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It’s finally here! 8th of July 2016 goes down in the history books as the day our first batch of OSSC units arrived. Since we previewed the unit back in March, there have been improvements to the hardware and the software, making this amazing unit even better than it was before. With the final hardware in our hands, we can now review it. While we can’t publish a completely unbiased review since we sell these units in our store, we’ve tried to be as objective as possible.
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 changed now 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 just 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. Luckily, the option to simply pass-through interlace content to the TV has now been added to the unit in the latest (beta) firmware and will be available soon for everyone. This means you can now choose the best available deinterlacing for the particular game you’re running.
OSSC – Line doubler, the next generation
The OSSC takes the concept of the lag free line doubler 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, as we discussed here.
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. Unlike the preview unit we previously looked at, the 3.5mm audio connector has been moved slightly, so this allows most common audio cables to be connected, without the need to specifically seek out a slimline one.
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, or hold out for the digital audio upgrade board which we’re looking to offer later in the year.
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 that need to be tweaked here. While there are some strange sounding advanced options like “H-PLL Pre-Coast”, typically these don’t need to be changed for most sources.
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 be 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 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. Every firmware update added better and better performance, resulting in some breathtaking results. Almost all the problems encountered with the earlier firmware revisions are now gone. Let’s see how our consoles performed.
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 a squashed aspect ratio any day.
At 15khz the Dreamcast was perfect too, exhibiting a wonderful, stable noise-free image without any need to perform adjustments.
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 (in our case, a SuperGrafx model with the obligatory RGB mod) produced a rock solid, beautiful RGB image with the OSSC, requiring only a manual tweak of the sync low pass filter setting. 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.
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. 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 and the Mini simply showed up all the imperfections way more than they should have done.
The small amount of jitter or wobble we experienced with the early firmware revisions has gone too, a brilliant result.
Sega Saturn – Another near flawless performance on the new hardware. The Saturn looked crisp, bright and free from picture noise. You may need to turn on the sync low pass filter to eliminate or minimise a very tiny amount of picture jitter. For comparison, the XRGB Mini has no picture wobble/jitter but significantly 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 tweaking the sync low pass filter, the image became excellent, but there was still a very 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. Furthermore, the Spectrum SCART cable we were using turned out to be unshielded, which could have been responsible for some of the issues.
Sega Megadrive – Another beautiful, noise free result. Certain models of Megadrive seem prone to picture wobble/sync instability but it must be noted these models exhibit issues on other scalers too. Again, the effect is VERY minimal on the new firmwares and much less noticeable than the picture noise both the XRGB3 and XRGB Mini add.
Those of you who like a little Sonic 2 action will be pleased to know that with a small adjustment to the H-PLL Pre-Coast and H-PLL Post-Coast values, Sonic 2 and any other 480i Megadrive/Genesis games are perfectly playable with the OSSC.
SNES/Super Famicom – The SNES/Super Famicom is certainly the system that causes the most issues with the OSSC. On most TVs and every computer monitor we’ve tested so far, the image is great, with no noise whatsoever and just the tiniest hint of jitter if you really get your nose up against the screen. Unfortunately, on some TVs the system simply does not work and it’s impossible to get a stable picture. Marqs is still investigating some workarounds for this problem and hopefully they will be fixed in a future firmware.
Commodore 64 – The C64 does not output RGB, so we’re waiting on a transcoder before we can test this one.
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. In our tests with both the Wii and Xbox the transcoding quality was exceptional, without so much as a hint of added noise. The image was also 100% stable, without the slightest hint of jitter. The quality was easily the best we’ve ever seen in a component transcoder. None of the issues of purple tinting or picture drop-out that other transcoders exhibit appeared here, even after several hours of testing.
Now that interlace pass-through is due in a upcoming firmware update, there really is little reason to bother with any other transcoder in your setup.
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. During some more extensive testing we had the OSSC routed and split to two different displays, two scalers and a capture card for testing and comparison. In this rather convoluted setup the transition delay was 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.
Line triple and other options
The open source nature of this project means that it’s constantly evolving and new, innovative features are being added all the time. Line triple is one such feature. A world first, rather than simply take in one scanline and output two, line triple mode outputs three instead. This gives a (roughly) 720p image. This is a big advantage for displays or processors where 480p scaling isn’t terribly good. When used on a DVDO video processor, for instance, line triple mode greatly reduces the ringing effect that can be seen at the edge of some upscaled pixels. Unfortunately, line triple mode isn’t compatible with all displays, but for those who can take advantage of it it’s a great little feature. You can read more about it here.
Marqs is constantly adding new features. In the latest beta firmware we have here, there’s a new line double mode for 480p sources. While this doesn’t have great compatibility, on displays where it does work it can result in a very sharp scaling of 480p content, all without any added lag of course.
In the future, there’s even the possibility of some kinds of pixel filters or shaders. A “De-dither” filter for composite style faux transparencies (e.g the waterfalls on Sonic) has already been suggested and is at least theoretically possible.
The OSSC delivers
After all the months of waiting the OSSC is finally here and boy has it been worth the wait. The unit has so many applications for gamers, cabinet builders, system integrators and designers of gaming systems and rooms from the smallest budget to the biggest, grandest project. Its instant upscaling of 240p combined with its flawless transcoding and analogue to digital conversion make it a formidable device not just for gamers but for anyone looking for an easy way to integrate older analogue equipment into their current setup. The lack of support for anything other than Component and RGB will disappoint some, but it’s likely that an add-on device that can convert s-video and composite to RGB will appear in time.
What of the XRGB Mini, is the OSSC the new king of retro upscaling? Perhaps, but it must be remembered that the OSSC takes a radically different approach to the problem than the XRGB Mini. For starters, the OSSC can’t output in 1080p natively. With enough patience and tweaking, the XRGB Mini gives a stunning sharp 1080p picture that is generally considered to be the best. The Mini also has no compatibility issues with the SNES on any consumer television that we’re aware of. On the other hand, the OSSC has a frame and a half less input lag, much less picture noise and outputs at full RGB resolution. It lacks the sophisticated deinterlacing of the XRGB Mini, but has its own blisteringly fast deinterlacer instead and is compatible with interlace games on the Megadrive. Pair the OSSC with a DVDO video processor or a TV with excellent 480p scaling and you have yourself an incredible retro gaming setup. Highly recommended!