I've been trying to perfect my PS2 setup for years now, but there's been one modern upscaler symptom haunting my favorite 2000s outings. While Sony's iconic sequel system looks perfectly fine on an old CRT TV, most of the console's releases rely on interlaced graphics that don't play nice with new screens. The result is jittery visuals that just look plain weird compared to 20 years ago, and solutions used to be far too pricey.
For a while now, I've had an OSSC at the heart of my retro console setup. FYI, that stands for Open Source Scan Converter, and I fully believe it's one of the top upscalers out there that comes with minimal caveats, and that's in part because it's a "line doubler" that multiplies horizontal pixel rows to ramp up resolutions.
That approach introduces practically no lag since it's processing visuals line by line, not unlike a CRT. Unfortunately, my relationship with the OSSC has its demons, as its Bob deinterlacing techniques fail to solve my flickery woes. The good news is that I've found a side upscaler that is specifically great for PS2 games, even if I won't be leaving the OSSC for it.
The other upscaler in my current affair is none other than the GBS Control (GBS-C for short), an open-source HDMI converter that started life as a DIY kit. It's effectively another doohickey that will allow you to connect retro consoles to modern TVs or monitors, and it boasts specific abilities that give it an edge when dealing with pesky interlaced graphics.
Interlacing is a tricksy workaround that's been used since the dawn of television sets, and it was originally developed to combat broadcast bandwidth. The technique essentially splits a frame into odd and even fields, then displays both rapidly on screen.
If you caught my deep dive on retro console scanlines, the same idea of lines appearing on screen so fast that your eye sees a completed frame applies, but rather than drawing each horizontal row progressively, interlacing will technically scan odd fields then even to make a perceivable full frame.
I should be clear that some PS2 games are compatible with progressive scan, but there are reasons why the console didn't default to 480p. The biggest is that most consumer CRT TVs in the early 2000s tapped out at 240p or 480i (576i in PAL regions like the UK and Australia), so sticking with interlaced visuals helped avoid compatibility issues. It also helped save on memory, which in turn enabled developers to work with enhanced textures and high-detail assets.
CRT TVs weren't immune to the intrinsic flicker on interlaced graphics, but it was less notable on a tube screen. That's largely thanks to the way phosphors gradually fade on screen, which helped soften the rapid interlacing of horizontal rows in conjunction with the display's shadow mask/apperture grille layer and pixel bleeding. If you take those same visuals and let deinterlacing convert them into solid frames, though, the jitter is extremely visible.
The main issue with standard deinterlacing techniques today is that it doesn't remedy the previous masked symptoms. While upscalers like the OSSC run circles around native TV solutions by eliminating lag, blurriness, and ghosting tied to using algorithms that weave horizontal lines together, "bob" deinterlacing emphasises the way interlacing inherently works.
To actually make a single frame, Bob takes even horizontal pixels and uses them to fill the odd interlaced lines and vice versa. That results in a pixel shift effect with every frame that switches pixel positions, leading to a repeated bobbing effect tied to the respective refresh rate. Simply put, PS2 games running at 60Hz will switch back and forth from odd and even rows 60 times a second, and that's the flicker you'll see on things like text and background textures.
Enter motion-adaptive deinterlacing, a technique that can actively detect if pixels are changing. It will still use the old weave approach with odd and even lines with no movement, while applying Bob algorithms to anything with movement. It's a "best of both worlds" solution that ditches the jitter while embracing the sharpness, low latency, and smoothness of Bob for when fast-paced movement is most likely to cause artifacts.
Here lies the GBS-C's specific PS2 superpower, as unlike the OSSC, it can apply motion-adaptive techniques to interlaced signals. Keep in mind I've been using the latter line doubler with gaming monitors and TVs for years now, so I'm well used to the flicker of Bob deinterlacing, especially when static menus and background textures are present. Therefore, when I clapped my eyes on the GBS-C's algorithms in action, I was pretty blown away.
I had almost gotten used to the janky jitter when playing some of my go-to PS2 romps, and I'll admit that the symptoms are sometimes subtle. For instance, in Silent Hill 2, the chaotic jiggle largely applies to background elements, like brick wall textures and static objects that calm down when James is running around. Seeing the lines on the pavement or building masonry shake around does hamper efforts to soak in the survival horror's eerie atmosphere, though, and it's easy to spot the difference with motion adaptive interlacing applied.
Having access to motion adaptive upscaling is absolutely a sole reason to grab a GBS-C, especially if your eyeballs have already wrestled with more aggressive PS2 examples like Dead or Alive 2. However, it also happens to be an impressive upscaler in its own right, offering up a wide array of settings you can control via built-in screen or a more expansive Wi-Fi menu.
The latter was a bit of a pain to get up and running, as you have to use the GBS-C as a hotspot then point it towards your home connection. Once you've got that sorted, however, you'll have access to vital settings like motion adaptive upscaling, resolution presets up to 1080p, and plenty of picture control dials. There's even a pretty in-depth dev mode that provides access to even more bells and whistles if you're really nerdy about retro console outputs.
At the same time, if my time using the GBS-C has taught me anything so far, it's that it lacks the same visual punch as the OSSC. Line doubling provides far sharper results than a "traditional" frame buffer device, as multiplying raw pixel rows simply looks better than the softer Bilinear Scaling used by the GBS-C.
I'm planning to experiment with using both the OSSC and GBS-C in conjunction, as it could be the perfect solution for my PS2 setup specifically. I'm wary that picking up two upscalers isn't remotely cost-effective, though, so if you want sharp line doubling and motion adaptive deinterlacing, it might be worth looking at the pricier OSSC Pro.
What I will say is that the results provided by all these upscalers will fall short compared to the RetroTINK-5X Pro or RetroTINK-4K. Those are two enthusiast-grade options with FPGA chips that will run rings around the GBS-C's motion adaptive upscaling with zero lag and ridiculously sharp visuals. The catch is that they cost between $300 and $750, which will absolutely be out of bounds for a lot of retro enjoyers.
For those of you on a budget, I'd say the GBS-C will provide you with a superior PS2 experience compared to using your TV's native abilities or a cheap upscaler. Just keep in mind that, just like the base OSSC, this gadget exclusively deals in RGB signals via SCART, component, or VGA, so you'll need to use the right cables or convert composite-only consoles like the NES.
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