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View Full Version : Video splitter needed: summary of replys



Neil Glossop
05-24-1994, 12:34 AM
Dear Biomch-l readers,

Here is a summary of replys to date regarding my original posting
on video splitters. As I had received several requests for this
information, I am posting it to the list. Thanks to all who replied.

SUMMARY: This can be accomplished using a device called a special
effects generator, that provides quite a bit of functionality beyond
the simple split screen that I requested. These devices are in the
$1000-2000 range. In addition, several companies make dedicated screen
splitting units in the $300 range.

Neil

--
N. Glossop, Ph.D.,
Toronto, Canada

neil@isgtec.com

================================================== =======================
The original posting:
================================================== =======================

> Dear Biomch-l readers,

> I am looking for a "video splitter", a device used to combine
> images from 2 video cameras onto the same frame. These devices are
> used to simaltaneously display/record a sagital and frontal view of a
> gait study by splitting the video frame into two, placing the view from
> one camera on the left part of the frame and the view from the other on
> the right hand part of the same frame. The space occupied by each
> camera view is adjustable with some kind of knob, and they can also
> be switched to split the field horozontally.
>
> Does anyone know what this thing is called, or where to get it? How
> much are they?
>
> Thanks in advance,
>
> Neil
================================================== =======================
From: Connie L Taves

EDCOM MULTIMEDIA
1773 Mattawa Ave. Mississauga Ont.
(416)275-6010
-sells 2 channel video mixers for @ $2K.

SONY sells a base model mixer for around $700.

You do pay for the extra bells and whistles but they are sometimes really
worth having.

-------------
From: abraham@utxvm.cc.utexas.edu (Larry Abraham)

In the 'old' days, we called such devices "special effects generators".
I'm sure that they are available now in a variety of forms, including
having the effects generated in software (i.e. having the video signals
both fed into a computer). The SEG I have used was made by Panasonic about
fifteen years ago. I'll bet there are plenty of others like it collecting
dust in many institutions. Its only possible drawback for an application
such as yours is that it was black and white only. I have a six-year-old
catalog listing color SEG's for $500-800 from Quality Video Supply, P.O.
Box 1007, Hackensack, NJ 07602 (800)431-6000. Probably the price has
dropped since then.

Larry Abraham, EdD
Kinesiology & Health Education
The University of Texas at Austin
Austin, TX 78712 USA
(512)471-1273 FAX (512)471-8914
-------------

From: Paul Guy

Hi Neil,

There are such things, they are called video mixers, or video wipers
or just special effects boxes with 'wiper options'. The wiper options
determine whether the images grows in from the sides, middle, fades or
whatever. Watch out, a video 'splitter' can be something that takes one
video line and splits it into many other output signals of the same picture.
In order to use this wiper, the cameras MUST be 'gen-locked' or in
synchronization with each other. That means they must have an external
sync on at least one camera, so that it can lock onto the other. The
connections for gen-lock can be different from manufacturer to
manufacturer. It may drive you nuts.
Just about any supplier for video or multi-media stuff should be able
to supply something for you. Most of this stuff is too fancy for your
application, make sure you get just what you need. I wouldn't pay more
than $500 for one. I seem to remember Radio Shack selling some video
effects stuff, they may have one that mixes and wipes two cameras. "VAC"
is the brand of cheapy video stuff that we use. They are real simple,
and cheap. Some of the mixers may have synch outputs that you can also
use, but beware of whacky connector styles, epecially amongst Japanese
stuff. If you have one brand of cameras (Japanese) you will be almost forced
to buy their special effects stuff, unless you get into studio or
broadcast quality equipment.

-Paul

---------------
From: Deborah King

Dr. Glossop,

you are talking about a audio visual (a/v) mixer used in video editing. It
allows you to not only mix uually up to 4 video signals my using split
screens, some let you insert the image (s) from one camera into that
of another which means that you field of view is not decreased as it is
when using split screens. Any company whicvh makes A/v equipment will
have these. I have used Panasonics (two models - but I can't remember
the model #s) mixers and a Panasonic device which just does video inserting
(no split screen) I can't remember what this is called but it is not
really editing equipment. By the way, the mixers do not have to be
used just for editing, but work very well to run your video signal
through before the VCR to record a split scrren image. Contact

Panasonic
Industrial Co.
(executive office)
One Panasonic Way
Secaucus, NJ 07094

(canadian division)
Matsushita Electric of Canada
5770 Ambler Dr.
Mississauga, Ontario
L4W 2T3
(416) 624-5010

They will be able to send brochures on their various mixers and other video
equipment which will do split screens or inserts - hope this helps

---------------
From: kallesoe@sfu.ca (Klaus =?iso-8859-1?Q?Kalles=F8e?= )

Hi' Neil,

We are currently using an "old" (1985) video splitter (or rather merger),
that will do what you described. It's from Javelin Electronics, model
JSS4DA. Very simple unit, but probably not available any more. We bought
it from Avicom Industrial Communications in Calgary (403) 250-1947, but
they might be out of business. Try instead Anderson Com. (416) 660-4460,
or a Californian comp. at (310) 327-7440.

Good Luck


Klaus

---------------

Sender: "HowieDBPG"

Neil:

I just wanted to let you know that I have one of these and they work great
for video analysis. I am a podiatrist and perform gait analysis daily with
this. The system I use is now 8 years old and it has performed flawlessly
for immediate review. It is also remarkably helpful in examing motion. You
will be surprised by what you will see. I do not have the name of my unit
off the top of my head but I will send it to you when I get back to my office
on Monday.

The only difficulty I have had is when you try to copy a split image onto
another tape. Apparently, the split is created by dividing the number of
lines 50% on each side. This is fine to view on the original tape, but when
you try to copy it, the results have been unfortunately poor. Good luck.

Howard J. Dananberg, DPM
howiedbpg@aol.com

---------------

From: DLLUEDTKE@ALEX.STKATE.EDU


For your video spliter, could you be referring to a special effects generator
used in television and video production. this device will allow one to split
images in many ways on a screen and can combine signals from more than one
camera. i am not sure of the cost but I don't think they com cheap. Hope
this is helpful.

Dave Luedtke, College of St. Catherine

---------------
From: John Baker (Tel \(06\) 252-1558 )

20/5/94

Dear Dr. Glossop,

In regards to your inquiry on Biomch-L about a video splitter a
possible solution may be a video mixer. We use a mixer in our
lab primarily as an image splitter in the way you described.
That is the majority of the time we use the mixer to split the
final image from the input of two cameras either vertically or
horizontally.

The mixer also has other capabilities such as being able mix
different shape images into the final output. For example, one
camera may be used as the primary image while the second image
can be mixed in as a square or circle and positioned anywhere
within the field of view. The mixer can also be used to fade in
and out between the two cameras, but this in a characteristic we
don't use due to it really been an aesthetic function than
anything else. There are also a number of other functions which
are also primarily aesthetic in nature. These may be of use if
you are producing videos of any type for more general purposes.

We also use the mixer at times purely as a gen locking device for
3-D analysis. That is we feed the images from two cameras
through the gen lock aspect of the mixer and then into individual
recorders linked to each camera. This helps to overcome the
problem of reduced field of view and resolution if the cameras
are split for the one final image.

We use a super VHS JVC mixer, but all the major companies such as
Sony and National-Panasonic also make similar mixers.

The price of our unit is approximately AUS$6000. Our technician
is of the feeling that cheaper units would be available that
simply act as a video splitter in the sense that you are after.

Hope this is of benefit.

Regards,

John Baker
Biomechanist
Australian Institute of Sport
E-Mail: John.Baker@AUSPORT.TELEMEMO.AU

---------------
From: knoek@sara.nl

Dear Neil,

Such an apparatus indeed exists and is called (at least in Europe) a
'video mixer'). In our faculty, one was bought about a year ago for something
like USD1500. Panasonic and Blaupunkt are recommended manufacturers.
Three notes:
1. The Canadian situation is of course different to ours due to different
video standard.
2. Beware of the loss of spatial resolution that results from combining two
images on one screen (resolution of standard video is quite lousy to start
with!)
3. If you need additional information, contact Henk de Best, a technician in
our faculty... of whom I don't have the mail address. Contact me instead
and I'll find you the address.

Regards, Knoek van Soest, faculty of human movement sciences, vrije universiteit

---------------
From: "A.W. Smith"

Panasonic (Matsuishita) makes an AV Mixer which we use to both split-screen
and mix video images. It's more sophisticated than you probably need (and
more expensive); however, its a good place to start. Try Adcom Electronics
(one of their local distributers) in Toronto.


---------------
From: Jonathan Carmichael

Dr Glossop, we are currently using a beam splitter in our lab for
determining Poisson's ratio of cartilage.It cost in the range of
$500-$700 and is quite nice to work with as it allows for both horizontal
and vertical output. The address for this product is:
American Designs
10 Corporate Dr
Orangeburg, New York
10962
Product Model 1470A
Jon Carmichael

---------------
From: Nancy.Hamilton@uni.edu

Hi Neil -
I don't know where you can get a video splitter (that is what I have
always called it, too), but I do know that the Educational Media people at the
University of Illinois built one a number of years ago. I don't know how
difficult it was to put together, but the biomechanics lab there used it a
number of times with great success. You might see if there is anyone on-line
from the U of I and ask them to check it out. I have lost touch with them, so
don't know who to call. If you would like to pursue this, let me know and I
will do what I can. You may get many other replies that offer more immediate
help. Good luck.

Nancy Hamilton
University of Northern Iowa
hamilton@uni.edu

---------------
From: "R. Seliktar"

This device is called Special Effect Generator.
R. Seliktar

---------------
From: knoek@sara.nl

Hi Neil,

Let's try again with respect to resolution. The video image consists of lines
; each line being an analog signal. IF you consider doing kinematic analysis
of this, i.e. digitizing of the video data, and the grid of the total image
is fixed, then clearly the resolution is going to get worse if you have to
reduce the size of each of the two original images by half to make them fit
onto one single image. Still not very nicely put, but I guess you get the idea.
If you are going to do visual analysis of the combined video images only,
however, I think it is unlikely that this resolution reduction is going to be
a problem.

Greetings from Holland,

Knoek van Soest

---------------
From: lichunwu@pioneer.arc.nasa.gov (Li-chun Wu SLN)

We have video splitter since September, 1991. We use it with two
Panosonic CCD cameras.


PELCO video screen splitter/inserter $297.00
VIDEOTEK VDA-16 video distribution amplifier (1 in and 6 out) $257.55

We got them through small business, I don't have the manufacturer's
address. The price was from 1991.

Addedum: Videotek's address is:
243 Shoemaker Road
Pottstown, PA 19464-6433
(800)800-5719
(215)327-2292
FAX (215)327-9295

li-chunwu@pioneer.arc.nasa.gov

---------------
From: Marcus Besser

From: Marcus Besser
Human Performance Laboratory
Thomas Jefferson University
Neil -

We have looked at buying a screen splitter, also - haven't bought it yet, so
this should not be considered a product endorsement. I know of two:

American Dynamics, 10 Corporate Drive, Orangeburg, NY 10962 phone: (914)
365-1000; FAX (914) 365-1007

Product is the AD1470A Splitter/Inserter.Price quoted to me by Jack Stein, of
Video Corporation of America (in New Jersey, USA, phone (908) 545-8000) was
$330 US.

Other product was:

PELCO, 300 West Pontiac Way, Clovis, CA 93612-5699 phone: (209) 292-1981; toll
free (if it works from Canada) 800-289-9100, 800-289-9150

Product is Model VSS100DT Screen Splitter/inserter Price quoted by Pro Video
(Broomall, Pennsylvania, USA, 215-328-7448, spoke to John Denest) was $393 US

Good luck. As I said, we were just getting prices - we haven't bought one, so
I don't know which is better.

I will also state that these are the simplest screen splitters available - not
a lot of adjustability, flexibility, etc.

Good luck!

Marc Besser
---------------
From: Jonathan Carmichael

This is an electric box for video cameras. From the explaination of your
needs I would think it is exactly what you are looking for. You can
contact Leitz dealers for information as they gave us our leads when
shopping around.
Take care, good luck searching, Jon

---------------
Sender: "HowieDBPG"

> Is it worse then just trying to make a video copy?

Neil: Unfortunately, it is much worse. What we have done is to plan ahead
when we want to dupe a specific tape. We use one camera at a time (possible
with my system) and then just show each view separately. Not the same
impact, but better than not seeing anything. I will send you the name of the
company on Monday.

Regards: Howard

---------------

From: Barry Munkasy

Although perhaps a little more than you need you might look into "Video
Mixers". These can be found in consumer and professional models and range
in price depending upon capablity. Mixers can be found in the US at any
store that sells VCRs and camcorders. Currently I use a consumer unit from
Panasonic. If you need additional info let me know.

Barry Munkasy
BMunkasy@Physics.usc.edu

---------------
From: Hakan Lanshammar

Dear Neil,

The "video splitter" function that you are asking about is called
a "wiper", and it is found as one of many functions on video mixers,
even on low cost mixers intended for the consumer market.
We are using mixers from Panasonic that cost about 1000 US dollars in Sweden.

Good luck
Haakan Lanshammar,
Systems and Control Group
Uppsala University
Sweden
hl@syscon.uu.se