Ok, I have two Canon GL1s. They both have firewire ports. My G4 also has firewire ports. Why can't I use the G4 as a live video mixer? The software itself sounds like it would be easy to make. Especially if you have one of those ACD 22" Displays. Hell, why would you ever need to purchase a seperate product? This would be a perfect app for Macs, if it does exist. If it doesn't exist, Why not?