From 6a6e746c3f827e439d3dc4dbe41d2b2037973f49 Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 09:47:17 -0400
Subject: [PATCH 1/8] wip(mp4box): bin adding box for opus

---
 src/mp4box/mod.rs  |  4 +++-
 src/mp4box/soun.rs | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 src/mp4box/soun.rs

diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index 0af14b5f..f2762225 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 00000000..e2b79c9f
--- /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!()
+    }
+}

From 3e23adae7fd0d3a8b4e6e85d70800b06c4feb319 Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 09:49:32 -0400
Subject: [PATCH 2/8] fix(mp4box): remove unwrap() in to_json() for Mp4Box
 implementation.

---
 src/mp4box/avc1.rs | 4 ++--
 src/mp4box/co64.rs | 2 +-
 src/mp4box/ctts.rs | 2 +-
 src/mp4box/data.rs | 2 +-
 src/mp4box/dinf.rs | 6 +++---
 src/mp4box/edts.rs | 2 +-
 src/mp4box/elst.rs | 2 +-
 src/mp4box/emsg.rs | 2 +-
 src/mp4box/ftyp.rs | 2 +-
 src/mp4box/hdlr.rs | 2 +-
 src/mp4box/hev1.rs | 4 ++--
 src/mp4box/ilst.rs | 2 +-
 src/mp4box/mdhd.rs | 2 +-
 src/mp4box/mdia.rs | 2 +-
 src/mp4box/mehd.rs | 2 +-
 src/mp4box/meta.rs | 2 +-
 src/mp4box/mfhd.rs | 2 +-
 src/mp4box/minf.rs | 2 +-
 src/mp4box/moof.rs | 2 +-
 src/mp4box/moov.rs | 2 +-
 src/mp4box/mp4a.rs | 4 ++--
 src/mp4box/mvex.rs | 2 +-
 src/mp4box/mvhd.rs | 2 +-
 src/mp4box/smhd.rs | 2 +-
 src/mp4box/stbl.rs | 2 +-
 src/mp4box/stco.rs | 2 +-
 src/mp4box/stsc.rs | 2 +-
 src/mp4box/stsd.rs | 2 +-
 src/mp4box/stss.rs | 2 +-
 src/mp4box/stsz.rs | 2 +-
 src/mp4box/stts.rs | 2 +-
 src/mp4box/tfdt.rs | 2 +-
 src/mp4box/tfhd.rs | 2 +-
 src/mp4box/tkhd.rs | 2 +-
 src/mp4box/traf.rs | 2 +-
 src/mp4box/trak.rs | 2 +-
 src/mp4box/trex.rs | 2 +-
 src/mp4box/trun.rs | 2 +-
 src/mp4box/tx3g.rs | 2 +-
 src/mp4box/udta.rs | 2 +-
 src/mp4box/vmhd.rs | 2 +-
 src/mp4box/vp09.rs | 2 +-
 src/mp4box/vpcc.rs | 2 +-
 43 files changed, 48 insertions(+), 48 deletions(-)

diff --git a/src/mp4box/avc1.rs b/src/mp4box/avc1.rs
index 71741228..7226d5d9 100644
--- a/src/mp4box/avc1.rs
+++ b/src/mp4box/avc1.rs
@@ -68,7 +68,7 @@ impl Mp4Box for Avc1Box {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
@@ -200,7 +200,7 @@ impl Mp4Box for AvcCBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/co64.rs b/src/mp4box/co64.rs
index 978137e9..c6f77d30 100644
--- a/src/mp4box/co64.rs
+++ b/src/mp4box/co64.rs
@@ -34,7 +34,7 @@ impl Mp4Box for Co64Box {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/ctts.rs b/src/mp4box/ctts.rs
index 673e8c92..7316c9b0 100644
--- a/src/mp4box/ctts.rs
+++ b/src/mp4box/ctts.rs
@@ -40,7 +40,7 @@ impl Mp4Box for CttsBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/data.rs b/src/mp4box/data.rs
index 19b5c77c..f49631e8 100644
--- a/src/mp4box/data.rs
+++ b/src/mp4box/data.rs
@@ -37,7 +37,7 @@ impl Mp4Box for DataBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/dinf.rs b/src/mp4box/dinf.rs
index 46698c98..ad78a0f7 100644
--- a/src/mp4box/dinf.rs
+++ b/src/mp4box/dinf.rs
@@ -28,7 +28,7 @@ impl Mp4Box for DinfBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
@@ -132,7 +132,7 @@ impl Mp4Box for DrefBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
@@ -249,7 +249,7 @@ impl Mp4Box for UrlBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/edts.rs b/src/mp4box/edts.rs
index 9077bb17..5ab5962a 100644
--- a/src/mp4box/edts.rs
+++ b/src/mp4box/edts.rs
@@ -37,7 +37,7 @@ impl Mp4Box for EdtsBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/elst.rs b/src/mp4box/elst.rs
index 297fb63a..79267e56 100644
--- a/src/mp4box/elst.rs
+++ b/src/mp4box/elst.rs
@@ -48,7 +48,7 @@ impl Mp4Box for ElstBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/emsg.rs b/src/mp4box/emsg.rs
index f68ba3af..c03bcae8 100644
--- a/src/mp4box/emsg.rs
+++ b/src/mp4box/emsg.rs
@@ -49,7 +49,7 @@ impl Mp4Box for EmsgBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/ftyp.rs b/src/mp4box/ftyp.rs
index 789cd4ef..36c8e360 100644
--- a/src/mp4box/ftyp.rs
+++ b/src/mp4box/ftyp.rs
@@ -31,7 +31,7 @@ impl Mp4Box for FtypBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/hdlr.rs b/src/mp4box/hdlr.rs
index 1ff559e0..99455ceb 100644
--- a/src/mp4box/hdlr.rs
+++ b/src/mp4box/hdlr.rs
@@ -32,7 +32,7 @@ impl Mp4Box for HdlrBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/hev1.rs b/src/mp4box/hev1.rs
index 3a8cfead..c0731c6e 100644
--- a/src/mp4box/hev1.rs
+++ b/src/mp4box/hev1.rs
@@ -68,7 +68,7 @@ impl Mp4Box for Hev1Box {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
@@ -181,7 +181,7 @@ impl Mp4Box for HvcCBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/ilst.rs b/src/mp4box/ilst.rs
index d0292a31..5de336af 100644
--- a/src/mp4box/ilst.rs
+++ b/src/mp4box/ilst.rs
@@ -37,7 +37,7 @@ impl Mp4Box for IlstBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mdhd.rs b/src/mp4box/mdhd.rs
index 31c65a80..ee4e753e 100644
--- a/src/mp4box/mdhd.rs
+++ b/src/mp4box/mdhd.rs
@@ -58,7 +58,7 @@ impl Mp4Box for MdhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mdia.rs b/src/mp4box/mdia.rs
index 423bf72e..3d1e1599 100644
--- a/src/mp4box/mdia.rs
+++ b/src/mp4box/mdia.rs
@@ -31,7 +31,7 @@ impl Mp4Box for MdiaBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mehd.rs b/src/mp4box/mehd.rs
index 63c0246e..0bab2a5d 100644
--- a/src/mp4box/mehd.rs
+++ b/src/mp4box/mehd.rs
@@ -38,7 +38,7 @@ impl Mp4Box for MehdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/meta.rs b/src/mp4box/meta.rs
index df57c775..a3fe74d5 100644
--- a/src/mp4box/meta.rs
+++ b/src/mp4box/meta.rs
@@ -57,7 +57,7 @@ impl Mp4Box for MetaBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mfhd.rs b/src/mp4box/mfhd.rs
index 7bc2f724..067aa222 100644
--- a/src/mp4box/mfhd.rs
+++ b/src/mp4box/mfhd.rs
@@ -41,7 +41,7 @@ impl Mp4Box for MfhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/minf.rs b/src/mp4box/minf.rs
index 5ea853b4..2ec88786 100644
--- a/src/mp4box/minf.rs
+++ b/src/mp4box/minf.rs
@@ -45,7 +45,7 @@ impl Mp4Box for MinfBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/moof.rs b/src/mp4box/moof.rs
index 20c35653..89bcf518 100644
--- a/src/mp4box/moof.rs
+++ b/src/mp4box/moof.rs
@@ -36,7 +36,7 @@ impl Mp4Box for MoofBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/moov.rs b/src/mp4box/moov.rs
index ac19381a..194c9ae0 100644
--- a/src/mp4box/moov.rs
+++ b/src/mp4box/moov.rs
@@ -52,7 +52,7 @@ impl Mp4Box for MoovBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mp4a.rs b/src/mp4box/mp4a.rs
index e4d6a45c..e6c2a636 100644
--- a/src/mp4box/mp4a.rs
+++ b/src/mp4box/mp4a.rs
@@ -61,7 +61,7 @@ impl Mp4Box for Mp4aBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
@@ -170,7 +170,7 @@ impl Mp4Box for EsdsBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mvex.rs b/src/mp4box/mvex.rs
index 8be683b8..31a9eabd 100644
--- a/src/mp4box/mvex.rs
+++ b/src/mp4box/mvex.rs
@@ -30,7 +30,7 @@ impl Mp4Box for MvexBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/mvhd.rs b/src/mp4box/mvhd.rs
index 462a29b3..d0593b17 100644
--- a/src/mp4box/mvhd.rs
+++ b/src/mp4box/mvhd.rs
@@ -67,7 +67,7 @@ impl Mp4Box for MvhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/smhd.rs b/src/mp4box/smhd.rs
index cab7e4bb..f0a34c23 100644
--- a/src/mp4box/smhd.rs
+++ b/src/mp4box/smhd.rs
@@ -43,7 +43,7 @@ impl Mp4Box for SmhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stbl.rs b/src/mp4box/stbl.rs
index ef8433b4..46199c12 100644
--- a/src/mp4box/stbl.rs
+++ b/src/mp4box/stbl.rs
@@ -64,7 +64,7 @@ impl Mp4Box for StblBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stco.rs b/src/mp4box/stco.rs
index a00da8f9..daa37e0b 100644
--- a/src/mp4box/stco.rs
+++ b/src/mp4box/stco.rs
@@ -34,7 +34,7 @@ impl Mp4Box for StcoBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stsc.rs b/src/mp4box/stsc.rs
index e5b444ef..25d75bcb 100644
--- a/src/mp4box/stsc.rs
+++ b/src/mp4box/stsc.rs
@@ -42,7 +42,7 @@ impl Mp4Box for StscBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stsd.rs b/src/mp4box/stsd.rs
index af947c6c..635ac892 100644
--- a/src/mp4box/stsd.rs
+++ b/src/mp4box/stsd.rs
@@ -59,7 +59,7 @@ impl Mp4Box for StsdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stss.rs b/src/mp4box/stss.rs
index dd9e552f..11b8d330 100644
--- a/src/mp4box/stss.rs
+++ b/src/mp4box/stss.rs
@@ -34,7 +34,7 @@ impl Mp4Box for StssBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stsz.rs b/src/mp4box/stsz.rs
index b07e7653..38855df2 100644
--- a/src/mp4box/stsz.rs
+++ b/src/mp4box/stsz.rs
@@ -36,7 +36,7 @@ impl Mp4Box for StszBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/stts.rs b/src/mp4box/stts.rs
index 82de6c50..66e76e54 100644
--- a/src/mp4box/stts.rs
+++ b/src/mp4box/stts.rs
@@ -40,7 +40,7 @@ impl Mp4Box for SttsBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/tfdt.rs b/src/mp4box/tfdt.rs
index ef928899..68e55e9e 100644
--- a/src/mp4box/tfdt.rs
+++ b/src/mp4box/tfdt.rs
@@ -37,7 +37,7 @@ impl Mp4Box for TfdtBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/tfhd.rs b/src/mp4box/tfhd.rs
index e67e5cb3..bc51684c 100644
--- a/src/mp4box/tfhd.rs
+++ b/src/mp4box/tfhd.rs
@@ -58,7 +58,7 @@ impl Mp4Box for TfhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/tkhd.rs b/src/mp4box/tkhd.rs
index d7bcfbe0..58b0f6a3 100644
--- a/src/mp4box/tkhd.rs
+++ b/src/mp4box/tkhd.rs
@@ -126,7 +126,7 @@ impl Mp4Box for TkhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/traf.rs b/src/mp4box/traf.rs
index 51f812d8..bdd5ffec 100644
--- a/src/mp4box/traf.rs
+++ b/src/mp4box/traf.rs
@@ -36,7 +36,7 @@ impl Mp4Box for TrafBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/trak.rs b/src/mp4box/trak.rs
index e8ae760f..e0c286a1 100644
--- a/src/mp4box/trak.rs
+++ b/src/mp4box/trak.rs
@@ -44,7 +44,7 @@ impl Mp4Box for TrakBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/trex.rs b/src/mp4box/trex.rs
index 2694fd65..2a458617 100644
--- a/src/mp4box/trex.rs
+++ b/src/mp4box/trex.rs
@@ -35,7 +35,7 @@ impl Mp4Box for TrexBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/trun.rs b/src/mp4box/trun.rs
index efbb2b09..793d53d0 100644
--- a/src/mp4box/trun.rs
+++ b/src/mp4box/trun.rs
@@ -69,7 +69,7 @@ impl Mp4Box for TrunBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/tx3g.rs b/src/mp4box/tx3g.rs
index d6963159..7edcc34d 100644
--- a/src/mp4box/tx3g.rs
+++ b/src/mp4box/tx3g.rs
@@ -62,7 +62,7 @@ impl Mp4Box for Tx3gBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/udta.rs b/src/mp4box/udta.rs
index 9daec179..3fb40b42 100644
--- a/src/mp4box/udta.rs
+++ b/src/mp4box/udta.rs
@@ -35,7 +35,7 @@ impl Mp4Box for UdtaBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/vmhd.rs b/src/mp4box/vmhd.rs
index 31f24b21..3eb8c9fa 100644
--- a/src/mp4box/vmhd.rs
+++ b/src/mp4box/vmhd.rs
@@ -39,7 +39,7 @@ impl Mp4Box for VmhdBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/vp09.rs b/src/mp4box/vp09.rs
index 0f88dd14..099339f7 100644
--- a/src/mp4box/vp09.rs
+++ b/src/mp4box/vp09.rs
@@ -75,7 +75,7 @@ impl Mp4Box for Vp09Box {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {
diff --git a/src/mp4box/vpcc.rs b/src/mp4box/vpcc.rs
index c9861c66..f3beaf2a 100644
--- a/src/mp4box/vpcc.rs
+++ b/src/mp4box/vpcc.rs
@@ -32,7 +32,7 @@ impl Mp4Box for VpccBox {
     }
 
     fn to_json(&self) -> Result<String> {
-        Ok(serde_json::to_string(&self).unwrap())
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
     }
 
     fn summary(&self) -> Result<String> {

From ff9e75922b4b3b539ab088be4dc2db922c0a2c9f Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 10:02:42 -0400
Subject: [PATCH 3/8] fix(reader): return Err instead of panic

---
 src/reader.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/reader.rs b/src/reader.rs
index 5a39eebb..45c64b17 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -116,8 +116,8 @@ impl<R: Read + Seek> Mp4Reader<R> {
 
         Ok(Mp4Reader {
             reader,
-            ftyp: ftyp.unwrap(),
-            moov: moov.unwrap(),
+            ftyp: ftyp.ok_or(crate::error::Error::BoxNotFound(BoxType::FtypBox))?,
+            moov: moov.ok_or(crate::error::Error::BoxNotFound(BoxType::MoovBox))?,
             moofs,
             emsgs,
             size,

From 0fdd2d16b49c7576443ea73dd19b5d94f26cb39c Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 11:52:19 -0400
Subject: [PATCH 4/8] chore(Mp4Box): use a trait function for to_json

---
 src/mp4box/avc1.rs |  8 --------
 src/mp4box/co64.rs |  4 ----
 src/mp4box/ctts.rs |  4 ----
 src/mp4box/data.rs |  4 ----
 src/mp4box/dinf.rs | 12 ------------
 src/mp4box/edts.rs |  4 ----
 src/mp4box/elst.rs |  4 ----
 src/mp4box/emsg.rs |  4 ----
 src/mp4box/ftyp.rs |  4 ----
 src/mp4box/hdlr.rs |  4 ----
 src/mp4box/hev1.rs |  8 --------
 src/mp4box/ilst.rs |  4 ----
 src/mp4box/mdhd.rs |  4 ----
 src/mp4box/mdia.rs |  4 ----
 src/mp4box/mehd.rs |  4 ----
 src/mp4box/meta.rs |  4 ----
 src/mp4box/mfhd.rs |  4 ----
 src/mp4box/minf.rs |  4 ----
 src/mp4box/mod.rs  |  8 +++++++-
 src/mp4box/moof.rs |  4 ----
 src/mp4box/moov.rs |  4 ----
 src/mp4box/mp4a.rs |  8 --------
 src/mp4box/mvex.rs |  4 ----
 src/mp4box/mvhd.rs |  4 ----
 src/mp4box/smhd.rs |  4 ----
 src/mp4box/soun.rs |  4 ----
 src/mp4box/stbl.rs |  4 ----
 src/mp4box/stco.rs |  4 ----
 src/mp4box/stsc.rs |  4 ----
 src/mp4box/stsd.rs |  4 ----
 src/mp4box/stss.rs |  4 ----
 src/mp4box/stsz.rs |  4 ----
 src/mp4box/stts.rs |  4 ----
 src/mp4box/tfdt.rs |  4 ----
 src/mp4box/tfhd.rs |  4 ----
 src/mp4box/tkhd.rs |  4 ----
 src/mp4box/traf.rs |  4 ----
 src/mp4box/trak.rs |  4 ----
 src/mp4box/trex.rs |  4 ----
 src/mp4box/trun.rs |  4 ----
 src/mp4box/tx3g.rs |  4 ----
 src/mp4box/udta.rs |  4 ----
 src/mp4box/vmhd.rs |  4 ----
 src/mp4box/vp09.rs |  4 ----
 src/mp4box/vpcc.rs |  4 ----
 45 files changed, 7 insertions(+), 197 deletions(-)

diff --git a/src/mp4box/avc1.rs b/src/mp4box/avc1.rs
index 7226d5d9..b2a514fe 100644
--- a/src/mp4box/avc1.rs
+++ b/src/mp4box/avc1.rs
@@ -67,10 +67,6 @@ impl Mp4Box for Avc1Box {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "data_reference_index={} width={} height={} frame_count={}",
@@ -199,10 +195,6 @@ impl Mp4Box for AvcCBox {
         size
     }
 
-    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> {
         let s = format!("avc_profile_indication={}", self.avc_profile_indication);
         Ok(s)
diff --git a/src/mp4box/co64.rs b/src/mp4box/co64.rs
index c6f77d30..4ab94fff 100644
--- a/src/mp4box/co64.rs
+++ b/src/mp4box/co64.rs
@@ -33,10 +33,6 @@ impl Mp4Box for Co64Box {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries_count={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/ctts.rs b/src/mp4box/ctts.rs
index 7316c9b0..7bad066e 100644
--- a/src/mp4box/ctts.rs
+++ b/src/mp4box/ctts.rs
@@ -39,10 +39,6 @@ impl Mp4Box for CttsBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries_count={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/data.rs b/src/mp4box/data.rs
index f49631e8..79ef769a 100644
--- a/src/mp4box/data.rs
+++ b/src/mp4box/data.rs
@@ -36,10 +36,6 @@ impl Mp4Box for DataBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("type={:?} len={}", self.data_type, self.data.len());
         Ok(s)
diff --git a/src/mp4box/dinf.rs b/src/mp4box/dinf.rs
index ad78a0f7..a6943c70 100644
--- a/src/mp4box/dinf.rs
+++ b/src/mp4box/dinf.rs
@@ -27,10 +27,6 @@ impl Mp4Box for DinfBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
@@ -131,10 +127,6 @@ impl Mp4Box for DrefBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
@@ -248,10 +240,6 @@ impl Mp4Box for UrlBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("location={}", self.location);
         Ok(s)
diff --git a/src/mp4box/edts.rs b/src/mp4box/edts.rs
index 5ab5962a..22f43ee7 100644
--- a/src/mp4box/edts.rs
+++ b/src/mp4box/edts.rs
@@ -36,10 +36,6 @@ impl Mp4Box for EdtsBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/elst.rs b/src/mp4box/elst.rs
index 79267e56..1182e2a8 100644
--- a/src/mp4box/elst.rs
+++ b/src/mp4box/elst.rs
@@ -47,10 +47,6 @@ impl Mp4Box for ElstBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("elst_entries={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/emsg.rs b/src/mp4box/emsg.rs
index c03bcae8..921dd4d8 100644
--- a/src/mp4box/emsg.rs
+++ b/src/mp4box/emsg.rs
@@ -48,10 +48,6 @@ impl Mp4Box for EmsgBox {
             + self.message_data.len() as u64
     }
 
-    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> {
         let s = format!("id={} value={}", self.id, self.value);
         Ok(s)
diff --git a/src/mp4box/ftyp.rs b/src/mp4box/ftyp.rs
index 36c8e360..dd35bb5a 100644
--- a/src/mp4box/ftyp.rs
+++ b/src/mp4box/ftyp.rs
@@ -30,10 +30,6 @@ impl Mp4Box for FtypBox {
         self.get_size()
     }
 
-    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> {
         let mut compatible_brands = Vec::new();
         for brand in self.compatible_brands.iter() {
diff --git a/src/mp4box/hdlr.rs b/src/mp4box/hdlr.rs
index 99455ceb..b5d9f5b1 100644
--- a/src/mp4box/hdlr.rs
+++ b/src/mp4box/hdlr.rs
@@ -31,10 +31,6 @@ impl Mp4Box for HdlrBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("handler_type={} name={}", self.handler_type, self.name);
         Ok(s)
diff --git a/src/mp4box/hev1.rs b/src/mp4box/hev1.rs
index c0731c6e..4472addb 100644
--- a/src/mp4box/hev1.rs
+++ b/src/mp4box/hev1.rs
@@ -67,10 +67,6 @@ impl Mp4Box for Hev1Box {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "data_reference_index={} width={} height={} frame_count={}",
@@ -180,10 +176,6 @@ impl Mp4Box for HvcCBox {
         HEADER_SIZE + 1
     }
 
-    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> {
         let s = format!("configuration_version={}", self.configuration_version);
         Ok(s)
diff --git a/src/mp4box/ilst.rs b/src/mp4box/ilst.rs
index 5de336af..9336b902 100644
--- a/src/mp4box/ilst.rs
+++ b/src/mp4box/ilst.rs
@@ -36,10 +36,6 @@ impl Mp4Box for IlstBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("item_count={}", self.items.len());
         Ok(s)
diff --git a/src/mp4box/mdhd.rs b/src/mp4box/mdhd.rs
index ee4e753e..bd63a875 100644
--- a/src/mp4box/mdhd.rs
+++ b/src/mp4box/mdhd.rs
@@ -57,10 +57,6 @@ impl Mp4Box for MdhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "creation_time={} timescale={} duration={} language={}",
diff --git a/src/mp4box/mdia.rs b/src/mp4box/mdia.rs
index 3d1e1599..ea4d647b 100644
--- a/src/mp4box/mdia.rs
+++ b/src/mp4box/mdia.rs
@@ -30,10 +30,6 @@ impl Mp4Box for MdiaBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/mehd.rs b/src/mp4box/mehd.rs
index 0bab2a5d..72db38a4 100644
--- a/src/mp4box/mehd.rs
+++ b/src/mp4box/mehd.rs
@@ -37,10 +37,6 @@ impl Mp4Box for MehdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("fragment_duration={}", self.fragment_duration);
         Ok(s)
diff --git a/src/mp4box/meta.rs b/src/mp4box/meta.rs
index a3fe74d5..ad441204 100644
--- a/src/mp4box/meta.rs
+++ b/src/mp4box/meta.rs
@@ -56,10 +56,6 @@ impl Mp4Box for MetaBox {
         self.get_size()
     }
 
-    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> {
         let s = match self {
             Self::Mdir { .. } => "hdlr=ilst".to_string(),
diff --git a/src/mp4box/mfhd.rs b/src/mp4box/mfhd.rs
index 067aa222..f1b0f9f9 100644
--- a/src/mp4box/mfhd.rs
+++ b/src/mp4box/mfhd.rs
@@ -40,10 +40,6 @@ impl Mp4Box for MfhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("sequence_number={}", self.sequence_number);
         Ok(s)
diff --git a/src/mp4box/minf.rs b/src/mp4box/minf.rs
index 2ec88786..6eb561fc 100644
--- a/src/mp4box/minf.rs
+++ b/src/mp4box/minf.rs
@@ -44,10 +44,6 @@ impl Mp4Box for MinfBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index f2762225..19578b17 100644
--- a/src/mp4box/mod.rs
+++ b/src/mp4box/mod.rs
@@ -57,6 +57,7 @@
 //!
 
 use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
+use serde::Serialize;
 use std::convert::TryInto;
 use std::io::{Read, Seek, SeekFrom, Write};
 
@@ -206,7 +207,12 @@ boxtype! {
 pub trait Mp4Box: Sized {
     fn box_type(&self) -> BoxType;
     fn box_size(&self) -> u64;
-    fn to_json(&self) -> Result<String>;
+    fn to_json(&self) -> Result<String>
+    where
+        Self: Serialize,
+    {
+        serde_json::to_string(&self).map_err(|e| crate::error::Error::IoError(e.into()))
+    }
     fn summary(&self) -> Result<String>;
 }
 
diff --git a/src/mp4box/moof.rs b/src/mp4box/moof.rs
index 89bcf518..e90c1f50 100644
--- a/src/mp4box/moof.rs
+++ b/src/mp4box/moof.rs
@@ -35,10 +35,6 @@ impl Mp4Box for MoofBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("trafs={}", self.trafs.len());
         Ok(s)
diff --git a/src/mp4box/moov.rs b/src/mp4box/moov.rs
index 194c9ae0..70578d97 100644
--- a/src/mp4box/moov.rs
+++ b/src/mp4box/moov.rs
@@ -51,10 +51,6 @@ impl Mp4Box for MoovBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("traks={}", self.traks.len());
         Ok(s)
diff --git a/src/mp4box/mp4a.rs b/src/mp4box/mp4a.rs
index e6c2a636..f8f411d5 100644
--- a/src/mp4box/mp4a.rs
+++ b/src/mp4box/mp4a.rs
@@ -60,10 +60,6 @@ impl Mp4Box for Mp4aBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "channel_count={} sample_size={} sample_rate={}",
@@ -169,10 +165,6 @@ impl Mp4Box for EsdsBox {
             + ESDescriptor::desc_size() as u64
     }
 
-    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> {
         Ok(String::new())
     }
diff --git a/src/mp4box/mvex.rs b/src/mp4box/mvex.rs
index 31a9eabd..6e269f7d 100644
--- a/src/mp4box/mvex.rs
+++ b/src/mp4box/mvex.rs
@@ -29,10 +29,6 @@ impl Mp4Box for MvexBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/mvhd.rs b/src/mp4box/mvhd.rs
index d0593b17..9bcd0db8 100644
--- a/src/mp4box/mvhd.rs
+++ b/src/mp4box/mvhd.rs
@@ -66,10 +66,6 @@ impl Mp4Box for MvhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "creation_time={} timescale={} duration={} rate={} volume={}, matrix={}, next_track_id={}",
diff --git a/src/mp4box/smhd.rs b/src/mp4box/smhd.rs
index f0a34c23..bc919e5c 100644
--- a/src/mp4box/smhd.rs
+++ b/src/mp4box/smhd.rs
@@ -42,10 +42,6 @@ impl Mp4Box for SmhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("balance={}", self.balance.value());
         Ok(s)
diff --git a/src/mp4box/soun.rs b/src/mp4box/soun.rs
index e2b79c9f..b2ddabab 100644
--- a/src/mp4box/soun.rs
+++ b/src/mp4box/soun.rs
@@ -22,10 +22,6 @@ impl Mp4Box for SounBox {
         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!()
     }
diff --git a/src/mp4box/stbl.rs b/src/mp4box/stbl.rs
index 46199c12..03dd819a 100644
--- a/src/mp4box/stbl.rs
+++ b/src/mp4box/stbl.rs
@@ -63,10 +63,6 @@ impl Mp4Box for StblBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/stco.rs b/src/mp4box/stco.rs
index daa37e0b..3ce39d9d 100644
--- a/src/mp4box/stco.rs
+++ b/src/mp4box/stco.rs
@@ -33,10 +33,6 @@ impl Mp4Box for StcoBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/stsc.rs b/src/mp4box/stsc.rs
index 25d75bcb..44834e44 100644
--- a/src/mp4box/stsc.rs
+++ b/src/mp4box/stsc.rs
@@ -41,10 +41,6 @@ impl Mp4Box for StscBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/stsd.rs b/src/mp4box/stsd.rs
index 635ac892..9a995bb2 100644
--- a/src/mp4box/stsd.rs
+++ b/src/mp4box/stsd.rs
@@ -58,10 +58,6 @@ impl Mp4Box for StsdBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/stss.rs b/src/mp4box/stss.rs
index 11b8d330..f6bed516 100644
--- a/src/mp4box/stss.rs
+++ b/src/mp4box/stss.rs
@@ -33,10 +33,6 @@ impl Mp4Box for StssBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/stsz.rs b/src/mp4box/stsz.rs
index 38855df2..738b98f4 100644
--- a/src/mp4box/stsz.rs
+++ b/src/mp4box/stsz.rs
@@ -35,10 +35,6 @@ impl Mp4Box for StszBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "sample_size={} sample_count={} sample_sizes={}",
diff --git a/src/mp4box/stts.rs b/src/mp4box/stts.rs
index 66e76e54..9eab5062 100644
--- a/src/mp4box/stts.rs
+++ b/src/mp4box/stts.rs
@@ -39,10 +39,6 @@ impl Mp4Box for SttsBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("entries={}", self.entries.len());
         Ok(s)
diff --git a/src/mp4box/tfdt.rs b/src/mp4box/tfdt.rs
index 68e55e9e..aa2d5ef9 100644
--- a/src/mp4box/tfdt.rs
+++ b/src/mp4box/tfdt.rs
@@ -36,10 +36,6 @@ impl Mp4Box for TfdtBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("base_media_decode_time={}", self.base_media_decode_time);
         Ok(s)
diff --git a/src/mp4box/tfhd.rs b/src/mp4box/tfhd.rs
index bc51684c..10b8d86b 100644
--- a/src/mp4box/tfhd.rs
+++ b/src/mp4box/tfhd.rs
@@ -57,10 +57,6 @@ impl Mp4Box for TfhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("track_id={}", self.track_id);
         Ok(s)
diff --git a/src/mp4box/tkhd.rs b/src/mp4box/tkhd.rs
index 58b0f6a3..56063b25 100644
--- a/src/mp4box/tkhd.rs
+++ b/src/mp4box/tkhd.rs
@@ -125,10 +125,6 @@ impl Mp4Box for TkhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "creation_time={} track_id={} duration={} layer={} volume={} matrix={} width={} height={}",
diff --git a/src/mp4box/traf.rs b/src/mp4box/traf.rs
index bdd5ffec..2c212903 100644
--- a/src/mp4box/traf.rs
+++ b/src/mp4box/traf.rs
@@ -35,10 +35,6 @@ impl Mp4Box for TrafBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/trak.rs b/src/mp4box/trak.rs
index e0c286a1..40b06b4f 100644
--- a/src/mp4box/trak.rs
+++ b/src/mp4box/trak.rs
@@ -43,10 +43,6 @@ impl Mp4Box for TrakBox {
         self.get_size()
     }
 
-    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> {
         let s = String::new();
         Ok(s)
diff --git a/src/mp4box/trex.rs b/src/mp4box/trex.rs
index 2a458617..8cbc6e94 100644
--- a/src/mp4box/trex.rs
+++ b/src/mp4box/trex.rs
@@ -34,10 +34,6 @@ impl Mp4Box for TrexBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "track_id={} default_sample_duration={}",
diff --git a/src/mp4box/trun.rs b/src/mp4box/trun.rs
index 793d53d0..444bf9cd 100644
--- a/src/mp4box/trun.rs
+++ b/src/mp4box/trun.rs
@@ -68,10 +68,6 @@ impl Mp4Box for TrunBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("sample_size={}", self.sample_count);
         Ok(s)
diff --git a/src/mp4box/tx3g.rs b/src/mp4box/tx3g.rs
index 7edcc34d..ef009009 100644
--- a/src/mp4box/tx3g.rs
+++ b/src/mp4box/tx3g.rs
@@ -61,10 +61,6 @@ impl Mp4Box for Tx3gBox {
         self.get_size()
     }
 
-    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> {
         let s = format!("data_reference_index={} horizontal_justification={} vertical_justification={} rgba={}{}{}{}",
             self.data_reference_index, self.horizontal_justification,
diff --git a/src/mp4box/udta.rs b/src/mp4box/udta.rs
index 3fb40b42..aedce92d 100644
--- a/src/mp4box/udta.rs
+++ b/src/mp4box/udta.rs
@@ -34,10 +34,6 @@ impl Mp4Box for UdtaBox {
         self.get_size()
     }
 
-    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> {
         Ok(String::new())
     }
diff --git a/src/mp4box/vmhd.rs b/src/mp4box/vmhd.rs
index 3eb8c9fa..e13df770 100644
--- a/src/mp4box/vmhd.rs
+++ b/src/mp4box/vmhd.rs
@@ -38,10 +38,6 @@ impl Mp4Box for VmhdBox {
         self.get_size()
     }
 
-    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> {
         let s = format!(
             "graphics_mode={} op_color={}{}{}",
diff --git a/src/mp4box/vp09.rs b/src/mp4box/vp09.rs
index 099339f7..e3e95bc5 100644
--- a/src/mp4box/vp09.rs
+++ b/src/mp4box/vp09.rs
@@ -74,10 +74,6 @@ impl Mp4Box for Vp09Box {
         0x6A
     }
 
-    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> {
         Ok(format!("{self:?}"))
     }
diff --git a/src/mp4box/vpcc.rs b/src/mp4box/vpcc.rs
index f3beaf2a..520ec29a 100644
--- a/src/mp4box/vpcc.rs
+++ b/src/mp4box/vpcc.rs
@@ -31,10 +31,6 @@ impl Mp4Box for VpccBox {
         HEADER_SIZE + HEADER_EXT_SIZE + 8
     }
 
-    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> {
         Ok(format!("{self:?}"))
     }

From 12dac2e0eeee436417d17d061cd69dd832c6aa6b Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 13:08:10 -0400
Subject: [PATCH 5/8] remove more calls to unwrap.

---
 src/error.rs       |  2 +
 src/mp4box/dinf.rs | 10 +----
 src/mp4box/emsg.rs |  8 +++-
 src/mp4box/ilst.rs | 10 +----
 src/mp4box/mdia.rs | 18 ++-------
 src/mp4box/minf.rs | 12 ++----
 src/mp4box/mod.rs  |  8 +++-
 src/mp4box/moof.rs | 11 +-----
 src/mp4box/moov.rs |  8 +---
 src/track.rs       | 93 +++++++++++++++++++++++++++++++++-------------
 10 files changed, 98 insertions(+), 82 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 11690f0c..a09b9829 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -26,4 +26,6 @@ pub enum Error {
     EntryInTrunNotFound(u32, BoxType, u32),
     #[error("{0} version {1} is not supported")]
     UnsupportedBoxVersion(BoxType, u8),
+    #[error("{0}")]
+    GenericError(String),
 }
diff --git a/src/mp4box/dinf.rs b/src/mp4box/dinf.rs
index a6943c70..af6fbc2f 100644
--- a/src/mp4box/dinf.rs
+++ b/src/mp4box/dinf.rs
@@ -64,15 +64,9 @@ impl<R: Read + Seek> ReadBox<&mut R> for DinfBox {
             current = reader.stream_position()?;
         }
 
-        if dref.is_none() {
-            return Err(Error::BoxNotFound(BoxType::DrefBox));
-        }
-
+        let dref = dref.ok_or(Error::BoxNotFound(BoxType::DrefBox))?;
         skip_bytes_to(reader, start + size)?;
-
-        Ok(DinfBox {
-            dref: dref.unwrap(),
-        })
+        Ok(DinfBox { dref })
     }
 }
 
diff --git a/src/mp4box/emsg.rs b/src/mp4box/emsg.rs
index 921dd4d8..1028ed0a 100644
--- a/src/mp4box/emsg.rs
+++ b/src/mp4box/emsg.rs
@@ -127,13 +127,17 @@ impl<W: Write> WriteBox<&mut W> for EmsgBox {
                 write_null_terminated_str(writer, &self.scheme_id_uri)?;
                 write_null_terminated_str(writer, &self.value)?;
                 writer.write_u32::<BigEndian>(self.timescale)?;
-                writer.write_u32::<BigEndian>(self.presentation_time_delta.unwrap())?;
+                writer.write_u32::<BigEndian>(self.presentation_time_delta.ok_or(
+                    crate::error::Error::InvalidData("presentation_time_delta not found"),
+                )?)?;
                 writer.write_u32::<BigEndian>(self.event_duration)?;
                 writer.write_u32::<BigEndian>(self.id)?;
             }
             1 => {
                 writer.write_u32::<BigEndian>(self.timescale)?;
-                writer.write_u64::<BigEndian>(self.presentation_time.unwrap())?;
+                writer.write_u64::<BigEndian>(self.presentation_time.ok_or(
+                    crate::error::Error::InvalidData("presentation_time not found"),
+                )?)?;
                 writer.write_u32::<BigEndian>(self.event_duration)?;
                 writer.write_u32::<BigEndian>(self.id)?;
                 write_null_terminated_str(writer, &self.scheme_id_uri)?;
diff --git a/src/mp4box/ilst.rs b/src/mp4box/ilst.rs
index 9336b902..9be03439 100644
--- a/src/mp4box/ilst.rs
+++ b/src/mp4box/ilst.rs
@@ -149,15 +149,9 @@ impl<R: Read + Seek> ReadBox<&mut R> for IlstItemBox {
             current = reader.stream_position()?;
         }
 
-        if data.is_none() {
-            return Err(Error::BoxNotFound(BoxType::DataBox));
-        }
-
+        let data = data.ok_or(Error::BoxNotFound(BoxType::DataBox))?;
         skip_bytes_to(reader, start + size)?;
-
-        Ok(IlstItemBox {
-            data: data.unwrap(),
-        })
+        Ok(IlstItemBox { data })
     }
 }
 
diff --git a/src/mp4box/mdia.rs b/src/mp4box/mdia.rs
index ea4d647b..19009168 100644
--- a/src/mp4box/mdia.rs
+++ b/src/mp4box/mdia.rs
@@ -75,23 +75,13 @@ impl<R: Read + Seek> ReadBox<&mut R> for MdiaBox {
             current = reader.stream_position()?;
         }
 
-        if mdhd.is_none() {
-            return Err(Error::BoxNotFound(BoxType::MdhdBox));
-        }
-        if hdlr.is_none() {
-            return Err(Error::BoxNotFound(BoxType::HdlrBox));
-        }
-        if minf.is_none() {
-            return Err(Error::BoxNotFound(BoxType::MinfBox));
-        }
+        let mdhd = mdhd.ok_or(Error::BoxNotFound(BoxType::MdhdBox))?;
+        let hdlr = hdlr.ok_or(Error::BoxNotFound(BoxType::HdlrBox))?;
+        let minf = minf.ok_or(Error::BoxNotFound(BoxType::MinfBox))?;
 
         skip_bytes_to(reader, start + size)?;
 
-        Ok(MdiaBox {
-            mdhd: mdhd.unwrap(),
-            hdlr: hdlr.unwrap(),
-            minf: minf.unwrap(),
-        })
+        Ok(MdiaBox { mdhd, hdlr, minf })
     }
 }
 
diff --git a/src/mp4box/minf.rs b/src/mp4box/minf.rs
index 6eb561fc..20d22a03 100644
--- a/src/mp4box/minf.rs
+++ b/src/mp4box/minf.rs
@@ -93,20 +93,16 @@ impl<R: Read + Seek> ReadBox<&mut R> for MinfBox {
             current = reader.stream_position()?;
         }
 
-        if dinf.is_none() {
-            return Err(Error::BoxNotFound(BoxType::DinfBox));
-        }
-        if stbl.is_none() {
-            return Err(Error::BoxNotFound(BoxType::StblBox));
-        }
+        let dinf = dinf.ok_or(Error::BoxNotFound(BoxType::DinfBox))?;
+        let stbl = stbl.ok_or(Error::BoxNotFound(BoxType::StblBox))?;
 
         skip_bytes_to(reader, start + size)?;
 
         Ok(MinfBox {
             vmhd,
             smhd,
-            dinf: dinf.unwrap(),
-            stbl: stbl.unwrap(),
+            dinf,
+            stbl,
         })
     }
 }
diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index 19578b17..068f11e4 100644
--- a/src/mp4box/mod.rs
+++ b/src/mp4box/mod.rs
@@ -242,11 +242,15 @@ impl BoxHeader {
         reader.read_exact(&mut buf)?;
 
         // Get size.
-        let s = buf[0..4].try_into().unwrap();
+        let s = buf[0..4]
+            .try_into()
+            .map_err(|_e| crate::error::Error::InvalidData("could not get slice"))?;
         let size = u32::from_be_bytes(s);
 
         // Get box type string.
-        let t = buf[4..8].try_into().unwrap();
+        let t = buf[4..8]
+            .try_into()
+            .map_err(|_e| crate::error::Error::InvalidData("could not get slice"))?;
         let typ = u32::from_be_bytes(t);
 
         // Get largesize if size is 1
diff --git a/src/mp4box/moof.rs b/src/mp4box/moof.rs
index e90c1f50..c4839a23 100644
--- a/src/mp4box/moof.rs
+++ b/src/mp4box/moof.rs
@@ -76,16 +76,9 @@ impl<R: Read + Seek> ReadBox<&mut R> for MoofBox {
             current = reader.stream_position()?;
         }
 
-        if mfhd.is_none() {
-            return Err(Error::BoxNotFound(BoxType::MfhdBox));
-        }
-
+        let mfhd = mfhd.ok_or(Error::BoxNotFound(BoxType::MfhdBox))?;
         skip_bytes_to(reader, start + size)?;
-
-        Ok(MoofBox {
-            mfhd: mfhd.unwrap(),
-            trafs,
-        })
+        Ok(MoofBox { mfhd, trafs })
     }
 }
 
diff --git a/src/mp4box/moov.rs b/src/mp4box/moov.rs
index 70578d97..00ef2f93 100644
--- a/src/mp4box/moov.rs
+++ b/src/mp4box/moov.rs
@@ -105,14 +105,10 @@ impl<R: Read + Seek> ReadBox<&mut R> for MoovBox {
             current = reader.stream_position()?;
         }
 
-        if mvhd.is_none() {
-            return Err(Error::BoxNotFound(BoxType::MvhdBox));
-        }
-
+        let mvhd = mvhd.ok_or(Error::BoxNotFound(BoxType::MvhdBox))?;
         skip_bytes_to(reader, start + size)?;
-
         Ok(MoovBox {
-            mvhd: mvhd.unwrap(),
+            mvhd,
             meta,
             udta,
             mvex,
diff --git a/src/track.rs b/src/track.rs
index 472ca1d5..946eba47 100644
--- a/src/track.rs
+++ b/src/track.rs
@@ -343,7 +343,10 @@ impl Mp4Track {
     }
 
     fn ctts_index(&self, sample_id: u32) -> Result<(usize, u32)> {
-        let ctts = self.trak.mdia.minf.stbl.ctts.as_ref().unwrap();
+        let ctts = self.trak.mdia.minf.stbl.ctts.as_ref().ok_or(
+            // todo: is this the correct error to return here?
+            crate::error::Error::BoxNotFound(BoxType::CttsBox),
+        )?;
         let mut sample_count: u32 = 1;
         for (i, entry) in ctts.entries.iter().enumerate() {
             let next_sample_count =
@@ -366,30 +369,36 @@ impl Mp4Track {
     }
 
     /// return `(traf_idx, sample_idx_in_trun)`
-    fn find_traf_idx_and_sample_idx(&self, sample_id: u32) -> Option<(usize, usize)> {
+    fn find_traf_idx_and_sample_idx(&self, sample_id: u32) -> Result<Option<(usize, usize)>> {
         let global_idx = sample_id - 1;
         let mut offset = 0;
         for traf_idx in 0..self.trafs.len() {
             if let Some(trun) = &self.trafs[traf_idx].trun {
                 let sample_count = trun.sample_count;
                 if sample_count > (global_idx - offset) {
-                    return Some((traf_idx, (global_idx - offset) as _));
+                    return Ok(Some((traf_idx, (global_idx - offset) as _)));
                 }
-                offset = offset
-                    .checked_add(sample_count)
-                    .expect("attempt to sum trun sample_count with overflow");
+                offset =
+                    offset
+                        .checked_add(sample_count)
+                        .ok_or(crate::error::Error::InvalidData(
+                            "attempt to sum trun sample_count with overflow",
+                        ))?;
             }
         }
-        None
+        Ok(None)
     }
 
     fn sample_size(&self, sample_id: u32) -> Result<u32> {
         if !self.trafs.is_empty() {
-            if let Some((traf_idx, sample_idx)) = self.find_traf_idx_and_sample_idx(sample_id) {
+            if let Some((traf_idx, sample_idx)) = self.find_traf_idx_and_sample_idx(sample_id)? {
                 if let Some(size) = self.trafs[traf_idx]
                     .trun
                     .as_ref()
-                    .unwrap()
+                    .ok_or(crate::error::Error::BoxInTrafNotFound(
+                        traf_idx as u32,
+                        BoxType::TrunBox,
+                    ))?
                     .sample_sizes
                     .get(sample_idx)
                 {
@@ -436,7 +445,7 @@ impl Mp4Track {
 
     fn sample_offset(&self, sample_id: u32) -> Result<u64> {
         if !self.trafs.is_empty() {
-            if let Some((traf_idx, _sample_idx)) = self.find_traf_idx_and_sample_idx(sample_id) {
+            if let Some((traf_idx, _sample_idx)) = self.find_traf_idx_and_sample_idx(sample_id)? {
                 Ok(self.trafs[traf_idx].tfhd.base_data_offset.unwrap_or(0))
             } else {
                 Err(Error::BoxInTrafNotFound(self.track_id(), BoxType::TrafBox))
@@ -445,7 +454,13 @@ impl Mp4Track {
             let stsc_index = self.stsc_index(sample_id)?;
 
             let stsc = &self.trak.mdia.minf.stbl.stsc;
-            let stsc_entry = stsc.entries.get(stsc_index).unwrap();
+            let stsc_entry =
+                stsc.entries
+                    .get(stsc_index)
+                    .ok_or(crate::error::Error::GenericError(format!(
+                        "stsc entry not found for sample_id: {}, stsc_idx: {}",
+                        sample_id, stsc_index
+                    )))?;
 
             let first_chunk = stsc_entry.first_chunk;
             let first_sample = stsc_entry.first_sample;
@@ -507,14 +522,19 @@ impl Mp4Track {
         }
     }
 
-    fn sample_rendering_offset(&self, sample_id: u32) -> i32 {
+    fn sample_rendering_offset(&self, sample_id: u32) -> Result<i32> {
         if let Some(ref ctts) = self.trak.mdia.minf.stbl.ctts {
             if let Ok((ctts_index, _)) = self.ctts_index(sample_id) {
-                let ctts_entry = ctts.entries.get(ctts_index).unwrap();
-                return ctts_entry.sample_offset;
+                let ctts_entry =
+                    ctts.entries
+                        .get(ctts_index)
+                        .ok_or(crate::error::Error::InvalidData(
+                            "ctts not found after ctts_index was returned",
+                        ))?;
+                return Ok(ctts_entry.sample_offset);
             }
         }
-        0
+        Ok(0)
     }
 
     fn is_sync_sample(&self, sample_id: u32) -> bool {
@@ -550,8 +570,8 @@ impl Mp4Track {
         reader.seek(SeekFrom::Start(sample_offset))?;
         reader.read_exact(&mut buffer)?;
 
-        let (start_time, duration) = self.sample_time(sample_id).unwrap(); // XXX
-        let rendering_offset = self.sample_rendering_offset(sample_id);
+        let (start_time, duration) = self.sample_time(sample_id)?; // XXX
+        let rendering_offset = self.sample_rendering_offset(sample_id)?;
         let is_sync = self.is_sync_sample(sample_id);
 
         Ok(Some(Mp4Sample {
@@ -780,9 +800,16 @@ impl Mp4TrackWriter {
         Ok(self.trak.tkhd.duration)
     }
 
-    fn chunk_count(&self) -> u32 {
-        let co64 = self.trak.mdia.minf.stbl.co64.as_ref().unwrap();
-        co64.entries.len() as u32
+    fn chunk_count(&self) -> Result<u32> {
+        let co64 = self
+            .trak
+            .mdia
+            .minf
+            .stbl
+            .co64
+            .as_ref()
+            .ok_or(crate::error::Error::BoxNotFound(BoxType::Co64Box))?;
+        Ok(co64.entries.len() as u32)
     }
 
     fn update_sample_to_chunk(&mut self, chunk_id: u32) {
@@ -801,9 +828,17 @@ impl Mp4TrackWriter {
         self.trak.mdia.minf.stbl.stsc.entries.push(entry);
     }
 
-    fn update_chunk_offsets(&mut self, offset: u64) {
-        let co64 = self.trak.mdia.minf.stbl.co64.as_mut().unwrap();
+    fn update_chunk_offsets(&mut self, offset: u64) -> Result<()> {
+        let co64 = self
+            .trak
+            .mdia
+            .minf
+            .stbl
+            .co64
+            .as_mut()
+            .ok_or(crate::error::Error::BoxNotFound(BoxType::Co64Box))?;
         co64.entries.push(offset);
+        Ok(())
     }
 
     fn write_chunk<W: Write + Seek>(&mut self, writer: &mut W) -> Result<()> {
@@ -814,8 +849,8 @@ impl Mp4TrackWriter {
 
         writer.write_all(&self.chunk_buffer)?;
 
-        self.update_sample_to_chunk(self.chunk_count() + 1);
-        self.update_chunk_offsets(chunk_offset);
+        self.update_sample_to_chunk(self.chunk_count()? + 1);
+        self.update_chunk_offsets(chunk_offset)?;
 
         self.chunk_buffer.clear();
         self.chunk_samples = 0;
@@ -848,7 +883,15 @@ impl Mp4TrackWriter {
             // mp4a.esds.es_desc.dec_config.max_bitrate
             // mp4a.esds.es_desc.dec_config.avg_bitrate
         }
-        if let Ok(stco) = StcoBox::try_from(self.trak.mdia.minf.stbl.co64.as_ref().unwrap()) {
+        if let Ok(stco) = StcoBox::try_from(
+            self.trak
+                .mdia
+                .minf
+                .stbl
+                .co64
+                .as_ref()
+                .ok_or(crate::error::Error::BoxNotFound(BoxType::Co64Box))?,
+        ) {
             self.trak.mdia.minf.stbl.stco = Some(stco);
             self.trak.mdia.minf.stbl.co64 = None;
         }

From f5a8be435c077609f6207a359fb088646ac67b5b Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 13:09:09 -0400
Subject: [PATCH 6/8] fix(clippy)

---
 src/mp4box/mod.rs  | 2 +-
 src/mp4box/soun.rs | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index 068f11e4..00b7d2f7 100644
--- a/src/mp4box/mod.rs
+++ b/src/mp4box/mod.rs
@@ -87,7 +87,7 @@ pub(crate) mod mp4a;
 pub(crate) mod mvex;
 pub(crate) mod mvhd;
 pub(crate) mod smhd;
-pub(crate) mod soun;
+//pub(crate) mod soun;
 pub(crate) mod stbl;
 pub(crate) mod stco;
 pub(crate) mod stsc;
diff --git a/src/mp4box/soun.rs b/src/mp4box/soun.rs
index b2ddabab..4d2ad48a 100644
--- a/src/mp4box/soun.rs
+++ b/src/mp4box/soun.rs
@@ -1,4 +1,4 @@
-use serde::Serialize;
+/*use serde::Serialize;
 
 use crate::mp4box::*;
 
@@ -25,4 +25,4 @@ impl Mp4Box for SounBox {
     fn summary(&self) -> Result<String> {
         todo!()
     }
-}
+}*/

From 0e81b1f70c2141d396cf80c131f2429181dee26f Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 15:18:48 -0400
Subject: [PATCH 7/8] chore(mp4box): remove soun module

---
 src/mp4box/mod.rs  |  4 +---
 src/mp4box/soun.rs | 28 ----------------------------
 2 files changed, 1 insertion(+), 31 deletions(-)
 delete mode 100644 src/mp4box/soun.rs

diff --git a/src/mp4box/mod.rs b/src/mp4box/mod.rs
index 00b7d2f7..3f85c3ee 100644
--- a/src/mp4box/mod.rs
+++ b/src/mp4box/mod.rs
@@ -87,7 +87,6 @@ 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;
@@ -200,8 +199,7 @@ boxtype! {
     DayBox => 0xa9646179,
     CovrBox => 0x636f7672,
     DescBox => 0x64657363,
-    WideBox => 0x77696465,
-    SounBox => 0x736F756E
+    WideBox => 0x77696465
 }
 
 pub trait Mp4Box: Sized {
diff --git a/src/mp4box/soun.rs b/src/mp4box/soun.rs
deleted file mode 100644
index 4d2ad48a..00000000
--- a/src/mp4box/soun.rs
+++ /dev/null
@@ -1,28 +0,0 @@
-/*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 summary(&self) -> Result<String> {
-        todo!()
-    }
-}*/

From 86cc3481007054393c22147d10c599633d898c7c Mon Sep 17 00:00:00 2001
From: Stuart Woodbury <stuartwoodbury@protonmail.ch>
Date: Wed, 5 Jul 2023 16:34:09 -0400
Subject: [PATCH 8/8] chore(reader): refactor read_header

---
 src/reader.rs | 37 ++++++++++++++-----------------------
 1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/src/reader.rs b/src/reader.rs
index 45c64b17..88d86bf9 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -72,33 +72,24 @@ impl<R: Read + Seek> Mp4Reader<R> {
             current = reader.stream_position()?;
         }
 
-        if ftyp.is_none() {
-            return Err(Error::BoxNotFound(BoxType::FtypBox));
-        }
-        if moov.is_none() {
-            return Err(Error::BoxNotFound(BoxType::MoovBox));
-        }
+        let ftyp = ftyp.ok_or(Error::BoxNotFound(BoxType::FtypBox))?;
+        let moov = moov.ok_or(Error::BoxNotFound(BoxType::MoovBox))?;
 
         let size = current - start;
-        let mut tracks = if let Some(ref moov) = moov {
-            if moov.traks.iter().any(|trak| trak.tkhd.track_id == 0) {
-                return Err(Error::InvalidData("illegal track id 0"));
-            }
-            moov.traks
-                .iter()
-                .map(|trak| (trak.tkhd.track_id, Mp4Track::from(trak)))
-                .collect()
-        } else {
-            HashMap::new()
-        };
+        if moov.traks.iter().any(|trak| trak.tkhd.track_id == 0) {
+            return Err(Error::InvalidData("illegal track id 0"));
+        }
+        let mut tracks: HashMap<u32, Mp4Track> = moov
+            .traks
+            .iter()
+            .map(|trak| (trak.tkhd.track_id, Mp4Track::from(trak)))
+            .collect();
 
         // Update tracks if any fragmented (moof) boxes are found.
         if !moofs.is_empty() {
             let mut default_sample_duration = 0;
-            if let Some(ref moov) = moov {
-                if let Some(ref mvex) = &moov.mvex {
-                    default_sample_duration = mvex.trex.default_sample_duration
-                }
+            if let Some(ref mvex) = &moov.mvex {
+                default_sample_duration = mvex.trex.default_sample_duration
             }
 
             for moof in moofs.iter() {
@@ -116,8 +107,8 @@ impl<R: Read + Seek> Mp4Reader<R> {
 
         Ok(Mp4Reader {
             reader,
-            ftyp: ftyp.ok_or(crate::error::Error::BoxNotFound(BoxType::FtypBox))?,
-            moov: moov.ok_or(crate::error::Error::BoxNotFound(BoxType::MoovBox))?,
+            ftyp,
+            moov,
             moofs,
             emsgs,
             size,