• Please review our updated Terms and Rules here

The Open Source Scan Converter and vintage computers.

N

njroadfan

Veteran Member
Joined
Jan 21, 2011
Messages
1,642
A new toy finally arrived and I have completed testing with the machines I have on hand. First off, some links about the product

Development thread: http://shmups.system11.org/viewtopic.php?f=6&t=52158
Wiki detailing the features and settings: http://junkerhq.net/xrgb/index.php?title=OSSC

I purchased my unit pre-assembled from https://www.videogameperfection.com/

Right now the product is being made in batches and you need to put yourself onto a waiting list in order to purchase, click on "Reserve your OSSC" at the site above. It is recommended that you purchase a remote and AC power supply with the unit as well since a remote is required to change all the settings. This unit requires ALOT of tweaking to deliver an optimal picture depending on your source and your TV/monitor. The output from the OSSC might not by compatible with your display device depending on the source you have connected, particularly if you are using the Line3x,Line4x, and Line5x upscaling options. The trade off is the unit costs less then the XRGB-mini (under $200US vs. over $300 for the XRGB), and since it is a simple line doubler, there is close to no video lag introduced by the upscaler. Note: Your monitor's video processor may add its own lag! Also note that the OSSC only support RGB and component (YPbPr) video. Composite and S-Video sources are not supported at all.

If you are looking for a plug-n-play solution for video upscaling that is guaranteed to work with your TV (and also has composite and S-video in), consider the Micomsoft XRGB-mini Framemeister instead. The trade off is higher price, and a slight amount of video lag introduced into your input chain.

Below are my test results with vintage computers

Amiga 4000 with Video Toaster: Works in both 60Hz and 50Hz video modes. Interlaced modes work (the OSSC does simple bob deinterlacing), but the OSSC had trouble detecting them. Usually switching to another video input and back to the input you have the Amiga connected to clears this up. Note that this may be due to my use of an official Commodore DB-23 to HD-15 adapter which contains a sync seperator. The OSSC may be better behaved if connected via the SCART RGB input or with composite sync on the VGA port.

Apple IIgs: The 640x200 video mode on this machine is notorious for tripping up video scalers. The OSSC does work with it, but its recommended that you run Line3x mode or above. The only issue I had with it was an odd shimmering that appears to be interference. I connected my Apple IIgs via the VGA input on the OSSC, which lacks a low pass filter. I have to test via the SCART socket which does have a LPF.

Both of the above machines require that you tinker with the "Advanced Timing" settings to obtain pixel perfect results.

Will it work with XX computer? It should as long as it outputs analog RGB. In addition there is a "passthru" mode that simply digitizes the video and applies no line doubling, handy for PC-VGA sources. Digital TTL RGB sources like CGA adapters and the Commodore 128 should work with an external DAC connected.

Final Verdict: A must buy for vintage computer users and console gamers, particularly if your display is compatible with Line3x and above output modes.
 
Last edited:
After much testing and some video mode math from folks on the OSSC support forum, I got the IIgs working properly on the OSSC. There still some flickering, likely due to poor shielding somewhere in the input chain, but its pixel perfect output. Here is a direct output capture from my DVI2PCIe in 640x200 SHR video mode via the OSSC.

IIgs%20OSSC%20tweaked_zpsinxd5fhp.png~original
 
njroadfan said:
After much testing and some video mode math from folks on the OSSC support forum, I got the IIgs working properly on the OSSC. There still some flickering, likely due to poor shielding somewhere in the input chain, but its pixel perfect output. Here is a direct output capture from my DVI2PCIe in 640x200 SHR video mode via the OSSC.
Click to expand...

Wow. That's a *very* nice looking display! Tempting to me, for sure.

smp
 
Seems like a nice solution... However, I think the name is rubbish.
"Open Source" seems to be such a hyped term these days. I can't stand it when people refer to anything hardware-related as "Open Source".
"Open Source" is a term that originates from the software world, and applies to source-code, hence the "source" in "Open Source".
Hardware doesn't have source-code which I can download and compile, and *poof* suddenly my OSSC appears before me.
But for some reason people invented the term "Open Source Hardware" some time ago. That really makes no sense.
"Open Hardware", yea sure... But source? As in source code? At best that's only a very small part of the total requirement to build the hardware (firmware, HDL and such). What about the other stuff? PCB designs etc?
Not to mention that there is a very significant difference in that hardware can never be truly 'free', unless you happen to have your own fab for every component you need.

So no, I don't think "Open Source" is a good term to describe hardware.
 
Scali said:
Seems like a nice solution... However, I think the name is rubbish.
"Open Source" seems to be such a hyped term these days. I can't stand it when people refer to anything hardware-related as "Open Source".
"Open Source" is a term that originates from the software world, and applies to source-code, hence the "source" in "Open Source".
Hardware doesn't have source-code which I can download and compile, and *poof* suddenly my OSSC appears before me.
But for some reason people invented the term "Open Source Hardware" some time ago. That really makes no sense.
"Open Hardware", yea sure... But source? As in source code? At best that's only a very small part of the total requirement to build the hardware (firmware, HDL and such). What about the other stuff? PCB designs etc?
Not to mention that there is a very significant difference in that hardware can never be truly 'free', unless you happen to have your own fab for every component you need.

So no, I don't think "Open Source" is a good term to describe hardware.
Click to expand...

Do you think good ol "DIY" would be better than "Open Source" for projects like this?

Technically open source software isn't 100% free as you at minimum need a compatible computer for said software. At any rate, I do get your point :D.
 
trmg said:
Do you think good ol "DIY" would be better than "Open Source" for projects like this?
Click to expand...

Well, you could use the term "Open", but "Source" seems misplaced.
Then again, I think any kind of "Open Source" should be avoided. It's an overhyped, empty term.
I find it's quite like 'vegan': people love to stress that they're vegan, just like they love to stress that something is 'open source', while completely foregoing any practical concerns, or quality for that matter.
Because, let's face facts: 99% of the open source out there is garbage written by incompetent novice programmers who just found out from their friends at college that 'open source' is what all the cool kids are into.
There's only a handful of open source projects out there that are actually decent, and even fewer are actually production-hardened. And even of those, there's a lot of things you can point out that they haven't designed or maintained quite as well as their professional, closed competitors.
So to me, 'open source' in itself isn't quite a label of quality, on the contrary. And I think many seasoned professionals would agree.

trmg said:
Technically open source software isn't 100% free as you at minimum need a compatible computer for said software.
Click to expand...

I think that's irrelevant. Open Source software doesn't make any claims whatsoever about the hardware. It just claims that the software is open source, which it is.
Open Source Hardware on the other hand... well, clearly that is about the hardware, which is why it is missing the point.
The term 'source' only applies to a small subset of the hardware. Not to mention that a lot of the parts they use aren't actually open.
 
njroadfan said:
After much testing and some video mode math from folks on the OSSC support forum, I got the IIgs working properly on the OSSC. There still some flickering, likely due to poor shielding somewhere in the input chain, but its pixel perfect output. Here is a direct output capture from my DVI2PCIe in 640x200 SHR video mode via the OSSC.

IIgs%20OSSC%20tweaked_zpsinxd5fhp.png~original
Click to expand...

Sorry to necro-bump this thread, but can you please share the settings that you settled on in order to get this picture?
 
njroadfan said:
I got the IIgs working properly on the OSSC. There still some flickering, likely due to poor shielding somewhere in the input chain, but its pixel perfect output. Here is a direct output capture from my DVI2PCIe in 640x200 SHR video mode via the OSSC.
Click to expand...

Was the OSSC necessary? I was able to get pixel-perfect results with my DVI2PCIe without using an OSSC.
 
Trixter said:
Was the OSSC necessary? I was able to get pixel-perfect results with my DVI2PCIe without using an OSSC.
Click to expand...

It wasn't, at least for the Apple IIgs. The only real difference is that I didn't have to double the pixel height after capturing as the OSSC outputs 400 lines by default. I also didn't have to fiddle with the Epiphan capture driver settings since it was capturing digitally. Its much easier to fiddle with the OSSC settings as the picture changes in real time on the Epiphan's capture preview window. I use the OSSC mainly with displays and capture cards that don't natively support 240p video.

Jibbajaba said:
Sorry to necro-bump this thread, but can you please share the settings that you settled on in order to get this picture?
Click to expand...

Here are the settings used to get 640x200 SHR mode looking correctly on the OSSC

With line2X mode the H.samplerate should be around 1042. H.active 852 or 640 if you want to crop the overscan. You need to change H.synclen and H.backporch to center the image.

With line4X mode at generic 4:3, H.samplerate needs to be doubled so around 2085. H.active 1704.

After that you will need to adjust sampling phase to get pixel perfect output.
 
Well it's open source enough in that they give you everything you need to build your own. No black boxes with tiny legs you'd need nitric acid to determine the inner workings of. Of course you have to build it though - it's hardware. The open part of open source hearkens back to the usage tobdescribe say an IBM PC, or Apple 2. The Macs, earliest ones at least, were not designated open. They didn't even want people opening them. Maybe they should have used crazy glue.

I've heard the term used by people in the media, desgnating the transparency of information sources.
 
Chuck(G) said:
Those early macs made for a small bonanza for long screwdriver manufacturers...
Click to expand...

Were more people opening Macs than other consumer electronics? Many television sets, "boom boxes," and other such things from that era were constructed thusly. I recall working on something around that time that required a #2 Phillips about ¾" longer than anything I could buy at the time. I had to modify one.

Of course anyone working with cutting edge metal cutting equipment (and anything else with servo amplifiers) already needed obscenely long screwdrivers.
 
You must log in or register to reply here.
Back
Top