Video captures comparing RGB and NTSC composite

This is Page 2 (Mega Drive). Click here for Page 1 (Other systems).

A couple of years ago, I took a cheap USB video digitizer out of storage to play with it, and figured out a way to capture RGB video from my various game systems. What I did was jerry-rig the digitizer, which normally accepts either composite or S-Video, to take as a luminance signal one of the R,G,B channels paired with a sync signal. This made for a stable image which could be captured for each of the R,G,B channels in sequence. For game systems that output only composite+sync, I had to separate the sync signal using an AV Demiro box which contained a sync stripper. The quality of the captures is quite good, with only a small amount of visible noise in solid colour areas.

Anyway, capturing RGB and composite using this method eliminates the need to take photographs of television or monitor screens, with no warping or phosphors getting in the way. Thus, much more direct comparisons between video outputs can be made as you can see below (by hovering your pointer over the images...) If you have any requests for specific game screens that you'd like to see compared in this way, send me a mail!


Sega Mega Drive

The Mega Drive gets its own page because of its notoriously bad composite video. Once I set up my digitizing equipment and took snapshots of a few games, I just got carried away and took pics of many of my favourite games. Or, I took pics of especially egregious examples of just how much the MD muddles, blurs, and confounds the composite video display to the dismay of its hapless users.

RGB video out of the Mega Drive is extremely crisp; however, it does have two disadvantages when capturing it: 1) The RGB channels have high voltage/current, so they're way too bright for a regular monitor and have to be brought down to normal levels with a resistor. Because they vary between high and low voltages quite quickly, digital->analogue "bounce" can be seen as ghosting following a particularly bright pixel. My RGB monitor doesn't suffer from any of this ghosting, but my capture card does, alas. Check out the Altered Beast ingame pic for some of this bounce in RGB.
2) One strange affliction of the MD's RGB is that the blue channel has vertical bands in the signal, running all the way down the screen. Everybody complains about it; nobody knows why the MD does this. Check out the blue shadows in the title screen of Altered Beast to see an example of this oddity.

Batman was used by EGM / Mega Play magazine to illustrate the superiority of RGB. This same scene in the game continues to this day to be a great example.

Dithering: You either love it or hate it. For a low-colour system that can't do transparencies (like the MD) dithering is a necessary evil, and the composite display of the MD conveniently blurs almost all evidence of dithering. RGB might come as a shock to some because all the dithering is laid bare.

Therefore... it takes real skill to draw stunning graphics without resorting to any dithering, like Henk Nieborg has done with Flink.

Hyper-saturated colours, especially visible in reds and yellows, cause terrible fringing & colour smear through composite.

Look at how the weapon text is just decimated in Midnight Resistance!

Even way back in 1989, I was constantly amazed how realistic-looking the ninja in the title screen was. Why couldn't later games with digitized graphics look this good?

Socket, a shameless Sonic rip-off, uses plenty of vertical-only dithering in gradients and to achieve a transparent effect in composite.

...unfortunately a side-effect of this vertical-only dithering ("transparency"), besides smearing, is a nasty rainbow effect:

That's all for now! I hope you enjoyed my extended visual rant on the shittiness of Mega Drive composite video!