What you do with the data is something else again. Once you receive a file, you need to have the proper software on your machine to make use of it. File compatibility has been a large part of computer networks for many years, so lots of effort has been put into this area. Before new software is added to an existing environment, somebody usually checks to be certain that it can work with the software that's already installed. Use the composite output.
Scan convert the output and feed it into the switcher.
In virtually every case, the result was destined to be viewed or broadcast as a composite analog signal anyway. Now, however, things are really changing. The number of advanced television formats that are available is staggering. Pretty soon, it won't be possible to fall back on composite analog NTSC because the ultimate audience won't be viewing it that way. Progressive scan and interlaced video must coexist.