My previous two posts about combining files (particularly including screencasts) from different sources in Final Cut Express continue to get quite a lot of traffic, so I'm posting another tip today.
As previously covered, for best results you want to make sure that the project settings (frame rate, pixel count, aspect ratio) are applied to the FCE project at the start, and also apply to all incoming files and (usually) exported movies.
But what if you've found that incoming content is in the wrong format? And you don't have the chance to re-shoot? Even if aspect ratio and frame rate is correct, the wrong pixel count can trash the video. I've come across a slap-your-forehead solution to amending incoming footage to the right format.
The solution is to do a screencast of the problematic footage! Simply set Snapz Pro X (or whatever screen capture tool you're using) to the same settings as your project, and play the problematic file in the background. If you've used Snapz Pro X to capture your initial file, it'll be pixel perfect and it doesn't matter whether the pixels and frames line up. If it's video footage, you'll need to worry about the sound - and you might need to import the old and new footage into FCE, deleting just the old video track and doing some lining up. To avoid this I'd suggest you set the project settings at the same settings as the video footage (the easy setup settings will probably allow this), and then just worry about screencast / other footage.
Hope that helps someone out there!