diff --git a/libavformat/microdvddec.c b/libavformat/microdvddec.c
index ca9086afe9..08e6fca09c 100644
--- a/libavformat/microdvddec.c
+++ b/libavformat/microdvddec.c
@@ -117,10 +117,11 @@ static int microdvd_read_header(AVFormatContext *s)
                 continue;
             }
             if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
-                st->codecpar->extradata = av_strdup(line + 11);
-                if (!st->codecpar->extradata)
-                    return AVERROR(ENOMEM);
-                st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;
+                int ret, size = strlen(line + 11);
+                ret = ff_alloc_extradata(st->codecpar, size);
+                if (ret < 0)
+                    return ret;
+                memcpy(st->codecpar->extradata, line + 11, size);
                 continue;
             }
         }
diff --git a/libavformat/microdvdenc.c b/libavformat/microdvdenc.c
index 04f475b645..6639651e02 100644
--- a/libavformat/microdvdenc.c
+++ b/libavformat/microdvdenc.c
@@ -36,6 +36,7 @@ static int microdvd_write_header(struct AVFormatContext *s)
     if (par->extradata && par->extradata_size > 0) {
         avio_write(s->pb, "{DEFAULT}{}", 11);
         avio_write(s->pb, par->extradata, par->extradata_size);
+        avio_w8(s->pb, '\n');
         avio_flush(s->pb);
     }
 
diff --git a/tests/ref/fate/sub-microdvd-remux b/tests/ref/fate/sub-microdvd-remux
index a71da99031..92ff233f56 100644
Binary files a/tests/ref/fate/sub-microdvd-remux and b/tests/ref/fate/sub-microdvd-remux differ