Why do my files size change so much when I edit in Final Cut Pro?

I have a video (wmv) file that I have online and downloaded it to my computer, the file size was on 19mb - I edited it final cut pro by just adding a 30 second intro and then exported it into quicktime and the file is now 117mb?? how can I keep them smaller?Why do my files size change so much when I edit in Final Cut Pro?
This is a tough and rather complicated situation, but I'll do my best to explain...



The movie you downloaded has already gone through a lot of compression, so it's relatively small. When you create a project in Final Cut, it has basic settings that are typically very high quality since it assumes you're working with source content from a camera or other high-quality source. So when you bring the video in, it tries to up-sample that video to match the project settings. Then when you export the new video, it's doing so based on a higher quality source (the project you created with FC).



Basically there's no editor that can work with compressed files like you have without having to resample them at some stage. One solution would be to try and export your video from Final Cut to a smaller, more compressed format - there are dozens of options when you export. But you'll be re-compressing that wmv video after it's already been compressed, so the quality of that will not turn out good and you can't uncompress a video, so you just have to deal with whatever the outcome.



Best of luck.