diff --git a/src/libavcodec/from_lavc_vid_conv.c b/src/libavcodec/from_lavc_vid_conv.c
index 6521e8a5b..9e16d439e 100644
--- a/src/libavcodec/from_lavc_vid_conv.c
+++ b/src/libavcodec/from_lavc_vid_conv.c
@@ -113,6 +113,8 @@ static void rgb24_to_uyvy(char * __restrict dst_buffer, AVFrame * __restrict fra
         }
 }
 
+static void memcpy_data(char * __restrict dst_buffer, AVFrame * __restrict frame,
+                int width, int height, int pitch, const int * __restrict rgb_shift) ATTRIBUTE(unused);
 static void memcpy_data(char * __restrict dst_buffer, AVFrame * __restrict frame,
                 int width, int height, int pitch, const int * __restrict rgb_shift)
 {