The Hall SC-VGA-2 Video Processor, the Atari ST and NeXTSTEP | Hacker News Reader

The Hall SC-VGA-2 Video Processor, the Atari ST and NeXTSTEP

oldvcr.blogspot.com

62 pointstodsacerdoti13 comments

I'm surprised they dismissed the OSSC [1] so easily. It's not "just" for game consoles and arcade equipment. It has a VGA port on it for a reason!

Admittedly I haven't used it for anything nearly as "esoteric" as some of the gear Cameron has I'd be surprised if he encountered any issues. Though being open source I'd suspect if he did he could simply fix them himself in the OSSC's firmware if needed!

An OSSC will happily upscale any weird resolution/framerate you feed it to something modern HDMI devices can "understand". I use an "EVGA XR1 Lite" [2] to take the OSSC's HDMI output and feed it in over UVC to my laptop with USB-C. Works flawlessly and is dirt cheap

If Cameron wants a bit more of an "all-in-one" solution, myself and other retro tech youtubers like Tech Tangents, RetroRGB and others use old Datapath RGB E1S cards [3]. This thing is basically just a DVI port glued to an FPGA. It doesn't care about "resolution" or "refresh rate" it just DMA's raw pixel data right into RAM and lets what ever application you point at it decipher it. Personally I think they're pretty awful (comparatively) to the above option. The driver is a binary blob (so it probably won't work on Cameron's POWER machine) and it crashes a lot both under Windows and Linux. Though it seems more agreeable under Windows for changing resolution and other settings via OBS

[1] https://www.retrorgb.com/ossc.html

[2] https://www.evga.com/products/product.aspx?pn=141-U1-CB20-LR

[3] https://www.datapathltd.com/datapath-products/video-capture-...

(author) Hey, thanks. I'm still sceptical about the OSSC for this application. It doesn't seem to downsample from higher refresh rates, which is specifically what I picked up the Hall converter for (at least as far as I could tell from the wiki at https://junkerhq.net/xrgb/index.php?title=OSSC_Pro ). https://stoneagegamer.com/ossc-pro-open-source-scan-converte... just says "Common PC resolutions up to 1600×1200". The cost of a OSSC Pro unit makes me hesitant to try this out. If you're sure it can do it, though, I'll get my pennies together to give it a shot.

With the OSSC, you'd have pixel perfect sampling.

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.

The OSSC can sample even 1080p input signals.

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.

I haven't played with the "Pro" model (I think that's mostly for 4K upscale?) But I use the 'regular' OSSC to work with DOS and some PPC era Xserves and it absolutely handles them without a hitch

Oooh! I wonder if I can find one of those. I'd love a way to see all of the Amiga screenmodes on a single display :)

I don't think it can scandouble - my A4000T with a Picasso RTG card uses the onboard doubler. But if the video mode is at least 60Hz, odds are this thing would probably support it.

Look into the OSSC Pro.

I've got a mono->VGA cable for my STe, and it doesn't work with all LCD monitors. I've got a 4:3 1280x1024 display that (after tweaking display settings) resolves it to a pretty clean 1280x800 with a border at the bottom, but I tried it with a couple of displays a friend has and it seemed impossible to get it quite right. The output was very similar to the nasty screenshots shown here: monitor's pixel sampling always slightly out of sync. I wonder if it's the same phenomenon.

I vaguely remember 70 Hz and 72 Hz being VGA standards, so the ST's 71.25 Hz (or whatever it actually was) could be a bit of an oddity.

(The Nextstep output doesn't look that awesome either! Hard to say whether this is the converter or whether it's like that it source thouh.)

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