A common question we were asked during our time at VGU was how our cables worked. The actual implementation is somewhat complicated, but the concept is quite simple and can easily be understood by all.

Several consoles released in the 80's and 90's had proprietary connectors for the audio/video outputs.  If you were like me at the time, you got frustrated with these things. I know I was relieved when my launch Playstation 1 provided discrete A/V connections so I wouldn't have to deal with Sony's special connector.  It turns out that these seemingly annoying A/V connectors contained more than just the standard composite video (yellow) and stereo audio (white/red) we were used to.  In some cases, there were pins on those connectors which provided an s-video signal for improved picture quality on TVs with such a connection.  And that's it, right?  Well, yes, it was for us living in North America.  But out in Europe, all this was a sideshow to what was actually possible.


To understand the following, you need to be familiar with a very simple concept.  A display, such as a TV, shows an image by combining light in red, green, and blue (RGB) components.  A source, such as a camera, takes light in and splits it up into its RGB light components.  A different type of source, such as a computer graphics system, generates RGB signals directly instead of capturing them.  For optimal quality, you want this path from source to display to be as direct as possible.  Any deviations from this path can result in artifacts and visible errors on the display.  For example, to create composite video, the RGB needs to be heavily processed and combined into a single video signal. The processes involved in combining and then separating the video back into RGB causes a major deviation in the ideal path, hence the sub par quality achieved with using composite video.  The following diagram attempts to visualize this detour that composite video takes in relation to a direct RGB connection.


Back to the consoles.  Almost all of those funky A/V connectors had pins containing the raw RGB video generated by the graphics system of the console.  And in Europe, TVs have special inputs that can accept and display those signals.  They did this through a special connector on the television called SCART.  The connector was very large with many pins and incorporated several features to simplify A/V equipment connections.  Think of it as the analog precursor to the digital HDMI connection we are all familiar with these days.  With a special cable that connects the console RGB pins to the SCART connector, you can achieve an almost perfect source-to-display connection.


For us in North America (and several other parts of the world), we never had TVs that could accept these raw RGB signals.  But what about those red, green, and blue colored RCA jacks commonly found on our TVs?  Although physically colored that way, those are not RGB inputs, but they are very close.  YPbPr (or "component") video is only a simple, reversible transformation away from RGB.  So the idea is to perform the transformation for the purpose of using a compatible input on the TV.  Then, the TV will undo the transformation to recover the RGB and display it.  Below is one page of my engineering notebook which begins to explain the theory behind our product.  The diagram on top of the page illustrates the concept I've just explained.


Some people say that you're just as good in getting an RGB SCART to YPbPr conversion box.  Disregarding the hassle and cost involved in dealing with conversion boxes, I still don't believe this is true.  We've spent lots of time here at HQ researching the RGB video signals coming out of both the SNES and Genesis consoles.  By using custom test software, the signals were accurately measured and we've determined that these consoles are not properly designed to follow any particular standard.  These video signals can be too dark, too bright, have slanted lines (field tilt), and contain unwanted noise.  These problems are compensated for within our cables. Think of our cables not only as simple plug-and-play conversion devices, but also as "signal conditioners" to achieve the best possible output from your consoles.

Like always, if you have any questions, please feel free to contact us via the contact page.  Also let us know if you like these more technical blog posts and if we should do more of them.

AuthorSte Kulov