after rendering no picture..?
 

So I imported some Cineform avi's form last year, which strangely enough, needed to render in a new Cineform preset.
After rendering the video shows a 'x' and no picture.

Other footage doesn't need rendering and shows picture [as usual]

What am I doing wrong?

After rendering to a new Cinefrom avi and importing that file again everything is fine, [no rendering required and the video is visible] but why?

Please send a sample file to support.