diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index 0af14b5..f276222 100644
--- a/src/mp4box/mod.rs
+++ b/src/mp4box/mod.rs
@@ -86,6 +86,7 @@ pub(crate) mod mp4a;
 pub(crate) mod mvex;
 pub(crate) mod mvhd;
 pub(crate) mod smhd;
+pub(crate) mod soun;
 pub(crate) mod stbl;
 pub(crate) mod stco;
 pub(crate) mod stsc;
@@ -198,7 +199,8 @@ boxtype! {
     DayBox => 0xa9646179,
     CovrBox => 0x636f7672,
     DescBox => 0x64657363,
-    WideBox => 0x77696465
+    WideBox => 0x77696465,
+    SounBox => 0x736F756E
 }
 
 pub trait Mp4Box: Sized {
diff --git a/src/mp4box/soun.rs b/src/mp4box/soun.rs
new file mode 100644
index 0000000..e2b79c9
--- /dev/null
+++ b/src/mp4box/soun.rs
@@ -0,0 +1,32 @@
+use serde::Serialize;
+
+use crate::mp4box::*;
+
+// for opus
+// https://opus-codec.org/docs/opus_in_isobmff.html
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct SounBox {}
+
+impl Default for SounBox {
+    fn default() -> Self {
+        Self {}
+    }
+}
+
+impl Mp4Box for SounBox {
+    fn box_type(&self) -> BoxType {
+        BoxType::SounBox
+    }
+
+    fn box_size(&self) -> u64 {
+        todo!()
+    }
+
+    fn to_json(&self) -> Result<String> {
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
+    }
+
+    fn summary(&self) -> Result<String> {
+        todo!()
+    }
+}