So ive just done a fresh install of my computer, due to ubuntu 12.10 being too unstable. Ive installed Ubuntu 12.04 64 bit, with the unity interface. so far its been great. (also got dual monitors setup)

So i copied over the daily build of ubuntu i had been previously using, worked perfect, except that rendering finishes in around 3 seconds, the outputed video file is tiny and doesnt play, so its obvioiusly not rendered anything and just wrote an empty file.

Kdenlive installed from the PPA from here does the same thing. so its not the daily build.

I have also tried different render profiles, they all do the same thing.

Any ideas why this is not working?

This is a fresh install of Ubuntu 12.04 and the only difference really is ATI graphics card with ATI's catylist drivers installed (fglrx-legacy with downgraded x server 1.12 as 1.13 doesnt support amds legacy driver, but dont see how this should affect rendering)

I've also upgraded my ram with 2 2gb ram modules (had 1gb and 2gb before)

After some searching, i found an old post that mentioned try running it with sudo.

sure enough running the daily build i have using sudo, and its now rendering.

this is strange.

You should not have to run as superuser. I think that this may be due to your user settings, if you look in Gnomes user settings for your logon somewhere in there is a list tick boxes to allow the user to access video and audio devices, modems, administer this and that, are the audio video ones ticked? Its only a guess, I'm on Ubuntu 12.10, previously 12.04 and before that and never had to run daily builds or PPA as superuser.

After more searching this is apperently a bug, but is listed way back in 2012, something to do with opencv

usr/lib/frei0r-1/mv facedetect.so facedetect.bak fixed the problem

However i ran

sudo apt-get upgrade and there was updates to frei0r, i gues when i updated from kdenlive the ubuntu repos to sunlabs ppa it only upgraded kdenlive and not frei0r, so it might have just been an old frei0r version.

Ive just checked my freir0r directory , theres no facedetect.so so i guess the update didnt add the file back.

Yeah, again that bug never made a great deal of difference, maybe one build on one or two days but PPA updated so regularly it never made much impact unless a user was getting that build from distro repo.

There are many Ubuntu users not having to run as superuser, have you tried looking at your user logon credentials for access to certain hardware?

Did you install loads of LADSPA plugins, some of those messed up kdenlive/MLT for me, from memory those from Tom somebody or other. :-)