I shared this over at arcade-projects forums, thought folks here might be interested too.
Finally got around to digging out my NAOMI, which doesn’t currently have a cab to call home, and connected it up to the OSSC via NAOMI VGA out/OSSC AV3. I set the OSSC to my Dreamcast profile w/ line2x and allow upsample 2x, and it worked perfectly. Only a minor tweak to v. backporch needed, depending on the game. Put together a quick video of the setup and captured some attract modes and gameplay, for anyone interested:
I think the coolest thing of this test is that games that I thought were not working on my netboot/pi setup actually are….which is most of them. For all but a handful of capcom games, the screen goes dark once the game loads. What I was able to see with the OSSC, however, is that vertical refresh rate goes from around 59.94 hz (working) to 60.3hz (non-working) once the game boots. And that would result in a loss of sync, I guess? But cycling through the inputs and back to AV3 would cause the OSSC to sync again, and the refresh rate would be back at around 59.94 hz. I should clarify that this was the first time I had tested with the OSSC. I had been testing previously via the Gonbes GBS 8200 you see in the beginning of the video, and a simple 19″ computer screen with some age on it. I’m speculating that the frequency blip would also cause the gonbes to lose sync, but I had no visibility into the fact that the game was actually running, whereas I could see on the OSSC that it still was. Maybe something for others messing around with NAOMI netboot/pi to be aware of, as a potential fix for games that don’t seem to be working via netboot.