Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!oliveb!ames!ucsd!brian
From: brian@ucsd.EDU (Brian Kantor)
Newsgroups: sci.electronics
Subject: Re: What causes this?
Message-ID: <49@ucsd.EDU>
Date: 26 Feb 88 05:51:07 GMT
References: <5580@burdvax.PRC.Unisys.COM>
Reply-To: brian@ucsd.edu (Brian Kantor)
Distribution: na
Organization: The Avant-Garde of the Now, Ltd.
Lines: 22
Keywords: TV picture breakup

Because there's no convenient way to send synchronization signals out to
field cameras from the central time base generator, it is common
practice to process the signal through a digital framestore.

The field signal is used to clock the image into the image memory at the
sync that comes from the field camera, and then the image is clocked out
of the image memory at the station (or production van, whatever)
standard sync rates and timing.

So if the signal goes away, the input clocking can be stopped, and
you'll just continue to repetitively get the last good frame.  You could
override that and clock noise into the framestore, but why would you
want to?

There exist a couple of models of digital framestores that are N seconds
deep, instead of a couple of frames.  These are just the ticket for
instant repeat action, and for editing something (like a 30 second
commercial) that will fit, they are really superb.

	Brian Kantor	UCSD Computer Graphics Lab
			c/o B-028, La Jolla, CA 92093
			brian@ucsd.edu