diff --git a/tests/fate/matroska.mak b/tests/fate/matroska.mak
index 63e81f121b..39137ad4be 100644
--- a/tests/fate/matroska.mak
+++ b/tests/fate/matroska.mak
@@ -49,6 +49,12 @@ FATE_MATROSKA-$(call ALLYES, FLAC_DECODER FLAC_ENCODER FLAC_PARSER \
 fate-matroska-flac-extradata-update: CMD = transcode matroska $(TARGET_SAMPLES)/mkv/flac_channel_layouts.mka \
                                            matroska "-map 0 -map 0:0 -c flac -frames:a:2 8" "-map 0 -c copy"
 
+# This tests that the Matroska/WebM muxer writes the AV1 CodecPrivate
+# via extradata obtained from packet side data. It also tests that
+# the aspect ratio is only written with pixels as DisplayUnit for WebM.
+FATE_MATROSKA-$(call REMUX, WEBM MATROSKA, IVF_DEMUXER AV1_PARSER EXTRACT_EXTRADATA_BSF) += fate-webm-av1-extradata-update
+fate-webm-av1-extradata-update: CMD = transcode ivf $(TARGET_SAMPLES)/av1/decode_model.ivf webm "-c copy -bsf extract_extradata -sar 3:1" "-c copy" "" "" "-nofind_stream_info" "-nofind_stream_info"
+
 # This test tests demuxing Vorbis and chapters from ogg and muxing it in and
 # demuxing it from Matroska/WebM. It furthermore tests the WebM muxer, in
 # particular its DASH mode. Finally, it tests writing the Cues at the front.
diff --git a/tests/ref/fate/webm-av1-extradata-update b/tests/ref/fate/webm-av1-extradata-update
new file mode 100644
index 0000000000..9dd2056e0e
--- /dev/null
+++ b/tests/ref/fate/webm-av1-extradata-update
@@ -0,0 +1,32 @@
+fbf3091fdf05b2856c578e7c948d68c3 *tests/data/fate/webm-av1-extradata-update.webm
+23048 tests/data/fate/webm-av1-extradata-update.webm
+#extradata 0:       35, 0x527207cd
+#tb 0: 1/1000
+#media_type 0: video
+#codec_id 0: av1
+#dimensions 0: 240x100
+#sar 0: 3/1
+0,          0,          0,        0,     8168, 0x1851ab62
+0,         42,         42,        0,     7040, 0x967788f9, F=0x0
+0,         83,         83,        0,        4, 0x01f400e2, F=0x0
+0,        125,        125,        0,       48, 0x49ad107e, F=0x0
+0,        167,        167,        0,        4, 0x021c00fa, F=0x0
+0,        208,        208,        0,      279, 0x69728439, F=0x0
+0,        250,        250,        0,        4, 0x01c400d2, F=0x0
+0,        292,        292,        0,       63, 0x9bbf1836, F=0x0
+0,        333,        333,        0,        4, 0x026c012a, F=0x0
+0,        375,        375,        0,     1065, 0xce2003ac, F=0x0
+0,        417,        417,        0,        4, 0x019400c2, F=0x0
+0,        458,        458,        0,       52, 0x7a0112f1, F=0x0
+0,        500,        500,        0,        4, 0x021c010a, F=0x0
+0,        542,        542,        0,      689, 0x1e8b49e7, F=0x0
+0,        583,        583,        0,        4, 0x01e400f2, F=0x0
+0,        625,        625,        0,      209, 0x124c6790, F=0x0
+0,        667,        667,        0,       42, 0xea690e31, F=0x0
+0,        708,        708,        0,     3521, 0xd76ee284, F=0x0
+0,        750,        750,        0,       63, 0x4572188f, F=0x0
+0,        792,        792,        0,      386, 0xb078c259, F=0x0
+0,        833,        833,        0,      178, 0x1ebb5121, F=0x0
+0,        875,        875,        0,       60, 0x729317f7, F=0x0
+0,        917,        917,        0,       40, 0xad970a66, F=0x0
+0,        958,        958,        0,       61, 0xcc0d1a20, F=0x0