diff --git a/CHANGES.md b/CHANGES.md
index cb62c440..28b00780 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,6 +11,8 @@
 
 ## develop
 
+- [ADD] `Mp4MediaStream` の対応コーデックに AV1 を追加する
+  - @sile
 - [ADD] `Mp4MediaStream` の対応コーデックに VP9 を追加する
   - @sile
 - [ADD] `Mp4MediaStream` の対応コーデックに VP8 を追加する
diff --git a/packages/mp4-media-stream/README.md b/packages/mp4-media-stream/README.md
index ed8c009b..681b567e 100644
--- a/packages/mp4-media-stream/README.md
+++ b/packages/mp4-media-stream/README.md
@@ -34,6 +34,7 @@ video.srcObject = stream
   - H.264
   - VP8
   - VP9
+  - AV1
 - 音声:
   - AAC
   - Opus
diff --git a/packages/mp4-media-stream/wasm/src/mp4.rs b/packages/mp4-media-stream/wasm/src/mp4.rs
index 4ca941e8..9867d3dd 100644
--- a/packages/mp4-media-stream/wasm/src/mp4.rs
+++ b/packages/mp4-media-stream/wasm/src/mp4.rs
@@ -5,8 +5,8 @@ use serde::Serialize;
 use shiguredo_mp4::{
     aux::SampleTableAccessor,
     boxes::{
-        Avc1Box, FtypBox, HdlrBox, IgnoredBox, MoovBox, Mp4aBox, OpusBox, SampleEntry, StblBox,
-        TrakBox, Vp08Box, Vp09Box,
+        Av01Box, Avc1Box, FtypBox, HdlrBox, IgnoredBox, MoovBox, Mp4aBox, OpusBox, SampleEntry,
+        StblBox, TrakBox, Vp08Box, Vp09Box,
     },
     BaseBox, Decode, Either, Encode,
 };
@@ -61,6 +61,35 @@ impl VideoDecoderConfig {
             coded_height: b.visual.height,
         }
     }
+
+    pub fn from_av01_box(b: &Av01Box) -> Self {
+        Self {
+            // https://aomediacodec.github.io/av1-isobmff/#codecsparam
+            codec: format!(
+                "av01.{}.{:02}{}.{:02}",
+                b.av1c_box.seq_profile.get(),
+                b.av1c_box.seq_level_idx_0.get(),
+                if b.av1c_box.seq_tier_0.get() == 0 {
+                    'M'
+                } else {
+                    'H'
+                },
+                match (
+                    b.av1c_box.seq_profile.get(),
+                    b.av1c_box.high_bitdepth.get(),
+                    b.av1c_box.twelve_bit.get()
+                ) {
+                    (2, 1, 1) => 12,
+                    (2, 1, 0) => 10,
+                    (_, 1, _) => 10,
+                    (_, _, _) => 8,
+                }
+            ),
+            description: Vec::new(),
+            coded_width: b.visual.width,
+            coded_height: b.visual.height,
+        }
+    }
 }
 
 #[derive(Debug, Serialize)]
@@ -136,6 +165,7 @@ impl Track {
             Some(SampleEntry::Avc1(_)) => (),
             Some(SampleEntry::Vp08(_)) => (),
             Some(SampleEntry::Vp09(_)) => (),
+            Some(SampleEntry::Av01(_)) => (),
             Some(SampleEntry::Opus(_)) => (),
             Some(SampleEntry::Mp4a(_)) => (),
             Some(b) => {
@@ -232,6 +262,9 @@ impl Mp4 {
                     SampleEntry::Vp09(b) => {
                         video_configs.push(VideoDecoderConfig::from_vp09_box(b));
                     }
+                    SampleEntry::Av01(b) => {
+                        video_configs.push(VideoDecoderConfig::from_av01_box(b));
+                    }
                     SampleEntry::Opus(b) => {
                         audio_configs.push(AudioDecoderConfig::from_opus_box(b));
                     }
diff --git a/packages/mp4-media-stream/wasm/src/player.rs b/packages/mp4-media-stream/wasm/src/player.rs
index 3e103076..10728463 100644
--- a/packages/mp4-media-stream/wasm/src/player.rs
+++ b/packages/mp4-media-stream/wasm/src/player.rs
@@ -188,6 +188,10 @@ impl TrackPlayer {
                 let config = VideoDecoderConfig::from_vp09_box(b);
                 WasmApi::create_video_decoder(self.player_id, config).await
             }
+            SampleEntry::Av01(b) => {
+                let config = VideoDecoderConfig::from_av01_box(b);
+                WasmApi::create_video_decoder(self.player_id, config).await
+            }
             SampleEntry::Opus(b) => {
                 let config = AudioDecoderConfig::from_opus_box(b);
                 WasmApi::create_audio_decoder(self.player_id, config).await