diff --git a/libavcodec/iirfilter.c b/libavcodec/iirfilter.c
index cd5bbc943a..900893d2ff 100644
--- a/libavcodec/iirfilter.c
+++ b/libavcodec/iirfilter.c
@@ -287,10 +287,21 @@ void ff_iir_filter(const struct FFIIRFilterCoeffs *c,
     }
 }
 
-void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
-                       struct FFIIRFilterState *s, int size,
-                       const float *src, ptrdiff_t sstep,
-                       float *dst, ptrdiff_t dstep)
+/**
+ * Perform IIR filtering on floating-point input samples.
+ *
+ * @param coeffs pointer to filter coefficients
+ * @param state  pointer to filter state
+ * @param size   input length
+ * @param src    source samples
+ * @param sstep  source stride
+ * @param dst    filtered samples (destination may be the same as input)
+ * @param dstep  destination stride
+ */
+static void iir_filter_flt(const struct FFIIRFilterCoeffs *c,
+                           struct FFIIRFilterState *s, int size,
+                           const float *src, ptrdiff_t sstep,
+                           float *dst, ptrdiff_t dstep)
 {
     if (c->order == 2) {
         FILTER_O2(float, FLT)
@@ -317,7 +328,7 @@ av_cold void ff_iir_filter_free_coeffsp(struct FFIIRFilterCoeffs **coeffsp)
 }
 
 void ff_iir_filter_init(FFIIRFilterContext *f) {
-    f->filter_flt = ff_iir_filter_flt;
+    f->filter_flt = iir_filter_flt;
 
     if (HAVE_MIPSFPU)
         ff_iir_filter_init_mips(f);
diff --git a/libavcodec/iirfilter.h b/libavcodec/iirfilter.h
index 5ffa1ce53a..d6b8fe2782 100644
--- a/libavcodec/iirfilter.h
+++ b/libavcodec/iirfilter.h
@@ -128,20 +128,4 @@ void ff_iir_filter_free_statep(struct FFIIRFilterState **state);
 void ff_iir_filter(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state,
                    int size, const int16_t *src, ptrdiff_t sstep, int16_t *dst, ptrdiff_t dstep);
 
-/**
- * Perform IIR filtering on floating-point input samples.
- *
- * @param coeffs pointer to filter coefficients
- * @param state  pointer to filter state
- * @param size   input length
- * @param src    source samples
- * @param sstep  source stride
- * @param dst    filtered samples (destination may be the same as input)
- * @param dstep  destination stride
- */
-void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *coeffs,
-                       struct FFIIRFilterState *state, int size,
-                       const float *src, ptrdiff_t sstep,
-                       float *dst, ptrdiff_t dstep);
-
 #endif /* AVCODEC_IIRFILTER_H */