Comment 1 for bug 1265223

It seems to be a problem between MLT (i.e melt) and Libav.
You should use/try FFmpeg. For that, follow this FAQ 's:
http://openshotusers.com/forum/viewtopic.php?f=12&t=1261
https://answers.launchpad.net/openshot/+faq/1040
Normally, your issue should be resolved.