diff --git a/subprojects/gst-plugins-good/gst/matroska/matroska-demux.c b/subprojects/gst-plugins-good/gst/matroska/matroska-demux.c
index ef51dca298..64cc6be60b 100644
--- a/subprojects/gst-plugins-good/gst/matroska/matroska-demux.c
+++ b/subprojects/gst-plugins-good/gst/matroska/matroska-demux.c
@@ -6621,7 +6621,8 @@ gst_matroska_demux_video_caps (GstMatroskaTrackVideoContext *
       gst_caps_set_simple (caps, "codec-alpha", G_TYPE_BOOLEAN, TRUE, NULL);
     *codec_name = g_strdup_printf ("On2 VP9");
   } else if (!strcmp (codec_id, GST_MATROSKA_CODEC_ID_VIDEO_AV1)) {
-    caps = gst_caps_new_empty_simple ("video/x-av1");
+    caps = gst_caps_new_simple ("video/x-av1",
+        "alignment", G_TYPE_STRING, "tu", NULL);
     if (data) {
       GstBuffer *priv;
 
diff --git a/subprojects/gst-plugins-good/gst/matroska/matroska-mux.c b/subprojects/gst-plugins-good/gst/matroska/matroska-mux.c
index 189f4eea21..0147de216a 100644
--- a/subprojects/gst-plugins-good/gst/matroska/matroska-mux.c
+++ b/subprojects/gst-plugins-good/gst/matroska/matroska-mux.c
@@ -146,7 +146,7 @@ static GstStaticPadTemplate videosink_templ =
         "video/x-prores, "
         COMMON_VIDEO_CAPS "; "
         "video/x-wmv, " "wmvversion = (int) [ 1, 3 ], " COMMON_VIDEO_CAPS "; "
-        "video/x-av1, " COMMON_VIDEO_CAPS ";"
+        "video/x-av1, " "alignment = (string) \"tu\", " COMMON_VIDEO_CAPS ";"
         "video/x-ffv, ffversion = (int) 1, " COMMON_VIDEO_CAPS)
     );