I saw your post on the Blackmagic forum. AJA is a well know manufacturer of A/D and D/A converters, as well as audio embedders and deembedders to do exactly what you want. Will the blackmagic Multibridge to this for you – yes it will. What about Miranda – do they make similar stuff – YES. What about Cobalt Digital – YES. What about ISIS in Grass Valley, what about Leitch. There are COUNTLESS companies that make A/D and D/A converters, and they are all good. It’s a matter of what you want to pay, and what company you want to get tech support from. It’s also a matter of what dealer you want to deal with, and what brands they carry.
With all of this said, if you think you are going to be a smartie pants by buying a few A/D and D/A converts, and save money – you are not. There is nothing more efficient than simply running the lines between the rooms. You have no idea of what you will need – SDI, composite, component, AES audio, Time Code, RS422, analog audio. Run excellent quality cable between excellent quality patch bays, and this will be your most flexible cost effective solution. However, if you are willing to spend the $$$ to make everything SDI with embedded audio, AJA makes kick ass converters, that I use on all my installations. With that said, all the other companies make good converters as well.
Bob Zelin