Oh, thanks a lot, @marqs!
Now you mention, some people at Shmups are saying that the proper way in order to make this work is:
Y — Pins 17 and 20 (those used for composite video)
Pb — Pins 5 and 7 (those used for blue in a RGB signal)
Pr — Pins 13 and 15 (those used for red in a RGB signal)
Audio — Pins 2 (R), 6 (L) and 4 (ground)
Y is being routed to composite video pins instead of green ones because of Gscartsw. It detects the source at pin 20, so if there’s nothing there, it won’t detect it as a valid source and will ignore it (unless it’s in port 8).
The thing is, would the OSSC be able to handle a YPbPr signal using that setup? In other words, Y signal through pin 20 would be accepted by OSSC?