I have a project for school and am using premiere elements ten to edit, which I need to do since it is my personal favourite for school media projects. And i habe downloaded youtube videos with video downloader from firefox. And when i play them they are good quality on any program except when I am editing on premeire. Any help would be amazing. Thanks.
Downloaded video from YouTube does not make the best source material for Premiere Elements. This is because it has been transcoded and compressed once by the person who posted it to the site, then transcoded and compressed again by YouTube then transcoded and compressed AGAIN by the software you used to download it. Also, a lot depends on the quality and resolution of the footage posted to YouTube and the quality and format of the video your software used to download it. (There are dozens of programs that download video from YouTube and vary wildly in quality.)
You also need to consider how compatible the video format is you downloaded and which settings you used in Premiere Elements when you set up your project.
In short, there are a lot of variables here -- but the short answer is that you're just not going to get good, editable video from YouTube. And even if you do get acceptable footage, it's pretty much impossible for it to be as good as first generation video directly from a camcorder.