[Charles M Clemmons] “I thought the EX-1 could do a down conversion to SD internally and output the stream through the HD-SDI port. If so, why do I need down conversion software?”
You’re correct but you will need an SDI input card that can handle Standard Def 4:2:2 10 bit uncompressed. Maybe you already have input card and hard drive RAID. If so you could be set. Your renders will be painfully slow on a G4 though.
If you don’t have the SDI input card and RAID, you’re going to have a challenge finding a card (used?) to work on a G4. Money spent on buying gear for that system could be better spent on a new Mac, which would not need SDI to work with EX media coming from the SxS cards.
If you’re short on cash you could get an Intel iMac and external hard drives. I’m not sure what you’re budget is but if you have to buy anything for the G4 it may not be worth it unless you can find stuff cheap/used reliable.