Scanlines on an HDTV

Scanlines. If you hear someone talking about scanlines when discussing video games, you know they’re a dork. I talk about scanlines a lot. Mostly with @damienmcferran and @michaelheald.

What’s the deal then? Well, when we played video games on CRT televisions, there would be faint horizontal lines between the rows of pixels. Kinda didn’t notice back in the day, but when you play an old Mega Drive through a modern HDTV, you will instantly see something is missing.

Modern TVs have built in picture scalers, so a 320×240 picture gets blown up to fit your gloriously large display. You’ll notice the pixels look big and slightly smudgy, edges bleed and the picture just looks a little… smoothed. All arcade games used to have scanlines. I swear a scanline generator/emphasiser was built into the Hanatrex monitors! Adding scanlines makes an arcade game feel even more authentic. I still play all my retro games on a 14″ Sony CRT portable TV because of this effect.

However, all is not lost. If you only have a HD TV, and let’s be honest, very soon this is all people will have, then there is help at hand. A fairly clever German called Jochum over at has been making bits of circuitry that will allow you to hook up your old SCART devices to a HD TV and get those beautiful old scanlines back.

It started off with the SLG3000, which took a VGA input, added the scanlines (adjustable too, so you could have them heavy or light) to a VGA output. This looks utterly ace on a Dreamcast with an old Dell 3:4 ratio PC monitor.

But what about consoles that don’t output VGA? Next up came a Sync Strike that basically takes an RGB SCART signal and convert it to a CSYNC composite signal, thus enabling retro gear to run on new teles. However, this does depend on what resolutions your HD TV accepts. My Samsung won’t take anything below a 640×480 resolution, which made me panic at first as things weren’t working!

So… we need another bit of circuitry. A video scaler. Video scalers have been available in Japan and to video enthusiasts for a while, but clock in at around £300. Devices like the XRGB 2 Plus cost the earth but produce great results. Recently, there’s been a growing market for cheap scaler boards from Hong Kong. They feature a multitude of inputs, some basic onscreen displays to adjust settings (including language!) and geometry, but are bare. Jochum started casing them in the same clear acrylic plastic housing that his SLG3000 and Sync Strike come in, and selling them on.

Ultimately, we have three separate doohickeys, two VGA leads and a 5v power supply to get scanlines.

Then Jochum released an SLG SCART box. This simply takes a SCART input, adds scanlines and spits out SCART. Much simpler, one box and a 5v power supply required.

Why would you go through the rigmarole of the first solution if you can do it in one box. Well, the one box came after all the other bits!

But is there more to it than that? Yes, take a look…


Plain jane. Multi-Mega RGB SCART > Samsung 38″ HD TV. Smudgy image. Lego block sized pixels and varying colours across areas of the same colour. What you don’t see from the stills is the way the image “wiggles”. Will try and get video at a later date.


SCART – Sync Strike – Scaler – VGA input

Here you can see Thunder Force III played on a Multi-Mega via RGB SCART Sync Strike > VGA/CGA Scaler > VGA input. The picture is clearer than using the HD TVs scaler. But still you can see the pixels look chunky and the colours tend to smudge into each other. In the last picture, the white edges still loose their sharpness a bit, but generally this £50 scaler is better than the built in TV scaler.



Getting better. Multi-Mega RGB SCART > SLG SCART > TV SCART input. The scanlines are quite visible on the Mega Drive, because the image has the scanlines applied to the 320×240 image, then the HD TV is scaling the picture up. However, the introduction of scanlines helps add definition to edges, clean up large areas of colour and add that retro feel. On something like a Saturn hi-res game or Dreamcast, the scanlines should look thinner as they’re applied to a higher res image, then scaled.


SCART – Sync Strike – Scaler – SLG3000 – VGA

Here we have Thunder Force III running through the Sync Strike > VGA/CGA Scaler > SLG3000. The scanlines are thinner, as they applied to the image after it’s scaled up to 640×480, as opposed to applied to the image then letting the TV do the scaling. A lot less distortion, you don’t see much “wiggling” while playing, and the picture just seems so much cleaner… and arcade like!

There are plenty of videos on YouTube about using this set up, and lengthy discussions of building your own Sync Strike on a scaler board over on the shmups forums. The SLG SCART is a great, quick and dirty way to add scanlines to your retro games. If you go the whole hog, you get a lot more control and a better output from the combination of Sync/Scaler/SLG. This can also be used to a range of inputs, including Component and CGA, and can connect to a stand alone PC monitor too.

Which ever you chose, it really does help recreate that retro feel on modern TVs.

  • Paul

    I use a megadrive – scart lead I picked up on ebay, it doesn’t solve the issue to the level the above options do, but it certainly looks tidier!

  • Segasocks

    Great article on an interesting subject.
    I have tried quite a few scalers and i have never found a perfect solution.In the end i returned back to RGB scart and CRT televisions for my Megadrive gaming needs.It looks georgeous but i can see the future benefits of these kind of solutions,and i know at some point i will have to invest again 🙂

  • Samastbury

    Use a CRT.

  • Awesome article! All is not lost for Mega Drive on a HDTV. And awesome site by the way. A real trip down memory lane.

  • Bruce Ironstaunch

    Strange, I can’t remember ever seeing scanlines on any old games. Just to make sure that I’m not remembering wrong, I plugged my Megadrive into my Two CRT TV’s (32″ and 18″, both PAL), And scanlines show up on neither.

  • Geert_Hermans

    I very much like to keep 2D games as pure and close to the original as possible, which is why I usually stay the hell away from stuff like 2xSai, HQ and various other image scalers on emulators. However, simple interpolation or full-screen anti-aliasing makes things much more pleasant on the eyes. I see little need for anything beyond that, but it is a matter of taste.

    Now, to deliberately put in scan lines, which were the result of CRT monitor restrictions, just for the retro feel, seems really over the top to me. I’d understand if games used clever graphics design tricks to use this to their advantage, but I’ve never seen any sort of sprite or background work where this is the case. Investing in this expensive hardware when emulators usually have a variety of well-performing scalers and scan line effects available also seems pretty superfluous. Anything that isn’t almost perfect emulated (things above 32-bit and Saturn) will usually look better without the scan lines.

    Regardless of preference, what I’m wondering about here is the introduced delay. Most HD TVs have a pretty big delay, even when the processing is kept to a minimum. I’ve connected a laptop to my full HD Sharp with HDMI, in game mode, duplicated the desktop, ran a stopwatch application and then took a picture. On average there was a 0.1 second discrepancy. Did the same via a VGA cable (with a VGA signal, HD TVs tend to bypass a lot of digital image processing) with the same result.
    One tenth of a second may not seem much, but it is downright lethal for things like bullet hell shooters and any high-level player of fighters will tell you it’s way too much when just a few animation frames may be your timing window for certain moves. So chaining a couple extra image processing nodes between a console and a HD TV sounds like it might push the lag into the unacceptable.

    I’m not certain how fast these things are, or how expensive, but I’ve got the feeling it might be better to invest into something that has virtually no processing delay, like a big computer monitor, and the necessary connectors. Or some specialized display that is intended for showing images with minimal delay.

    • Geert, you make a few good points about the delay, which I should have mentioned in the article, but as you say, it’s all a matter of taste, but I haven’t played one game through the scanline hardware were the slight delay was an issue.

      I would never play a Mega Drive or PC Engine game on a new LCD TV screen without some form of scanline addition because I feel that the pixels become too big, too blurry at the edges, and doesn’t look or feel right for 8/16-Bit gaming.

      The addition of scanlines helps break up the blockiness of the pixles, and the blurring of the edges from the new TVs own inbuilt scaling and interpolation of the image (this is something that can vary in quality between TVs).

      Scanlines still work well with Saturn and Neo Geo hardware, even with Dreamcast. Personally, I think the graphics look much more arcade like with the lines. Again, personal preference.

      When I play emulators, I turn the scanlines on, and never touch the 2xSAI, like yourself. But that’s for emulators, I always prefer to play the real hardware, with scanlines. 🙂

      • Geert_Hermans

        Well, these days it’s pretty much only my laptop that’s hooked up to my TV. So it’s easy to have the software/graphics card deal with any image processing and just pump a full HD image to it, so it won’t try too much funny stuff. I’ve still got a whole collection of Dreamcast games that need playing, so once I hook that up, chances are I’m in for a shock. I really like the fact that hardware like this is being made. It shows people will always continue to invest in keeping old games playable.

        • I’ve found with the Dreamcast, and old 4:3 ratio Dell LCD montior, with an SG-3000 scanline adder makes the games look fantastic. Arcade like! Again, totally personal preference. Thanks for your comments, Geert!

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