diff --git a/libavformat/wtvenc.c b/libavformat/wtvenc.c
index a5692c1772..04e6cc22f8 100644
--- a/libavformat/wtvenc.c
+++ b/libavformat/wtvenc.c
@@ -28,6 +28,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavutil/avassert.h"
 #include "avformat.h"
+#include "avio_internal.h"
 #include "internal.h"
 #include "wtv.h"
 #include "asf.h"
@@ -127,12 +128,7 @@ typedef struct {
     WTVHeaderWriteFunc *write_header;
 } WTVRootEntryTable;
 
-static int write_pad(AVIOContext *pb, int size)
-{
-    for (; size > 0; size--)
-        avio_w8(pb, 0);
-    return 0;
-}
+#define write_pad(pb, size) ffio_fill(pb, 0, size)
 
 static const ff_asf_guid *get_codec_guid(enum AVCodecID id, const AVCodecGuid *av_guid)
 {