Rather than the mess (see wavy pattern on TOS background) that you have now.
I use mine with Amiga (OCS, ECS, AGA), VGA and a Wii.
OSSC Pro is costly, in good part due to cost of FPGA and other components used, but the simpler OSSC is typically under $100.
OSSC Pro is able to buffer full frames, deinterlace and have different input and output timings, whereas OSSC operates with only a couple of lines of video data, thus is less flexible, but sufficient for most uses, with excellent low latency.
I've seen reports of success with the ST, but that's a 640x400 display at most (the lower resolutions run at lower rates anyway, which the OSSC seems to handle well). But what about higher resolutions or refresh rates? The issue with the HP was resampling a 1024x768 70/75Hz signal to 60Hz.
If you need wildly different timings for the output, you'll want the Pro, which unfortunately isn't cheap.
As for "will it capture this weird mode?" general question, it will. It does have tremendous sampling flexibility. IMHO the main selling point of the OSSC.
I've been using the OSSC to upscale a 50 Hz RGB signal (SCART) to 1024x1024 (256 lines duplicated 4x). Both my HDMI capture cards happily accept that resolution with the right software.
I haven't tried the OSSC Pro, but the Retrotink 4k should probably also work fine and is really easy to use. A bit on the expensive side though...
I already wouldn't touch the retrotink simply because it isn't open hardware, but it also is not anywhere as configurable; It's meant for non-techie people who want to be abstracted from the details.
Definitely easier to use, but nowhere as flexible.
I do not find the Retrotink 4k any less configurable than the OSSC (non-pro, I haven't tried the pro). Note that the 4k is nothing like the 5X-Pro which is more plug and play.
Rather than the mess (see wavy pattern on TOS background) that you have now.
I use mine with Amiga (OCS, ECS, AGA), VGA and a Wii.
OSSC Pro is costly, in good part due to cost of FPGA and other components used, but the simpler OSSC is typically under $100.
OSSC Pro is able to buffer full frames, deinterlace and have different input and output timings, whereas OSSC operates with only a couple of lines of video data, thus is less flexible, but sufficient for most uses, with excellent low latency.