diff --git a/src/format/chapter/chapter.rs b/src/format/chapter/chapter.rs
index bdf5c9a..d5f7d56 100644
--- a/src/format/chapter/chapter.rs
+++ b/src/format/chapter/chapter.rs
@@ -22,7 +22,7 @@ impl<'a> Chapter<'a> {
 		self.index
 	}
 
-	pub fn id(&self) -> i32 {
+	pub fn id(&self) -> i64 {
 		unsafe { (*self.as_ptr()).id }
 	}
 
diff --git a/src/format/chapter/chapter_mut.rs b/src/format/chapter/chapter_mut.rs
index a055baa..ce28920 100644
--- a/src/format/chapter/chapter_mut.rs
+++ b/src/format/chapter/chapter_mut.rs
@@ -28,7 +28,7 @@ impl<'a> ChapterMut<'a> {
 }
 
 impl<'a> ChapterMut<'a> {
-	pub fn set_id(&mut self, value: i32) {
+	pub fn set_id(&mut self, value: i64) {
 		unsafe {
 			(*self.as_mut_ptr()).id = value;
 		}
diff --git a/src/format/context/output.rs b/src/format/context/output.rs
index cab9007..4b90cd4 100644
--- a/src/format/context/output.rs
+++ b/src/format/context/output.rs
@@ -110,7 +110,7 @@ impl Output {
 
 	pub fn add_chapter<R: Into<Rational>, S: AsRef<str>>(
 		&mut self,
-		id: i32,
+		id: i64,
 		time_base: R,
 		start: i64,
 		end: i64,