Collects unexpected boxes during decoding

This change introduces the ability to collect and retain any
unexpected boxes encountered during the decoding process.

Previously, the decoder would simply log a warning and discard
unexpected boxes, potentially losing valuable information.
Now, these boxes are stored in a `unexpected` Vec within their
parent structures (Moov, Trak, Mdia, Minf, Stbl, etc.).

This allows for more robust handling of malformed or extended
MP4 files, as the application can now inspect and process
unexpected boxes as needed.

Author: b01o

src/atom.rs

@@ -175,6 +175,9 @@ macro_rules! nested {
                 $( let mut [<$optional:lower>] = None;)*
                 $( let mut [<$multiple:lower>] = Vec::new();)*
 
+                // aggregate unexpected boxes, if any
+                let mut unexpected = Vec::new();
+
                 while let Some(atom) = Any::decode_maybe(buf)? {
                     match atom {
                         $(Any::$required(atom) => {
@@ -195,14 +198,18 @@ macro_rules! nested {
                         Any::Unknown(kind, _) => {
                             tracing::warn!("unknown box: {:?}", kind);
                         },
-                        _ => return Err(Error::UnexpectedBox(atom.kind())),
+                        _ => {
+                            tracing::warn!("unexpected box: {:?}", atom.kind());
+                            unexpected.push(atom);
+                        }
                     }
                 }
 
                 Ok(Self {
                     $([<$required:lower>]: [<$required:lower>].ok_or(Error::MissingBox($required::KIND))? ,)*
                     $([<$optional:lower>],)*
                     $([<$multiple:lower>],)*
+                    unexpected
                 })
             }
 

src/meta/iprp.rs

@@ -8,6 +8,7 @@ use crate::*;
 pub struct Iprp {
     pub ipco: Ipco,
     pub ipma: Vec<Ipma>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Iprp {

src/meta/mod.rs

@@ -158,6 +158,7 @@ mod tests {
                     location: "".into(),
                 }],
             },
+            unexpected: vec![],
         });
         expected.push(Iloc {
             item_locations: vec![ItemLocation {
@@ -229,6 +230,7 @@ mod tests {
                     },
                 ],
             }],
+            unexpected: vec![],
         });
         expected.push(Iref {
             references: vec![Reference {

src/moof/mod.rs

@@ -6,11 +6,12 @@ pub use traf::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Moof {
     pub mfhd: Mfhd,
     pub traf: Vec<Traf>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Moof {

src/moof/traf/mod.rs

@@ -8,7 +8,7 @@ pub use trun::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Traf {
     pub tfhd: Tfhd,
@@ -21,6 +21,7 @@ pub struct Traf {
     pub saio: Vec<Saio>,
     pub meta: Option<Meta>,
     pub udta: Option<Udta>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Traf {

src/moov/mod.rs

@@ -18,6 +18,7 @@ pub struct Moov {
     pub mvex: Option<Mvex>,
     pub trak: Vec<Trak>,
     pub udta: Option<Udta>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Moov {
@@ -137,7 +138,8 @@ mod test {
                         default_sample_description_index: 1,
                         default_sample_duration: 3000,
                         ..Default::default()
-                    }]
+                    }],
+                    unexpected: vec![],
                 }),
                 trak: vec![Trak {
                     tkhd: Tkhd {
@@ -156,7 +158,8 @@ mod test {
                                 media_rate: 1,
                                 ..Default::default()
                             }]
-                        })
+                        }),
+                        unexpected: vec![],
                     }),
                     meta: None,
                     mdia: Mdia {
@@ -184,7 +187,8 @@ mod test {
                             dinf: Dinf {
                                 dref: Dref {
                                     urls: vec![Url::default()]
-                                }
+                                },
+                                unexpected: vec![],
                             },
                             stbl: Stbl {
                                 stsd: Stsd {
@@ -224,12 +228,16 @@ mod test {
                                 },
                                 stco: Some(Stco::default()),
                                 ..Default::default()
-                            }
-                        }
+                            },
+                            unexpected: vec![],
+                        },
+                        unexpected: vec![],
                     },
-                    udta: None
+                    udta: None,
+                    unexpected: vec![],
                 }],
                 udta: None,
+                unexpected: vec![],
             }
         )
     }

src/moov/mvex/mod.rs

@@ -6,11 +6,12 @@ pub use trex::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Mvex {
     pub mehd: Option<Mehd>,
     pub trex: Vec<Trex>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Mvex {

src/moov/trak/edts/mod.rs

@@ -3,10 +3,11 @@ pub use elst::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Edts {
     pub elst: Option<Elst>,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Edts {

src/moov/trak/mdia/minf/dinf/mod.rs

@@ -3,10 +3,11 @@ pub use dref::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Dinf {
     pub dref: Dref,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Dinf {

src/moov/trak/mdia/minf/mod.rs

@@ -10,13 +10,14 @@ pub use vmhd::*;
 
 use crate::*;
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Minf {
     pub vmhd: Option<Vmhd>,
     pub smhd: Option<Smhd>,
     pub dinf: Dinf,
     pub stbl: Stbl,
+    pub unexpected: Vec<Any>,
 }
 
 impl Atom for Minf {