diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 35ed2623e7..76369bac3f 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -740,6 +740,7 @@ AVOutputFormat matroska_muxer = {
     mkv_write_packet,
     mkv_write_trailer,
     .codec_tag = (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
+    .subtitle_codec = CODEC_ID_TEXT,
 };
 
 AVOutputFormat matroska_audio_muxer = {