diff --git a/src/format/context/destructor.rs b/src/format/context/destructor.rs
index 42b41c3..e5c67fc 100644
--- a/src/format/context/destructor.rs
+++ b/src/format/context/destructor.rs
@@ -23,7 +23,13 @@ impl Drop for Destructor {
 			match self.mode {
 				Mode::Input => avformat_close_input(&mut self.ptr),
 				Mode::Output => {
-					if (*self.ptr).flags & AVFMT_NOFILE != 0 && !(*(*self.ptr).pb).av_class.is_null() {
+					if (*self.ptr).flags & AVFMT_NOFILE != 0
+						&& (*self.ptr)
+							.pb
+							.as_ref()
+							.map(|pb| !(*pb).av_class.is_null())
+							.unwrap_or(false)
+					{
 						avio_close((*self.ptr).pb);
 					}
 
diff --git a/src/format/format/input.rs b/src/format/format/input.rs
index 318b2ec..836ff78 100644
--- a/src/format/format/input.rs
+++ b/src/format/format/input.rs
@@ -7,8 +7,8 @@ pub struct Input {
 	ptr: *mut AVInputFormat,
 }
 
-unsafe impl Send for Input { }
-unsafe impl Sync for Input { }
+unsafe impl Send for Input {}
+unsafe impl Sync for Input {}
 
 impl Input {
 	pub unsafe fn wrap(ptr: *mut AVInputFormat) -> Self {
diff --git a/src/format/format/output.rs b/src/format/format/output.rs
index 56e3fda..2ff177e 100644
--- a/src/format/format/output.rs
+++ b/src/format/format/output.rs
@@ -13,8 +13,8 @@ pub struct Output {
 	ptr: *mut AVOutputFormat,
 }
 
-unsafe impl Send for Output { }
-unsafe impl Sync for Output { }
+unsafe impl Send for Output {}
+unsafe impl Sync for Output {}
 
 impl Output {
 	pub unsafe fn wrap(ptr: *mut AVOutputFormat) -> Self {