(click here for the archived original version of the scanlines demystified website)

 

~ page last updated on march, 9th, 2013 ~


 

 

 

Seven years ago (in 2006) I created a little website called Scanlines Demystified. It dealt with my discovery that a certain line of scan converters, called Emotia from broadcast equipment manufacturer Extron, can not only downconvert VGA signals to 480i NTSC signals, but also convert VGA to non-interlaced 15khz signals, so called 240p signals. This was especially interesting as it could be used to convert signals from a Dreamcast, a XBox (or XBox360 for that matter) or a PC running MAME into genuine low-res signals which look excellent on classic arcade cabs or RGB monitors.

The site became a of huge success, prices for the Emotia units exploded and the surrounding technology advanced. In the past seven years a lot of players moved on, switched from their classic CRTs to LCD or plasma displays and started using upscalers to get better quality from their vintage gaming systems. If you're reading this, chances are good, that you've been to my
main site about deinterlacing and upscaling in general .

With upscalers like the
Micomsoft Framemeister, it's hard to justify keeping a bulky CRT around for classic gaming. Many of us don't have the space (or the willing girlfriend)  to keep multiple monitors or TVs on hand. Tech has advanced and quality with upscalers like the XRGB-Mini is terrific. Two years ago Jochen Zurborg introduced his SLG3000 - a little gadget which let's you add scanlines (those black lines between pixels which you can see with low-res video games on a CRT) to every analogue VGA connection. Since then, scanlines emulations has become affordable for everyone. CraftyMech's MiniSLG is just $20 and Yosi's Hanzo for the Dreamcast adds a scanline engine directly into the VGA box.

But despite all this, there's still a certain core-audience, which prefers "the real deal", either in the form of a
dedicated arcade cabinet or by keeping classic CRT monitors around. Size apart, CRT monitors still deliver fantastic picture quality for all vintage video game systems and don't require any expensive upscaling devices to make the picture look great. You just have to pick the right display. Unfortunately many of the newer systems, starting with Dreamcast or PS2 and ultimately ending with systems like the 360, don't output the native low-res signals you need to achieve the best quality on those monitors or cabinets. In order to get perfect 15khz quality from those, you need to downscale the system's 480p output to 240p. This page is dedicated to this very problem.

 


(some real hardware scanlines - a 240p source running on a Sony BVM monitor)

 


 

 

For 60+ years now, since television has been around, classic standard definition is transmitted as an interlaced signal. In the USA and Japan that's called 480i (running at 60Hz), while it's 576i in Europe, parts of Asia and parts of South America (running at 50Hz). When the first video game systems emerged in the 70s, both as arcade cabinets and as home systems, manufacturers opted for an alternative video standard instead. Instead of alternating the lines between fields, they chose a non-interlaced signal, delivering 60 progressive frames per second instead. To keep the format compatible with the millions of TV sets out there, each frame consists of (roughly) 240 lines - same as the fields in the interlaced signals. The progressive signal eliminated flicker, made text more readable and ultimately created what is known today as "8-bit and 16-bit pixel art".

Because the tubes were initially created for interlaced signals, the spacing and resolution of the tube's mask is optimized for 480i signals. If a progressiv 240p signal is fed, every second line is left blank, creating those visible dark lines, which we call "scanlines". Those lines soften the pixels and create a very distinctive look, which many people prefer to the "emulated" look of raw low-res signals on digital panels.

All the classic home systems out there, starting from early 80s Atari systems, mid 80s Nintendo and Sega systems, early 90s 16-bit systems like SuperNES, PC Engine, Mega Drive or Neo Geo, up to the early days of the 32-bit generation with Playstation One and Sega Saturn, output 240p signals (or 288p in their PAL versions) and are perfectly fitted for any classic CRT display. While the actual active lines differ on this systems (Neo Geo for example has 224 lines), 240p refers to the progressive nature and the 15khz timing of those signals.

With systems like the Dreamcast and Playstation 2 the dark days of interlaced video gaming came upon us. Many brilliant gaming achievements (like Namco's Ridge Racer V) only offer 480i output, which creates a flickery hi-res picture on classic CRTs and requires complicated deinterlacing on LCD or plasma sets. Unfortunately some TV manufacturers also dropped their 240p support for component signals on some of their TV sets (Samsung comes to mind), forcing video game companies to adapt 480i as their standard signal as well. Especially many of the classic compilations like Taito Memories or the Capcom collections only offer 480i output, although all the games included were originally running in 240p.

Luckily the Dreamcast, the XBox and of course the XBox360 offered 480p output as well. DC and 360 through official VGA cables, XBox through transcoder solutions like the Neoya VGA box. This allows to run games in 480p instead of 480i. The flickery interlaced image is replaced by frames with doubled resolution: 480 lines, 60 times per second. With a matching monitor (either a 31khz CRT, a LCD or a Plasma set) this allows for superb picture quality. For classic low-res titles a scanline emulator can be added for optimized looks.

 


(some emulated scanlines - a 480p source running through a SLG3000 on a Sony LCD monitor)

 


 

 

 

As everybody can see, it's easy to get great results on classic CRTs with sources running in 240p and it's easy to get great results on LCD and plasma sets with 480p sources, but what if we have a 15khz CRT with a source running in 480p ? All the major systems output in 480i through RGB or component. You can directly connect those systems to any CRT and get a picture. For low-res games that's ufortunately not what we want. We want 240p signals to achieve that great low-res "scanlined" look as seen above. This is where machines called scan converters come into play. Scan converters from big companies like Extron or Kramer were originally created to get graphics created on a PC workstation into linear editing systems (running in SD). They usually take in PC signals (VGA or XGA) and output NTSC or PAL in broadcast standard signals (480i and 576i). While it's cheap and easy to find a scan converter which outputs 480i, there are just a mere handful of devices to create a genuine a 240p signal.

With different devices, you get different approaches on how a 240p signal is created from a 480p source. Some devices simply kick out every 2nd line, others average two lines into one and a third approach (kinda different from the rest) turns 480i fields into 240p frames by shifting the line existing line offset. I'll take a look at this further on. The units I'll have a look at are:

-
Ultracade UVC (Ultimate Video Converter) (very hard to find, 2nd hand prices around $150)
-
Extron Emotia series of scan converters (2nd hand prices around $50 to $150, depending on model and condition)
-
Mimo Genius II converter (available new for EUR 250)
-
Extron VSC units (scan converters with 480i output, which can be converted to 480i with a little trick, $70-300)
-
Extron RGB interfaces (for tweaking UVC and Emotia setups as well as for straight 480i to 240p conversion, $30-50)

 


(480p source downconverted to 240p using an Extron Emotia - displayed on a Commodore RGB monitor)

 


 

 

 

 

The UVC (Universal video converter) is a little PCB made by Ultracade and mainly sold through Happ Controls a few years ago. It originally retailed at US$225, but is now completely sold out and very hard to find. Second hand prices range around 100 EUR ($130) as of early 2013. The UVC has a standard molex power connector, a standard HD15 VGA connector as a video input and a non-standard 6-pin output connector (similar but not identical to a Modu-1 connector). The UVC accepts VGA, SVGA and XGA at 60Hz and outputs 240p from all of these. It is recommended to input 480p, as this makes the downscaling much easier.

On the PCB there's a set of dip switches with allows to choose the sync polarity, composite and seperate sync signals and to configure the output between 15khz (240p) and 24khz (384p). This whole page focuses on the 240p capability of the down converters. 384p (24khz) is an alternative to display genuine hi-res material (games running in real 480p) on a classic dual-sync arcade cab. The resulting picture doesn't have the scanlines we want for low-res material, but maxes out the resolution classic tubes can deliver. For example: if you want to run Guilty Gear XX (a genuine 480p title) on a Astro City cab, but you dislike the flickering 480i option, 384p is the way to go!

Set to 240p output, the UVC delivers a very nice picture. The voltage levels of the output signal are configured for arcade use, so for home use, the RGB signal has to be run through a resistor array, otherwise the picture will be too bright. With a 480p input signal, the UVC averages every two adjacent lines into a single one. The UVC starts with line 2 and merges it with line 3. Line 4 gets merged with line 5 and so on. Without further tweaking (see below), this can result in slightly blurred edges and a certain loss of detail. With 24-bit color input, the UVC's output can show some solarisation effects (color banding), which is caused by the internal's A/D filter. This is something you might notice on the 360's dashboard, but it's never been an issue within a game.

An
old review can be found here, the manual can be downloaded here and a discussion thread on the UVC can be found here.

 


(resistor array used to bring the video levels down to proper consumer levels -
required if the UVC is used on a television setup instead of an arcade cab)

 


 

 

 

 

The Emotia is a whole series of scan converters by braodcast equipment manufacturer Extron. The original Emotia was introduced in the mid 90s, followed by various other models. The only versions to feature 240p output are the Extron Emotia, the Emotia Plus, the Super Emotia and the Super Emotia GX. Other models like the Super Emotia II or Emotia Xtreme have dropped their 240p capability. The Emotia series was succeeded by the VSC series (see below). There's a very early Emotia model available without any front control buttons and while I never had such an unit, I would suspect that it's locked to 480i as well, so stay away.

The Emotia processors were very expensive, ranging between $1,500 and $2,500. If you go shopping for an Emotia today, expect to pay between $50 (original model without power supply) and $150 (Super Emotia or GX with original power supply). If you find an unit without power supply, grab it nevertheless. While it's very hard to find a matching power supply (you need +12V, -12V, +5V and the proper pinout), it's very easy to build one on your own. Easiest way is to get a FlexATX power supply and just build a matching adapter cable. Pinout of the power connector and other resources
can be found here. Compared to the small UVC boards the Emotias are huge (about 9 times the size of an UVC), but on the other hand you get a nice enclosure and proper output connectors.

The Emotia units have a male HD15 input, a HD15 passthrough output and a set of BNC connectors to output RGBs signals (the GX models can also output component video). On the front the Emotia's output can be switched between PAL and NTSC, underscan and overscan and 480i, 480 with anti-flicker and 240p (non-interlaced switch position). Basic screen centering functions are available as well. Contrary to both the UVC above and the Genius II below, the Emotia can only output in 15khz (both 480i and 240p), not in 24khz (384p)

With the front switch set to 240p output, all the Emotias units output a perfectly fine low-res image. Output levels are already on a consumer level, so no further resistors are neccessary in the RGB lines. Just like the UVC, the Emotia averages two adjacent lines into one and it also starts with the second line, so expect some bluriness on the detail level unless tweaked with an input interface (see below). To my surprise the Super Emotia GX behaves slightly different, as it started merging the lines with the 1st line, resulting in a sharper image without further tweaking. The SEGX is the only Emotia model to do this. Again 24-bit color inputs can show slight solarisation effects, but the actual low-res 240p image is awesome.

 


(Dreamcast and XBox running through an Super Emotia GX, output to a Commodore RGB monitor)

 


 

 

 

 

The Genius II is a rather fresh find and I only reviewed it a few days ago for it's upscaling purposes. A full review of both the Genius and the Genius II can be found here. The Genius II is the only down converter with 240p to be easily available new. While rather pricey at 250 EUR, it's performs excellent and sets itself ahead of both the UVC and the Emotia units.

The Genius II comes in a heavy duty steel enclosure, it's powered through a custom +12V connector and features HD15 VGA connectors for both it's input and output (6-pin custom connections are available as well). The Genius II features an on-screen display for basic adjustments, but aside from setting the correct output resolution with the buttons on the machine itself, there are no adjustments neccessary. The Genius II can also be used as a upscaler - that's why it's important to set the output resolution to CGA (240p) before powering up the monitor. Of course the Genius remembers the output resolution when power cycled. Just like the UVC, the Genius II also supports 24khz output in 384p (read about it above in the UVC's introduction).

Different than both the UVC and the Emotia the Genius II does not average two lines for it's 240p output, but rather simply throws out every 2nd line. From my experience, that's not a bad thing (since the Genius doesn't feature 480i output anyway), but solves the problem with the blurry edges without further tweaking. The Genius's output is razor sharp with perfect pixel alignment. The Genius II is a rather new product (it even features HDMI output for it's upscaling capabilities), so it comes as no surprise that the unit's A/D section is much better than the UVC's and Emotia's with zero solarisation effects visible even on hi-color gradients.

 


(Genius II in action. Source is a 360, output above to a Sony BVM, output below to a XRGB-Mini)

 


 

 

 

 

The Extron VSC series was the successor to the Emotia series. Extron started with the rather bulky VSC-50, 75 and 100 units and eventually created smaller units (VSC-500 and 700). Some others like the larger 300 and 900 units are available as well. Compared to the Emotia series, the later VSC units have a fully digital control set, offer color bars for setup and several memory slots to save settings. They also offer several anti-flicker settings, one even mimicking a 240p output, but in all cases, their output signal stays at 480i.

You might wonder, why I care to add the VSC series to this page. Well, first of all the VSC units allows downscaling from higher resolutions like 720p or even 1080p along with geometry controls. And second the 480i output can be changed to 240p by adding a RGB interface (see below). The geometry controls can come in handy with newer classic titles like Super Hang On on the 360, which doesn't support 4:3 output on it's own. By using the VSC's geometry controls, titles like this can easily transformed into 4:3 for use on a classic CRT. Other companies like CYP or Kramer offer high-end scan converters as well, but I haven't tried those and I kinda like Extron :-)

 


(Super Hang On running on a 360 and converted to 4:3 480i using the VSC's geometry controls)

 

The newer VSC units are easily 10 years younger than the first Emotia units, so it's no surprise, that the actual conversion of the VSC units is top notch. It doesn't really matter if you input a VGA signal with a mere 480p resolution of a Full HD signal with 1080p, everything gets converted in top quality. Buying a VSC is easier as well. First they got internal power supplies and second they're easily available on sites like ebay.com. Expect to pay around $50 to $300, depening on the model. Models equipped with digital SDI output are more expensive and that's nothing we need.

 


(Output of an VSC-700 unit, 480i on the left, tweaked 240p output to the right, both to a Sony BVM monitor)

 


 

 

 

 

So, what's all this talk about magically tweaking the UVC and Emotia units ? And what's a RGB interface anyway ? Well, Extron's RGB interfaces are usually meant for remotely connecting a PC or notebook to a projector. Imagine a classroom with a beamer mounted in the back and the professor standing in the front connecting this notebook to a locally mounted RGB interface instead of directly to the beamer. Most the RGB interfaces have a set of BNC outputs for running long cables and one or more HD15 VGA input to connect a local source.

There are at least two dozen of different interfaces from Extron. Small ones like the 190, bigger ones like the 580, others with multiple inputs like the 203 or multiple outputs like the 164. The cheaper ones start at $20, while the bigger ones can be $100 and more. On eBay just search for "Extron RGB" to get a variety of interfaces listed. All of the interfaces do sync processing and can be used to convert a 480i signal into a 240p one (more on that below), but only some have a vertical picture shift and that is what's needed for tweaking a UVC or Emotia unit.

So, let's focus on the tweaking first: as said above, both the UVC and the Emotia average two input lines into a single output line, but unfortunately they start with line 2 and merge it with line 3. If you imagine a classic low-res titles running line-doubled on a 360 (imagine Mushihimesama Futari or ESPGaluda II), lines 1 and 2 are identical and so are 3 and 4 (and so on). Merging lines 2 and 3 on the other hand, causes a certain bluriness and lack of sharpness. Many titles (like Futari) can be adjusted with in-game options: by moving the screen one line up or down, you'll notice a visible increase in sharpness. If your source can't be adjusted, you can use one of the Extron interfaces (with vertical shift) to do this externally. Just put the RGB interface between your source and the UVC/Emotia and shift the signal using the centering controls. This will oh-so magically increase the sharpness of your output a lot !

 


(output from an Emotia, untweaked on the left, tweaked pixel alignment on the right)

 

The Extron interfaces can also be used for a completely different approach: using a sync processing dip switch on the back, an incoming 480i RGB signal can be converted to 240p by adding a simple line offset. This simply tells the monitor to remove the line offset between the fields, handling the interlaced fields like progressive frames instead. This is by no means an official feature of those interfaces, but merely an accident, since the units were simply not created for interlaced 15khz signals. There are two caveats though: first this only works on CRTs which don't apply digital processing. It works great on arcade cabs, Sony PVM and BVM sets, most 90s TV sets, but likely not on newer TV sets and not if you want to feed your newly gained 240p signal into another upscaler. Second, if your source isn't a linedoubled 240p title, but a true hi-res game, then the resulting image will be 240p, but it will show a certain amount of flicker. Still much better than actually connecting a 480i source directly to your monitor. Extron RGB interfaces require a clean sync signal, so a sync stripper might be required on the input side. This might sound complicated, but at only $20 for the cheaper interfaces, that's definitely the cheapest way to true 240p on your arcade cab.

The same conversion can be done with a scan converter's 480i output, for example one of the Extron VSC units I talked about above. You route your VGA signal into the scan converter and the scan converter's output into a RGB interface - again resulting in a 240p signal. By using the scan converter's anti flicker controls, the remaining flicker can be eliminated almost completely. Combining a scan converter like a VSC-700 with a RGB interface gets you a powerful combo with a resulting image easily on par with the other machines listed on this page.

 


(ESPGaluda II - 360 - running through a VSC-700 / RGB 201rxi combo on a Sony BVM monitor)

 


 

 

 

While it's easy to pick and recommend an upscaler (basically just a question of cash available), it's really hard to pinpoint and recommend a certain down scaling solution. I think the above machines should be split up into two sections: first the two units which can not only output lovely 240p, but also 384p for the best possible hi-res picture on a dual-sync monitor. If you require 24khz, either try to get an Ultracade UVC or buy a Genius II unit. The Genius II has the best "out of the box" quality for 240p output, while the UVC can (and should be) tweaked by adding a RGB interface with vertical shift. While the UVC is extremely hard to find by now, the Genius II is easily available (but at it's price). Emotias or the VSC approach are good for 240p output only.

On the other hand there are the two cheap solutions: first the alternative approach (480i to 240p) by using just a RGB interface and second getting a cheap Emotia unit off eBay (likely without power supply). One's good for converting 480i directly into 240p (which can be nice if your sources are just video game systems and you know what a sync stripper is), while the other's your best shot, if you have a 480p-only source like a PC running MAME. Again the Emotia should be tweaked using a RGB interface with vertical shift. Using a real scan converter like the Emotia is much more versatile though.

If you don't mind using two machines instead of one and possibly already have a RGB interface at home anyway, the newer VSC units do a nice job with their anti-flicker controls and the added 480i to 240p conversion looks almost as good a genuine 240p output an Emotia. Compared to a unit like the Genius II, that's certainly not plug'n'play anymore, but the results are rewarding and price for a VSC / RGB interface combo is rather modest.

If you don't mind the price, the Mimo Genius II is the most advanced unit in the bunch with perfect 240p results and the possibility to drive a 24khz monitor within an arcade cab. If you plan on using any of those down scalers with a consumer TV set, make sure it can be manually set to it's RGB input. None of the units introduced above deliver a switching voltage required by many scart connectors to enable the TV's RGB mode. The neccessary switching voltage can be supplied using an external power supply or a battery. Ask your tech-savy neighbour or your friendly video game board for advice !

Of course I can be reached
via email as well.

 
 

(C) Tobias "Fudoh" Reich, 2006~2013
last updated on March 9th, 2013

 
 

 

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