diff -r 54505b8bad88 -r 179f9381965b src/pyams_media/zmi/templates/video-thumbnail.pt
--- a/src/pyams_media/zmi/templates/video-thumbnail.pt	Fri Dec 04 16:33:41 2015 +0100
+++ b/src/pyams_media/zmi/templates/video-thumbnail.pt	Fri Dec 04 16:34:30 2015 +0100
@@ -19,7 +19,7 @@
 					tal:condition="video_type"
 					tal:attributes="type video_type;
 									src extension:absolute_url(conversion);
-									media 'all and (max-width: {0[0]}px)'.format(media_width) if media_width else None;" />
+									media 'all and (max-width: {0}px)'.format(media_width) if media_width else None;" />
 		</tal:loop>
 	</video>
 </div>