Transfer Personal IRIS images to VCR

[Andrew Simms]

Mark Callow writes...
>	You don't need any other type of converter.  You need an animation controller
>	and a single frame VTR.  Display the frame, record it, and move to the
>	next one.
>	--
>	From the TARDIS of Mark Callow
>	msc at ramoth.sgi.com, ...{ames,decwrl}!sgi!msc

And my response is:  WAIT WAIT WAIT not necessarily.

There has been a bit of traffic lately about animation and so forth on the
net and most of it hasn't given the big picture on making animations. 
I get the feeling that a lot of people interested in making animations have
hit the same walls I did in trying to put together a system that works:

1.  Lots of products not marketed specifically at the sci-vi interest group
2.  Lots of sleazy video salespeople who have no idea why anyone would
	buy a 100k+ plus machine that doesn't run lotus but are more than
	happy to sell you something.

So, in a long nutshell, here is the big picture:

There are two major arenas in the animation field:  frame by frame and
realtime.  Frame by frame utilizes a device called an animation controller.
This box controls a high priced VTR called an editing deck.  It can cause
the VTR to record extremely short segments of video onto a tape.  The
net result is a film in the tradition stop action photography.  It can
produce beautiful results.

The second arena is called real time.  Here you record images from your
iris to a VTR as they are displayed.  This type of animation is excellent
for demonstrations and animations that are slow enough for your SGI to
display in real time.  This type of animation doesn't require an editing
deck, but the better deck you buy the better results you will get.

HARDWARE NEEDED.
What you need depends on what you want to do.  There are a couple inheirant
problems with animation and you must choose the right hardware to solve
the problems.  These are the problems:

1.  The Iris has a high resolution monitor/display.  Video decs are low
	resolution devices.  In order to display your Iris screen on 
	standard TV format device, you need to:
	A.  Reduce the resolution of the iris image to NTSC (TV), SuperVHS
		(a newer higher resolution standard), or another format
		suitable for your VTR.  This process requires a scan 
		converter (Lyon Lamb makes an expensive one, we ended up
		buying an RGB Technologies box).
	B.  Cut a small window out of your iris screen and transmit it to
		your VTR.  SGI (and other companies) makes a simple card
		called a genlock option that does this.  When this board is
		on the RGB lines going to monitor change from their normal
		high-res signal to RS-170, a low resolution RGB signal.
		I believe (but since I am at home and can't look, that
		a composite signal is provided as well).

2.  Are the movies you wish to make slow enough that your Iris can display
	the results in real time?  If not, you will need to go frame by
	frame.  For this, you need an animation controller.  There are
	several types.
	A.  Lyon Lamb and others make a NTSC/SuperVHS level animation 
		controllers.  These are meant to use low resolution
		images and as such you run into problem 1.  Some animation
		controllers will only accept a composite signal.  Therefore
		if you have solved problem 1 such that you only have RS170
		you may need an additional device called an encoder which
		will take the RGB signal and create a composite signal
		suitable for the majority of animation controllers.

		This class of controllers work in the following fashion.
		You feed the controller an appropriate video signal.
		The lyon lamb is controlled by your iris via an RS232 cable
		and it uses software you get to write yourself or purchase.
		When your frame is ready, you issue  a record command.
		Then you prepare the next frame, record, prepare, record...
		until it is done.

	B.  Abacus and others make a different type of controller.
		This device sits on your ethernet and has a 1.2 Gigabyte
		disk on it.  You write software that FTPs your image
		to the Abacus.  It stores sequential frames on disk, and 
		then it will write them out to a VCR.  I believe that
		the transfer is accomplished by constructing a frame
		on the Abacus's internal frame buffer then it issues a
		record command to your VTR while displaying the image.
		This is an expensive device.  You do not need a scan converter
		for this option but you will need an editing deck.  
		Perhaps someone can comment as to whether or not Abacus
		will provide a deck.  It should also be noted that this
		device cannot do real time recording.

	C.  SGI's new product.  SGI now has a card that is an animation
		controller.  It may only work on a Power Series (SGI 
		please confirm) and promises to be a nifty product for
		those who will only be using an SGI to make movies.
		It may also be capable of displaying video images on
		your high-res display while you work (so you can watch CNN
		while you work like all the cia folks).  I believe it
		can do both frame by frame and realtime animation.

SOFTWARE

We are writing our own for the stuff we bought, so I don't have much 
info.  It would make this message far more useful if someone would comment on 
what's available.

WHAT I BOUGHT

The group here needs to do both frame by frame and realtime animations.
We also decided we needed better than NTSC resolution so we went with
supervhs.  So, we got a Panasonic AG7500A 1/2" VTR, an RGB Technologies
Scan converter, a Sony 1342 s-vhs monitor and we upgraded our Lyon Lamb 
Mini-vas to the SuperVHS edition.  Our realtime results have been 
excellent. When we have our minivas back from upgrade, I will know about
frame by frame quality.

FINAL THOUGHTS

Insist on on-site demonstrations and/or have your dealer leave stuff
with you for evalutation.  Otherwise you will end up with a pile of
stuff you can't even pay graduate students to use.  As far as sources 
for this stuff, I will prepare a list and post it or mail it to those 
who are interested.
  

  Andrew Simms					ams at acm.princeton.edu
  System Administrator
  Program in Applied and Computational Math
  Princeton University
  Princeton, NJ   08544
  609/258-5324 or 609/258-6227
  609/258-1054 (fax)