I was sent an XML from Premiere CS6. The footage was XDCam EX 1080i50. Opening the XML in Final Cut Pro 7 the sequence has the red line on top of it requiring rendering. I imported one of the clips corresponding to the XML straight into a new sequence from the hard drive, allowed the sequence to be changed to the clip settings and the clip played smoothly without requiring rendering and no red line on top of the sequence.
I compared the new sequence to the xml sequence and the settings were exactly the same, yet the one from the XML required rendering.
Secondly I looked at the name of the smooth playing clip and found the cooresponding clip in the XML sequence and put them together on the same timeline. The same clip side by side, the one from the XML had the red line for rendering on top of it the one imported from the hard drive did not. How is this possible?
FCP thinks there is motio0n settings or distort settings that are wrong. Try selecting all clips and then remove attributes Basic Motion and Distort. Bear in mind that is you have shots with reframes then these reframes will be deleted by doing this. But if all shots are @ 100% and the pixels are square then this should get rid of any render lines.