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From: john@bby-bc.UUCP (john)
Newsgroups: comp.sys.ibm.pc,comp.graphics
Subject: Re: Info regarding Targa Board for IBM-PC
Message-ID: <173@bby-bc.UUCP>
Date: Fri, 20-Nov-87 01:36:36 EST
Article-I.D.: bby-bc.173
Posted: Fri Nov 20 01:36:36 1987
Date-Received: Tue, 24-Nov-87 00:43:47 EST
References: <2075@unc.cs.unc.edu>
Organization: Burnaby, British Columbia, Canada
Lines: 22
Xref: mnetor comp.sys.ibm.pc:10398 comp.graphics:1415

In article <2075@unc.cs.unc.edu>, bmh@unc.cs.unc.edu (Brad Hemminger) writes:
> 
>   We are considering the purchase of a Targa 16 (AT&T) graphics board
> for use in an IBM PC.  The major use will be to digitize every n frames
> from a VCR tape, do some image processing on the frames and save info
> to the hard disk.

I use a targa-16 on an AT and find it quite a nice board.  If you mean
you want to digitize n contiguous frames at a time you won't be able to
do it without putting some identifying mark on each frame and reading
the tape n times since you can't read the info out of the frame buffer
as fast as it comes in with realtime video (it takes about 5-10 frame
times to read out the buffer).  If you want every n'th frame then there
will be no problem as ong as n is reasonably large.  Of course maybe
you are using a frame-by-frame vtr in which case my comments don't apply.

Also if you use the targa to capture fields you should know that what
you get is odd field even pixels, odd field odd pixels, even field even
pixels, even field odd pixels - i.e. there is no superposition.

hope this helps,
		john