *s1,
+                       const int8_t *s2, const int8_t *s3)
 {
     int i;
     int v[3];
diff --git a/libavcodec/ra144.h b/libavcodec/ra144.h
index 11c66a46e0..722b42e68a 100644
--- a/libavcodec/ra144.h
+++ b/libavcodec/ra144.h
@@ -56,8 +56,6 @@ typedef struct {
     uint16_t adapt_cb[146+2];
 } RA144Context;
 
-void ff_add_wav(int16_t *dest, int n, int skip_first, int *m, const int16_t *s1,
-                const int8_t *s2, const int8_t *s3);
 void ff_copy_and_dup(int16_t *target, const int16_t *source, int offset);
 int ff_eval_refl(int *refl, const int16_t *coefs, AVCodecContext *avctx);
 void ff_eval_coefs(int *coefs, const int *refl);