format/stream: add set_metadata function to StreamMut

src/format/stream/stream_mut.rs

@@ -4,7 +4,7 @@ use std::ops::Deref;
 use super::Stream;
 use ffi::*;
 use format::context::common::Context;
-use {codec, Rational};
+use {codec, Dictionary, Rational};
 
 pub struct StreamMut<'a> {
     context: &'a mut Context,
@@ -56,6 +56,13 @@ impl<'a> StreamMut<'a> {
             avcodec_parameters_copy((*self.as_mut_ptr()).codecpar, parameters.as_ptr());
         }
     }
+
+    pub fn set_metadata(&mut self, metadata: Dictionary) {
+        unsafe {
+            let metadata = metadata.disown();
+            (*self.as_mut_ptr()).metadata = metadata;
+        }
+    }
 }
 
 impl<'a> Deref for StreamMut<'a> {