> James Tu wrote:
>
> > Has anyone ever used hardware that allows you to split one
> > VGA output from a graphics card into multiple monitors...such
> > as for a video wall.
> > I want to be able to specify, for example, a rectangle defined by
> > pixels (1 - 100)x(1 - 200) goes to monitor 1 and the rectangle
> > defined by pixels (101- 200)x(1-200) goes to monitor 2, and
> > so forth...these numbers are just examples.

I'm no video expert, but I reckon you could do this with micros.
Although my thinking is probably up the creek wrt to interlacing
and other technical vagaries. If picture-in-picture is doable by
a micro then so should video walling

It seems to me you don't need to monkey with the picture info
much, just direct it. Say you took the top left third of a display
(for example splitting the display over 3x3 screens). It will be
made up of pixels and lines. You could count the pixel clock
with a micro and direct, via a video switch, those pixels to
Monitor1. The middle third would go to Monitor2, the last 3rd
to Monitor3. Same for the next scan line, until you reach the
scan line that marks the end of the top third of the original
picture, then send pixels to Monitors 4 5 & 6, and 7 8 & 9 to
end

The tricky bit would be filling the monitors' displays. To do this
you would have to send 3 copies of the pixel and the line, so
expanding the 9th part of the original to a full screen width, in
the process reducing the resolution. But you can't display info
you don't have anyway

Sound OK, or should I wait for the other shoe to drop ? There
might be a "can't do" - maybe previously accessed monitors
need refreshing. I know people on the list have driven displays
with fast Scenix micros, perhaps it really is possible

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