jamesmeneghello

diff --git a/libs/enzyme/mp4.py b/libs/enzyme/mp4.py
index c53f30d..05c1630 100644
--- a/libs/enzyme/mp4.py
+++ b/libs/enzyme/mp4.py
@@ -347,7 +347,8 @@ class MPEG4(core.AVContainer):
                                 tracktype = 'audio'
                             else:
                                 log.debug(u'  --> %r, %r (unknown)' % mdia)
-
+                        if mdia[0] == 0: