I did some testing and the HDMI splitter didn't work, but the generic SCART to HDMI scaler did in 3x and 4x modes! It doesn't look bad either...WAY better then letting that scaler do the work. Here's SNES directly into the scaler via 720p on the left and SNES through the OSSC x3 into the scaler via HDMI on the right...it's not good enough for video comparisons, but for just streaming, it seems fine:
I tried getting video footage in OBS, but it looks really bad. I'm assuming it's my settings, so I'll try again in a few days using Amarec or something else.
I noticed that my Neo Geo AES wouldn't work through the OSSC at all. The signal isn't even recognized on the front panel, even when messign with the filter options. Was there ever a fix for this?
Also, for S-Video to RGB: What about the Extron DVS304? Is there a way to turn the scaling off and just use it as a signal converter?
Nope. The DVS 304 tries to deinterlace 240p. Also, it has a fixed processing chain. I think that one had about two or three frames of lag. I didn't spend long with the unit, but I quickly decided I didn't like it.
edit: Fudoh probably knows all the specifics. I think he still has one.
Using a video processor before the OSSC will add lag and reduce the OSSC to the role of scan line generator.
If you plan to use a video processor, you would be better off using a DVDO vp30 w/ABT102 card, DVDO vp50 (with the frame rate unlocked), a DVDO vp50pro, a DVDO Edge/Duo, or a Silicon Optix IA-100. The downside is you'll be outputting 480p. I can confirm that all of those processors output decent 240p scaled to 480p.
Another option: You could also use a DVDO HD+. I hear it can output 240p as a custom resolution. That would let you use the OSSC line multiplier, but the HD+ will add lag. Honestly, it would cheaper, faster, and easier to just pick up an old XRGB box. The XRGB boxes can output 240p to the OSSC. I don't have an HD+ and I haven't used one. So, I don't know how well or how fast it works.