diff --git a/libavcodec/fft.c b/libavcodec/fft.c
index 81765510e3..3fd4d279cb 100644
--- a/libavcodec/fft.c
+++ b/libavcodec/fft.c
@@ -53,6 +53,9 @@ COSTABLE_CONST FFTSample * const ff_cos_tabs[] = {
     ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
 };
 
+static void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
+static void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
+
 static int split_radix_permutation(int i, int n, int inverse)
 {
     int m;
@@ -120,7 +123,7 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
     return -1;
 }
 
-void ff_fft_permute_c(FFTContext *s, FFTComplex *z)
+static void ff_fft_permute_c(FFTContext *s, FFTComplex *z)
 {
     int j, np;
     const uint16_t *revtab = s->revtab;
@@ -289,7 +292,7 @@ static void (* const fft_dispatch[])(FFTComplex*) = {
     fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
 };
 
-void ff_fft_calc_c(FFTContext *s, FFTComplex *z)
+static void ff_fft_calc_c(FFTContext *s, FFTComplex *z)
 {
     fft_dispatch[s->nbits-2](z);
 }
diff --git a/libavcodec/fft.h b/libavcodec/fft.h
index eb6714fe95..37cbfbf6a1 100644
--- a/libavcodec/fft.h
+++ b/libavcodec/fft.h
@@ -106,8 +106,6 @@ extern SINTABLE(65536);
  * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
  */
 int ff_fft_init(FFTContext *s, int nbits, int inverse);
-void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
-void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
 
 void ff_fft_init_altivec(FFTContext *s);
 void ff_fft_init_mmx(FFTContext *s);