If you are going to use a changer I highly reccomend looking at either an Escient or VideoRequest unit for an interface.

I have a project without one and you can read from others all about that. I just finished a project with the Escient DVDM100 and a Sony 777es. Not a kalidescape but really cool, definetely more $$, but I will not do another changer without a similiar set up.