diff --git a/libavformat/microdvdenc.c b/libavformat/microdvdenc.c
index 6639651e02..80e6fa8674 100644
--- a/libavformat/microdvdenc.c
+++ b/libavformat/microdvdenc.c
@@ -52,7 +52,7 @@ static int microdvd_write_packet(AVFormatContext *avf, AVPacket *pkt)
     else
         avio_printf(avf->pb, "{%"PRId64"}", pkt->pts + pkt->duration);
     avio_write(avf->pb, pkt->data, pkt->size);
-    avio_write(avf->pb, "\n", 1);
+    avio_w8(avf->pb, '\n');
     return 0;
 }