I am writing because I have been experimenting a situation with my Mac, I have been editing a video I shoot with a Sony HD Video camera, I recorded on a DVD recorder then I converted the DVD video to Quicktime movie to work in FCP. The FCP could not filter all the GREEN bkgd, in Chromakey. It takes long time when I try to move the playhead from one point to another. The color wheel keeps moving for a long time. Also a warning square hang the playback, it start in slow motion and the warning talks about dropout, etc. Please advice on how or what could be causing this. Any one that help me will be really appreciated .Thank you very much for the attention to this matter and for the help any friend could give me.