[pitivi: 3/14] stream: deal with python elements in find_upstream_demuxer_and_pad

[Edward Hervey <edwardrv src gnome org>]

commit 3e9f2b73bc80bd5bdf57d57f4e81a7584ce50832
Author: Alessandro Decina <alessandro d gmail com>
Date:   Mon Sep 27 17:34:57 2010 +0200

    stream: deal with python elements in find_upstream_demuxer_and_pad

 pitivi/stream.py |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/pitivi/stream.py b/pitivi/stream.py
index d28769b..96ae7eb 100644
--- a/pitivi/stream.py
+++ b/pitivi/stream.py
@@ -269,6 +269,10 @@ def find_upstream_demuxer_and_pad(pad):
             continue
 
         element_factory = element.get_factory()
+        if element_factory is None:
+            # python elements don't have a factory
+            return None, None
+
         element_klass = element_factory.get_klass()
 
         if 'Demuxer' in element_klass: