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From: steve@bambi.UUCP (Steve Miller)
Newsgroups: net.graphics,net.micro.pc
Subject: Re: AT&T Graphics Boards Info--looking for review.
Message-ID: <513@bambi.UUCP>
Date: Fri, 29-Aug-86 14:48:49 EDT
Article-I.D.: bambi.513
Posted: Fri Aug 29 14:48:49 1986
Date-Received: Sat, 30-Aug-86 03:26:45 EDT
References: <306@axiom.UUCP>
Organization: Bell Communications Research Inc., Morristown, NJ
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Xref: mnetor net.graphics:1229 net.micro.pc:6331

> Has anyone out there tried any of these boards with or without AT&T's
> software?  I'm looking for a review.
> 
> Truevision Advanced Raster Graphics Adapter (TARGA):
> There are several versions of this board.  They all capture in 1/30s from
> camera or VCR.  Hardware zoom (2X, 4X, and 8X).  Smooth independent vertical
> and horizontal scrolling.  Bit-pane masking.  "Robust" gen-lock capability.
> Up to 512 x 420 pixel resolution depending on color depth and model.
              ^^^

The vertical resolution is adjustable; mine works fine at 483.

I have the TARGA 32 in my IBM PC, running my own software under the
QNX operating system from Quantum in Canada.

The TARGA is an excellent frame buffer for the PC.  It only uses 64k
of address space, partitioned into two banks of 32k (making screen to
screen copies possible).  In its standard configuration, the TARGA has
a non-broadcast horizontal blanking interval; there are black bands
to the left and right of the picture visible onscreen.  However, an
option is available to change the timing, making the signal broadcast
compatible.

The documentation is superb.  Many helpful routines are shipped with
the board (in Computer Innovations' dialect of C, though I've had
little trouble rewriting them for QNX C).  Between the two, it's been
very easy to get full function from the TARGA.  The frame grabber is
very accurate, with no perceptible h-shift or field locking problems.
The output signal is very clean; there are no transients at intensity
boundaries, and the picture is quite stable.

Two small problems:  With the exander option installed (to adjust the
blanking interval) the board is a little wider than one slot.  Also,
in my case, the genlock failed after several hours operation, due
to heat I suspect.  It works fine with the cover off the PC, and I
expect that an expansion box with a fan will solve the problem.

I have not found much use for the blend capability, and would have
preferred a graphics overlay channel instead.  I understand this is
being considered.

I have alot of software working with this board (z-buffer, utilities, etc.)
and would be happy to correspond with others about it.

		-Steve Miller ihnp4!bellcore!bambi!steve
		              Image Space Inc.
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