I'm just upgraded to Ubuntu 12.1 - (latest verion) and installed Kdenlive 0.9.4 from the sofware center. The render options are all crossed out with a big X. I looked around various threads and found I needed to install libavcodec-extra-53. I did this but it didn't resolve the problem. I had previously installed it from the terminal following the instructions on this link
and using the alternate Sunab repository. That didn't work either. I don't know how to check if I have the right version of MLT installed, but it should be MLT 0.8.8.
Do I have to specify file paths in Kdenlive to locate the correct codecs or something. Any help would be appreciated.