For what it's worth, the attached patch to jamu.py fixed the problem for me. I suspect it's related to storage groups (I have them off for video so I can use external players). I believe this patch is safe since it only triggers for video files that are stored by absolute path, but all I can really say is it works for me.
** Patch added: "jamu.py.diff" https://bugs.launchpad.net/ubuntu/+source/mythtv/+bug/775233/+attachment/2494853/+files/jamu.py.diff -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/775233 Title: after jamu ran from cron, all clipart is empty To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mythtv/+bug/775233/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs