Further to this, S/PDIF over RCA/coax is supposed to use 0.5V - 1.0V signal levels, so the voltage divider should be easy enough to size up -- just not sure of the current draw requirements for S/PDIF, and thus the magnitude of restance to use. Say, 3kOhm and 1kOhm for a divide-by-4 ? Or a similar ratio with smaller resistors?

And I imagine that pretty much any capacitor in the pico-farad range would probably be fine for that component (?).