format/stream: add avg_frame_rate accessors

src/format/stream/stream.rs

@@ -84,6 +84,12 @@ impl<'a> Stream<'a> {
 			Rational::from(av_stream_get_r_frame_rate(self.as_ptr()))
 		}
 	}
+
+	pub fn avg_frame_rate(&self) -> Rational {
+		unsafe {
+			Rational::from((*self.as_ptr()).avg_frame_rate)
+		}
+	}
 }
 
 impl<'a> PartialEq for Stream<'a> {

src/format/stream/stream_mut.rs

@@ -41,6 +41,12 @@ impl<'a> StreamMut<'a> {
 		}
 	}
 
+	pub fn set_avg_frame_rate<R: Into<Rational>>(&mut self, value: R) {
+		unsafe {
+			(*self.as_mut_ptr()).avg_frame_rate = value.into().into();
+		}
+	}
+
 	pub fn set_parameters<P: Into<codec::Parameters>>(&mut self, parameters: P) {
 		let parameters = parameters.into();