V-Box

From: Steve Judd (sjudd_at_ffd2.com)
Date: 2000-08-24 05:04:10

Hello Hackers!

As you may recall, the V-Box is a device for hooking up an NTSC/PAL source
to a VGA monitor.  I received one today, and thought you might like a
mini-report.  Note that there are several other similar devices out there,
like Jam!!, but I have no experience with them.

The box is fairly small, smaller than a 5.25" disk -- about the size of a
walkman.  It has inputs for S-Video, RCA composite, and stereo RCA audio
plugs; it has two outputs, on for a VGA monitor, and the other for a PC
VGA card.  There is also a small pushbutton switch for PC/Video/S-Video --
the exact purpose of this switch isn't clear to me, as there is no PC
input and there is no Video/S-Video output.  There are no instructions,
except for what is printed on the box.

My main reason for buying this device was to see my PAL C64 in color.
Unfortunately, using the composite cable, I didn't get color -- just
grayscale (a kind of dithered grayscale, actually -- more below).  So it's
possible that a) S-Video is needed, b) my machine doesn't actually display
color properly, or c) the V-Box doesn't convert PAL color correctly.

So I hooked up an NTSC machine -- hey, color!  The display is much sharper
than a 1084 -- for example, a diagonal hires line really looks like a
straight line, instead of a staircase, and colors are solid.  Interlaced
pictures (mcm-lace, IFLI, etc.) look quite nice.

There are a few oddities, however -- most likely due to the way Commodore
generates the color signal.  Scrolling things sometimes look strange, with
flickering pixels (flickering between two colors).  Edges between certain
colors also look "interlaced" -- for example, a solid brown bar on top of
a blue background.  The edge of the bar looks "fingered", with every other
raster line sticking out a few pixels.

Similarly, sometimes dithering two colors next to each other produces a
completely different color.  For example, some dithered graphics just come
out black.  Again, I think this is due to VIC cramming two pixels into a
single pixel clock (or whatever it is that he does), so that the signal
isn't _quite_ right.

And some colors, notably the PAL grayscale "colors", actually look 
dithered, with every other pixel being a different color (for example,
the blinking cursor).  Using the separated luminance signal gives a
uniform shade of gray with the PAL machine.

I will have to build a split/S-video connector to test the S-Video
input -- anyone have the pinouts for a round, 5-pin S-video connector?

Overall I think it's kind-of neat, and while I really wish I had color
PAL, the picture really is nice and it's nice to be able to use a 64
with a VGA monitor -- I expect VGA monitors to be cheap and available long
after 1084s wear out.  I also expect that the picture will be quite nice
on a great big VGA monitor, too.

Cost was about $70 US.

-Steve

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