diff --git a/wagtailvideos/models.py b/wagtailvideos/models.py
index b4fc24e..9732b3d 100644
--- a/wagtailvideos/models.py
+++ b/wagtailvideos/models.py
@@ -173,7 +173,7 @@ def video_tag(self, attrs=None):
         transcodes = self.get_current_transcodes()
         sources = []
         for transcode in transcodes:
-            sources.append("<source src='{0}' type='video/{1}' >".format(transcode.url, transcode.media_format.name))
+            sources.append("<source src='{0}' type='video/{1}' >".format(transcode.url, transcode.media_format))
 
         sources.append("<source src='{0}' type='{1}'>"
                        .format(self.url, self.content_type))
diff --git a/wagtailvideos/transcoders/ffmpeg/ffmpeg.py b/wagtailvideos/transcoders/ffmpeg/ffmpeg.py
index 4d91c7d..17e8a0f 100644
--- a/wagtailvideos/transcoders/ffmpeg/ffmpeg.py
+++ b/wagtailvideos/transcoders/ffmpeg/ffmpeg.py
@@ -128,7 +128,7 @@ def run(self):
 
         output_dir = tempfile.mkdtemp()
         transcode_name = "{0}.{1}".format(
-            video.filename(include_ext=False), media_format.name
+            video.filename(include_ext=False), media_format
         )
 
         output_file = os.path.join(output_dir, transcode_name)