[Coco] Re: again: CoCo RGB to VGA conversion

[jdaggett at gate.net]

The CM8 monitor can handle about 263 lines plus or minus about 
12 lines. 

james


On 24 Aug 2004 at 1:45, David J Bush wrote:

To:             	coco at maltedmedia.com
From:           	David J Bush <twixt at cstone.net>
Date sent:      	Tue, 24 Aug 2004 01:45:09 +0000 (UTC)
Subject:        	[Coco] Re: again: CoCo RGB to VGA 
conversion
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> > > It's hard for a converter to scale up a line to a fraction of a
> > > line, such as 1.5 lines (without some significant gray-level
> > > anti-aliasing). Let's see, the VGA has 480 lines.  Straight Coco3
> > > has 384, or 80%, so you have 10% of the total screen height blank
> > > at top and bottom.  Not too bad. RSBASIC and maybe even OS-9 can
> > > be poked up to 200 high, or 400 out of 480. Some BASIC hackers
> > > claim to have hit 225, or 450 out of 480. 
> 
> Where does the 384 come from? Is that vertical padding? With 225 lines
> to work with, that's 159 extra lines. Right? So the ideal thing for
> this conversion hardware to do, would be to snip out those 159 blank
> scan lines, and mutliply the usable 225 by a nice integer, namely 2.
> That would produce 450 scan lines, with a margin of 30 lines to fit
> within a 480 line screen. Piece of cake! :-)
> 
> Oh, and a switch to choose either the analog RGB signal or the
> composite signal would be nice. That way, users could have the best of
> both worlds, RGB for most apps, and composite for software which uses
> artifacting.
> 
> David
> 
> 
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