Path: utzoo!attcan!uunet!spool.mu.edu!uwm.edu!linac!att!cbnewsh!rkl
From: rkl@cbnewsh.att.com (kevin.laux)
Newsgroups: comp.multimedia
Subject: Re: DVI questions
Message-ID: <1991Feb28.141127.17012@cbnewsh.att.com>
Date: 28 Feb 91 14:11:27 GMT
References: <1252@prlhp1.prl.philips.co.uk> <1991Feb27.222824.6451@rick.doc.ca>
Organization: AT&T Bell Laboratories
Lines: 56

In article <1991Feb27.222824.6451@rick.doc.ca>, andrew@calvin.doc.ca (Andrew Patrick) writes:
> 
> We just got the new ActionMedia boards in (Capture & Playback) and are
> beginning to experiment with capture quality.  It looks like the 30 fps
> capture will be usable if you use a smaller playback window (say 1/4
> screen), but it is pretty ugly at full screen.  However, our testing
> has been limited at this point.
> 
> We have also found that with this new 2-board set that if your video
> source is anything other than a directly-connected camera, you are
> going to need a time-base corrector.

	This is for the most part true, but not because of any fault on the
part of the video digitizer.  VTRs and VCRs have the notorious, ah, *feature*,
of providing crummy sync signals, thus requiring the TBC.  I have had no
problem capturing CGA graphics though (from an old analog based version of my
CPS workstation, preserved digitally for posterity :-)).

> Now a question:  
> 
> When you install both the capture and delivery boards, you actually
> plug your VGA monitor into the Capture board, and link the VGA board,
> Capture board, & Delivery boards together using ribbon cables.  This
> works fine if you want the DVI playback to be on the VGA screen (you
> can even overlay your DOS text on the DVI images).
> 
> But, how are you supposed to connect a standard NTSC screen and use it
> for playback of the DVI images?
> 
> All you have left is the VGA connector on the Delivery Board and the
> VGA connector on your VGA card (which is terminated).

	On page 3-2 of the ActionMedia 750 Board Installation Guide, there
is a discussion about how to connect an analog 60 Hz RGB color monitor that
can accept TTL sync in NTSC format.  You will need to get a 9 to 15 pin 
adapter cable (not supplied).  The pinout for the 9 pin side is given in
Table 3-1.

	Regarding the VGA connector on the VGA card - in a development
environment, you will need a monitor connected to it as well as the capture
board, as most of the DVI production tools need dual screens, one for DVI and
one for VGA (the monitor connected to the capture board has three basic modes:
DVI only, VGA with DVI underneath, and VGA only).  In a delivery environment,
ie. no capture board, a single monitor is connected to the DVI delivery
board.  If the VGA connector on the VGA card has nothing connected to it,
ie. it's unterminated, when the system boots, the VGA card will come up as
monochrome only.  That's why Intel provides the VGA terminator, a hardware
solution.  But it is *NOT* necessary, because there is a software solution.
I have a little program that resets the VGA card back to full color operation.
I may post it here if there is enough interest.

-- 
________________________________________________________________________________

	R. Kevin Laux				Email: rkl1@hound.att.com
	AT&T Bell Labs				Voice: (908) 949-1160