Note – Features of the OSSC are subject to change and improvement, this article should be considered a preview rather than a final review.
Until now, if you wanted to play retro consoles on your HDTV, you either bought some kind of XRGB or put up with a substandard picture. Sure, there were other more affordable scalers like the ArcadeForge SLG in a box, but while they were often better than connecting your consoles directly to your HDTV, they always fell way short of the picture quality you could expect from a good quality CRT. That’s all set to change with the introduction of the Open Source Scan converter (OSSC for short). Amazingly, the work of one hardware engineer named Markus Hiienkari, the OSSC is causing a huge amount of excitement within the retro gaming communities and rightly so. If you’ve been holding out for the perfect 240p upscaler, this device may turn out to be as close to that goal as is possible.
OSSC vs traditional scaler
To understand the OSSC and what it offers, let’s have a little lesson on the history of the XRGB series. By now most people are familiar with the XRGB Mini, that magic box that connects between a HDTV and your retro consoles and almost magically makes them look great again, but not everyone’s as familiar with the XRGB3 and previous models. The Mini was something of a departure from the previous XRGB scalers, being designed more like a professional video scaler, similar to the likes of which you may find in high-end home theatre set ups. This approach has a lot of advantages, the incoming image can be scaled to a variety of resolutions, deinterlacing can be done properly, the user can zoom and pan the image and so forth and so on. The predecessor to the Mini was the XRGB3. This device featured a similar, albeit less advanced scaling solution to the Mini, but also had the famous B1 mode. In B1 mode the XRGB3 lost a lot of functionality, but it was able to upscale with no input lag whatsoever. It does this through a process called line doubling. Instead of buffering a whole frame, when converting from 240p to 480p, we can simply double each incoming scanline. By doing this, we get an image that’s nicely scaled, though only to 480p. This is the process that the XRGB1 and 2 used too. However, the old Micomsoft line doublers had compatibility issues with a lot of more recent displays and predictably, offered analogue video output only.
A note about deinterlacing – The technique of line-doubling works (with a few minor tweaks) for interlace content too. Indeed, this is how many early deinterlacers worked. This mode is often called “Bob” deinterlacing, since it can make parts of the image bob up and down. In consumer televisions, this technique was quickly abandoned in favour of more advanced and better looking deinterlacing, but for gamers it has one big advantage, zero input lag. Of course, TV manufacturers don’t care about such things and you won’t find this fast deinterlacing on any consumer TVs today. OSSCs lag-free deinterlacing is fantastic for gamers. That said, for interlace games where timing is not critical, you may certainly prefer your TVs deinterlacer to the OSSC. An interlace pass-through mode, like on the Gamecube HDMI mod, would be a good addition to the hardware.
OSSC – Line doubler, the next generation
The OSSC takes the concept of the lag free linedoubler and brings it into the digital age. Given that most TVs, especially newer sets, scale 480p very well, this is all that is needed to bring retro consoles back to life on modern TVs. The additional features offered by the XRGB Mini are nice, but often not needed, and can be added to the OSSC by combining it with another scaler such as a DVDO/ABT unit.
The first impression you get of the OSSC is how small it is. Arriving in a typical plexi-glass case, like most hobby projects these days, the unit is tiny, measuring approximately 14cm by 7cm by 3cm. It’s perfectly small enough to fit in your bag if you visit friends and want to take some retro consoles. On the downside, there are inputs on each side of the unit, which, if fully populated, can make it difficult to seat neatly next to other gear. Personally, I would have preferred a rack-mountable Hi-Fi style case to fit in with the rest of my equipment, but that would inevitably have bumped the price up quite significantly. Given the open source nature of the project it’s entirely possible we’ll see other versions in different cases too, though the standard case is certainly acceptable. In terms of input and output, we get a VGA/D-Sub15 input, a SCART input and a component video input. Output wise, there’s just a DVI connector. The only real issue with the case design is that the 3.5mm audio output is just too close to the DVI port to accommodate some thicker audio connectors.
The use of DVI output rather than HDMI has been discussed extensively in other reviews and on forums. The reason for this design choice is simple, cost. Adding HDMI output requires the purchase of an HDMI integrators licence, which costs a minimum of $7,000 dollars a year, completely prohibitive for an affordable hobby project like this. HDMI is nice in that it allows you to carry audio and video over the same cable. If you need to do this with the OSSC, you can purchase a DVI and analogue audio to HDMI integrator, which effectively makes the units output fully HDMI compliant.
Since the unit was reviewed by Fudoh over on retrogaming.hazard-city.de, the remote has changed a little, since the old small remote is now no longer available from the manufacturer. The new remote and its layout is shown here (click the picture for a bigger view).
As has been mentioned in other reviews, there are no on-screen menus or displays with the OSSC. Instead, all settings are adjusted using the LCD on the front of the unit. Unlike the XRGB Mini, there aren’t dozens of settings to tweak here. Scanline overlays obviously make an appearance, with a range of settings for controlling the intensity of the overlay. Even at the lightest setting, the scanlines will significantly darken the image, so prepared to notch the screen brightness up just a touch to compensate. For some sources, you will need to adjust the sampling phase, low pass filter and sync low pass filter settings to get the best results. Contrary to Fudoh’s experiences, I found the automatic video low pass filter setting to work very well and rarely had to adjust it at all. For sources that exhibited instability, adjusting the sync low pass filter and the sampling phase was usually the best way to eventually eliminate as much instability as possible.
There’s also the option to toggle between 480p and VGA 640×480 for 480p sources, allowing you to get perfect aspect ratio on consoles like the Dreamcast, for example. As Fudoh stated in his review, this is the only known RGB/Component to HDMI transcoder that caters for this.
Performance with consoles
Since the OSSC arrived we’ve been testing every machine we could find with it. So far the results have been extremely promising, often breathtaking. Having said that, problems we encountered on many systems suggest that there’s possibly some work to do before the unit is quite ready for a full retail release. Let’s start with the systems that work well.
Dreamcast – The Dreamcast’s unusual range of signals often causes problems for those of us wanting to integrate the console into our setup. With the OSSC, you can connect the Dreamcast to the SCART input or the VGA input and use both 15khz or 31khz signals without any issues. Theoretically, connecting via SCART should give better results since then you have all the benefits of the low pass filter, though in practise there didn’t seem to be a huge difference.
At 31khz the image is perfect as expected. Checking in the 240p suite showed a perfect result with the linearity test, showing that the image was not incorrectly squashed at all. My TV manages to slightly overscan 480p content, but since only a couple of rows of pixels are lost, I’ll take that over squashed aspect ratio any day.
At 15khz the image required some manual adjustment. In order to obtain a stable image the “Sampling Phase” setting needed to be turned right down to 0. Once this was done, the image was fantastic in 480i and 240p modes. In both 15khz (after adjustment) and 31khz the image was perfectly stable and noise free, much more so than the XRGB3 and beating even the XRGB Mini. There was a tiny bit of noise in grey areas, but this seems to happen on most of my systems and could be something like powerline interference.
Nintendo 64 – Wow, just stunning. The first time I saw the N64 running through the OSSC I thought I must have accidentally switched to the HDMI mod. This really is the best I’ve ever seen the old analogue N64 look on a fixed resolution display, easily beating the XRGB3 and the Mini this time. I don’t know if this is just because my TVs somewhat dated scaling just happens to fit the N64, or the lack of noise in the image finally brings out detail that’s usually lost, but the results were great and the image was perfectly stable.
PC Engine – Well known for causing problems with the XRGB3, the PC Engine (a SuperGrafx model with the obligatory RGB mod) produced a rock solid, beautiful RGB image with the OSSC. The aspect ratio on the console seemed a little squashed, but this happens on other scalers too. Of course, on something like a DVDO Edge or the XRGB Mini you can stretch the image out a little, but that kind of functionality is not available here.
PlayStation 2 – Another completely flawless performance from the OSSC, no matter what screen mode I threw at it. 240p from the PS2 in Disgaea looked better than I’ve ever seen it, 480i and 480p modes were no problem, even sync on green works.
The systems above really showed how the OSSC shines, but it’s performance was not always flawless just yet. The following systems exhibited some minor symptoms when used with the unit.
Atari Jaguar – I’ve just had my old Jaguar console modded with a 60hz switch, which makes an appreciable difference to a number of the consoles games. When running the console in 50hz the OSSC has difficulty determining the machines refresh rate and sometimes requires a power cycle or three, or for the user to switch to another source and then back again. When you do eventually get a picture, the quality is excellent, save for a tiny amount of trembling/jitter in the middle. Curiously, switch the console to 60hz and everything becomes perfect.
Commodore Amiga CD32 with SX32 – People who know me well know that I have a huge fondness for the Amiga line of computers. The CD32 is my current Amiga set up tailored for gaming, with a 4GB compact flash hard drive. First of all it must be said that the image quality with the OSSC was breathtaking. There was less picture noise than the XRGB Mini and compared to the XRGB3 it was night and day. For years I thought my CD32 simply had bad analogue output, but it turns out that the XRGB3 simply showed up all the imperfections way more than it should have done.
Nevertheless it must be stated that the image wasn’t perfect, there was a small but noticeable amount of wobble to parts of the image (more so than with the Sinclair Spectrum) that seemed particularly pronounced at 60hz. Even so, I’d take the OSSC over the Mini or the XRGB3 in a heartbeat here, with the scanline overlay working perfectly on 288p images too, things looked truly beautiful.
Sega Saturn – Surprisingly, the Saturn (a Model 2 NTSC unit) required quite extensive tweaking before anything approaching a stable image could be achieved. After adjusting sampling phase down to 0 and changing the analogue sync LPF to 2.5mhz the image became stable, with just a very slight wobble to parts of the text if you really looked for it (so slight you’d never notice it normally). For comparison, the XRGB Mini has no picture wobble but noticeably more picture noise in certain colours.
Sinclair Spectrum +2 – My old Spectrum +2 produced a very wobbly image when connected directly to the OSSC. After running it through a sync cleaner (the old Arcade Force Sync Strike) the image quality was improved significantly. After further tweaking the image became very stable, but there was still a slight wobble that could be detected under close scrutiny. We’re really nit-picking here and overall the image was really stunning, the Spectrum having never looked so crisp on a HDTV outside of an emulator.
Finally, the following systems proved somewhat problematic in my tests, but Markus seems confident that a fix will be found.
Sega Megadrive – Disappointingly the image with the Sega Megadrive was very prone to picture wobble. The effect was much like the manual AFC setting on the XRGB3, or the sync wobble/instability some SCART switches seem to add. This happened using a clean sync and a composite video for sync cable. Extensive tweaking of settings, using sync cleaners and so on still couldn’t get the picture to behave itself. My Megadrive is an early model Japanese unit. On closer inspection/testing this console appears to have a lot of noise (though less than with the OSSC) when used with the XRGB Mini too, possibly indicating a faulty console.
SNES/Super Famicom – Results with the SNES were disappointing and I couldn’t even get a stable image on my TV, without routing the OSSC through my DVDO Edge. This is being looked into. My Super Famicom is a multi-chip Japanese console with a SuperCIC.
Transcoding performance
Of course, the OSSC is great for converting those old analogue/component video consoles into HDMI too. This was covered in detail in Fudoh’s review, so I won’t dwell on it too long here. With both the Wii and Xbox the transcoding quality was excellent, without so much as a hint of added noise. For some reason, I experienced infrequent but annoying picture black-outs with the Wii, but I haven’t had time to fully investigate the cause of this just yet.
240p to 480i transitions
The XRGB Mini fails badly on a handful of games that change between 240p and 480i while running. Resident Evil 2 on the N64 is one example of this, as the resolution changes each time you go into your inventory. Pinball Illusions on the Amiga is another, as the Amiga’s interlace modes are used when multiball is activated. Transitioning between the two resolutions takes several seconds on the XRGB Mini. During this time you are, of course, completely blind as to what’s going on in the game, which is unlikely to help your chances.
The OSSC is able to handle transitions between 240p and 480i much better, though there are some caveats. First of all, contrary to some expectations, there usually is a re-sync required whenever the resolution changes. This is because, on most systems, the refresh rate changes slightly between 240p and 480i output. The good news is that these transitions now leave you with a black screen for around one second, fast enough to be tolerable in a lot more games. The bad news is that this number can go up significantly depending on your display and your HDMI setup in general. In my tests, adding a signal splitter for instance adds at least 2 to 3 seconds. Adding a DVI to HDMI audio integrator may also add to the time. Currently, with my OSSC routed and split to two different displays, two scalers and a capture card for testing and comparison, the transition delay is a game destroying 8 seconds. If fast 240p to 480i transitions are important to you, you need to factor this in when planning on how to setup your OSSC. If you really need to split the output between two devices, then unless you need both active at once you could use an entirely passive DVI switch that’s guaranteed not to need a re-sync.
Conclusions so far
Disappointingly for the moment I haven’t found the OSSC to be quite as good as was promised in Fudohs review. The image stability has not been incredible on a number of sources and I certainly wouldn’t call it a “virtuous child” just yet. Nevertheless, even on most of the systems that caused me problems, the results were as good and often better than what can be achieved with the XRGB scalers. The XRGB Mini may have the edge in terms of image sharpness when running at 1080p output, but the OSSC has less picture noise and less input lag. Naturally, the XRGB Mini easily has the edge with picture quality when viewing 480i content, but even here you might prefer the OSSC if reducing input lag is your top priority.
Regarding the issues I have encountered with the unit, I am of course reporting as many details as possible back to Markus, to make sure that you can all enjoy a trouble free OSSC when it finally releases to the wider public later this year. Even with the niggles, this is clearly an incredible product and with a little more time in development there’s no reason why these problems can’t be overcome.
Next time
In the next article I’ll take a look at the new, never before seen line-triple feature and also discuss chaining the OSSC through other scalers to add new features.
Ah yes de-sync, my bad =P thanks for the quick responses. Has an rgb modded snes mini been tried? Probably wouldn’t be any different but who knows
The desynch between 240p and 480i
Oh, de-sync, depends on the converter, usually an extra second but I’ve only tested one and it wasn’t any good anyway.
Sounds like an issue for instance certain Atari games can have a few extra scanlines randomly inserted if the CPU takes too long to calculate data between scanlines. For instance most games are programmed with 262 scanlines, but suppose a frame here and there exceeds the overscan limit and you may have for instance a momentary jump for one frame that has say 267 scanlines. Some games use kernels that run a few extra scanlines for this reason, to prevent CRT judders altogether. This creates odd framerates like say 57 or 58 Hz, still within tolerance of most CRTs.
Many old CRTs can still sync such ill formed signal though the screen may have momentary judder if the scan rate is not perfectly consistent, but for HDTVs being fed composite or RF, the processor may fail and the screen could black out a whole two seconds or more, leading to death. Old hardware like Atari cannot natively output RGB but only modded for composite or Svideo, hence why this thing is moot if it can’t accept vintage signals.
There is no real option for a lag free display regarding consoles that output non-standard scanline counts or frame rates, as engineers factored in component drift when designing tube sets, old analog hardware can accept a signal that is off tolerance by as much as ten percent or more, the tolerance for timings with digital displays is much tighter, often less than one percent, with more recent sets utilizing single combined analog composite / component input (where you connect the yellow cable to the green) much less fault tolerant to analog signals compared to the first generation of flat panel sets, so it is a crap shoot if off spec signals will sync to a given display. In such circumstance, an input buffer may be required, but this creates lag.
Many newer HDTV sets cannot display a non-interlaced 240p signal at all over their single integrated composite/component connection, even affecting consoles as recent as the Nintendo Wii released in 2006, which used such 240p mode to display virtual console titles. No solution is perfect, which is why I think collectors of vintage game consoles or computers should hang on to those CRT sets.
There’s RGB mods for most Atari systems now, is there not? There’s certainly one for the 2600. So far the only thing causing issues is the SNES, and lots of arcade hardware has been tested too.
Hi I have a few questions how bad is the desynch if the only thing you have in between the ossc and your tv is the dvi+audio to hdmi integrator? Also when you mention the ps2 does this include ps1 games? 1 more question has any testing been done with the nes? Thanks for your time.
desynch? PS1 games work fine. 288p (PAL) PS1 games had issues on one TV we tested but that was on an earlier firmware (final review is coming soon). RGB modded NES has been tested by other folks and works fine.
I’m itching to get a good picture with my Saturn, at least one better than what I’m getting with my cheap upscaler. What cable did you use? I have a model 1 NTSC Saturn, and I’m using a SCART cable with sync on luma which I bought on eBay.
Sync on luma is ideal with OSSC, that will work great, you will not be disappointed.
Is the OSSC not transcoding the Wii’s component YUV to RGB? or does it pass through YUV and still show signs of desynch? Apologise for the inane questions.
I’m wondering if it’s only PAL Wii’s that have this issue.
It transcodes the Wii perfectly in my tests, no de-sync.
So the Wii blackout/desynch issue mentioned in the ‘transcoding performance’ paragraph have stopped? How did you fix it?
They only really happened when using an external transcoder (Wii->Transcoder->OSSC). No problems in the latest firmware after several hours of gameplay.
Ahh I see, thanks BuckoA51! I shall be looking into getting the OSSC. Appreciate your time answering my questions, thank you.
Would love to know if you figure out why the Wii desynchs when transcoded. Seems to happen with the GBS 8200 and other VGA options.
Yes, it’s certainly not limited to the OSSC, but since the OSSC has component input too, a transcoder isn’t really necessary.
Great Preview!
Thank you very much. i hope they will come in stock as final version soon.
Would the OSSC be a recommended scaler for use with retro consoles on a PC LCD monitor (DellU2412M), or would it be better suited for use with Plasma/LCD TVs?
It is ideal for use with monitors. As long as they have manual aspect ratio controls you will be fine.
Sounds great; is there any ETA on the initial release batch, as well as a price (sorry if this is listed elsewhere)?
Hoping to keep the price under £150 but can’t promise anything yet.
Any idea how much cheaper the DIY kit will be compared to the pre-built models?
Is there any detail on what horizontal sampling rates the OSSC will support? I often use an Atari ST at “ST medium” resolution – and that puts out 640 horizontal pixels.
So far, I’ve never been able to find a device that samples that many pixels horizontally – hoping the OSSC could help!!
It supports the X68000 at medium res, but I don’t think Atari ST has been tested yet
Great! What resolution is X68000 medium res?
For an example of what I mean, see the following:
http://www.jamesfmackenzie.com/img/posts/atari_st_ultrasatan_ramdisk.png
The capture is missing columns due to horizontal undersampling – and that’s what I’m looking to avoid (hopefully) with the OSSC 🙂
Good WIP review, one might’ve expected a potential conflict of interest if there is a commercial connection for VGP with the OSSC in the pipeline but that isn’t the case. Having read Fudoh’s review, I though getting one (and the funds together first!) would have been a slam dunk but I may reserve judgement until I’ve seen more feedback.
Yes naturally there’s a conflict of interest as we’re going to be distributing them, but I always try to be as impartial as possible. I am really confident that all the serious bugs will be worked out, really the only two major issues were my Megadrive (which might be faulty anyway) and SNES. It’s important to remember that even with some of the machines where I had minor issues, the picture was still amazingly good, better often than the Mini and miles ahead of plugging directly to your HDTV.
This sounds very promising. I’m very pleased that it handles the N64 well. Hopefully it will give the XRGB some competition. I’ll definetly keep an eye out for this.
@Stardust4ever, Apparently it doesn’t have inputs for composite or s-video. It’s RGB scart, VGA and component. Maybe there is a chance it will support composite/s-video through the scart input w/adapter, I don’t know.
New firmware is in development to fix the SNES as we speak. S-Video adapters/converters are fully supported as long as they work with your retro hardware in the first place (unlike the Lindy converter I recently tested).
Of course, getting your console modded for RGB will give much better results.
Hi. Does this thing support Svideo and Composite? Most of my consoles are unmodified and I live in NTSC land where virtually no vintage or modern displays support RGB format, and many consoles such as NES cannot natively output anything higher than composite. And I do not own RGB or SCART cables for any of my 16-bit consoles SNES/Genesis/Turbografx. Also some Atari games use weird scanline counts as not every game displays 262 scanlines every frame. How would this thing handle games that output non-standard scanline counts on an A/V modded Atari?
Only RGB and component (ypbpr) is supported. I tested a S-Video to RGB transcoder recently but found it lacking when used with retro consoles.
Non-standard scanline counts are supported just fine, theoretically some TVs might choke on them but we’ve not had any reports of problems just yet.
Great Article. I’d love to know what cables you were using for each console and if the consoles were stock or had RGB mods etc…