Rendering suddenly broken - no video, only audio

Was working perfectly a week ago.

Ubuntu Precise and Kdenlive 0.8.2.1 (melt 0.7.6).

Tried to render a new project today and only audio is rendering. Loaded an older project that rendered fine previously and the same thing is now happening.

My usual rendering format is h.264, but the same thing is happening to all other formats (.avi formats won't render at all and just crash).

Have done nothing out of the ordinary other than install xcfe desktop - would this break rendering? (same issues occurring if I switch back to Unity).

Forums:

Duel boot with Vector linux, then install kdenlive and even openshot together. Both programs run supreme in vector and as intended. Ubuntu does not play nice with these programs. Or they will tell you that "It runs fine on my machine" or "Its your hardware" I learned a long time ago not to use any video editing programs in ubuntu.

I'm having issues with Kubuntu 12.04 too - I've been using Sunab's repository, but had now reverted back to Ubuntu's default packages. I've double checked all packages are installed with the default versions, but proxys and other rendering is still broken...

I'm on Ubuntu 12.04 and also get only audio when I render to h.264.
Other formats work fine.

I get only video, when rendering to h.264. What gives?

Not sure what was wrong, but the advice from this newer thread - http://www.kdenlive.org/forum/unable-render-produces-almost-empty-file - seems to have fixed the audio only issue I was having.