diff --git a/demux/demux_mkv.c b/demux/demux_mkv.c
index 4ffe804faf..9545cb161b 100644
--- a/demux/demux_mkv.c
+++ b/demux/demux_mkv.c
@@ -1484,8 +1484,10 @@ static int demux_mkv_open_video(demuxer_t *demuxer, mkv_track_t *track)
     }
 
     const char *codec = sh_v->codec ? sh_v->codec : "";
-    if (!strcmp(codec, "mjpeg"))
+    if (!strcmp(codec, "mjpeg")) {
         sh_v->codec_tag = MKTAG('m', 'j', 'p', 'g');
+        track->require_keyframes = true;
+    }
 
     if (extradata_size > 0x1000000) {
         MP_WARN(demuxer, "Invalid CodecPrivate\n");