diff --git a/libavformat/gxfenc.c b/libavformat/gxfenc.c
index a6f4b7260e..b20a8420eb 100644
--- a/libavformat/gxfenc.c
+++ b/libavformat/gxfenc.c
@@ -550,9 +550,9 @@ static int gxf_write_umf_media_description(AVFormatContext *s)
         put_le32(pb, 0); /* attributes rw, ro */
         put_le32(pb, 0); /* mark in */
         put_le32(pb, gxf->nb_fields); /* mark out */
-        put_buffer(pb, ES_NAME_PATTERN, sizeof(ES_NAME_PATTERN));
+        put_buffer(pb, ES_NAME_PATTERN, strlen(ES_NAME_PATTERN));
         put_be16(pb, sc->media_info);
-        for (j = sizeof(ES_NAME_PATTERN)+2; j < 88; j++)
+        for (j = strlen(ES_NAME_PATTERN)+2; j < 88; j++)
             put_byte(pb, 0);
         put_le32(pb, sc->track_type);
         put_le32(pb, sc->sample_rate);
diff --git a/tests/ref/lavf/gxf b/tests/ref/lavf/gxf
index d147bc47b7..5dc3ea7d6a 100644
--- a/tests/ref/lavf/gxf
+++ b/tests/ref/lavf/gxf
@@ -1,3 +1,3 @@
-b52bf18b403ac9a0d12048b2f66cb24c *./tests/data/lavf/lavf.gxf
+5b9c8da067585aeb04e5fb31e021cbfd *./tests/data/lavf/lavf.gxf
 796392 ./tests/data/lavf/lavf.gxf
 ./tests/data/lavf/lavf.gxf CRC=0xad9e86eb