I'm working with FCP7 on a MacBook Pro (2.4 Ghz and 4GB RAM). The footage I am editing is shot with 5D and 7D. I am running the footage from a USB hard drive. After dragging and dropping the footage to the three video tracks, I get a red bar the fourth track. I changed the codec and some sittings in the timeline, but didnt succeed to solve the problem. I will appreciate your help.
First - FCP is not designed or optimised for editing in H.264. You should transcode the footage to ProRes. You can get a free plugin from Canon that allows you to import and transcode, or spend $50 on Magic Bullet's Grinder if you prefer to edit while you import.
Second - Never edit from a USB hard drive - they do not transfer data in a way that is friendly for video, and you will never get smooth playback. Invest in a firewire drive - you will need it when you go to ProRes anyway, so get a FW800 drive if you have that port on your laptop.
I have no idea how your laptop could even play 3 streams of H.264 - To get a red bar on the fourth is not suprising.
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