arritt@kuhub.cc.ukans.edu (11/03/90)
Here's our situation: We have a SGI 4D/25, are buying a 4D/35, and want to
be able to make videotapes of results from our numerical models. We
ordered something called a "genlock" board with the 4D/35 because we were
told we would need it to dump the screen to a VCR.
Once we get our hardware set up, what kind of software do we need?
Do we need a special animation package to make it all work?
The main problem is that we're theorists who don't really know much at
all about the nuts-and-bolts of programming in general or the graphics
business in particular, but DO understand that thoughtful
graphics can significantly clarify the display of scientific data.
We have managed to turn enormous files of floating-point numbers into
"still" pictures, and now want to string a lot of these together to
show how our solutions evolve in time. Currently one of us (me) is using
NCAR Graphics 3.0 and the other is using some stuff from NCSA.
What we'd like to do is to keep using the same graphics programs we're
using now to generate "stills", and dump the data a frame-at-a-time
to a VCR. (Fortunately we need to make only fairly short
movies, maybe a minute or so at a time.) If we have to use
a special graphics program, we'd need to either (1) recode all of our
stuff ourselves, and like I said, we're theorists rather than programmers
(i.e. it'd take us forever, IF we could get it to work at all); or (2) hire a
programmer (actually we'd like to hire a programmer anyway, but can't get
the $$$ given the current environment for research funding).
Can it be done? We have a *little* money left over for hardware/software;
will we need a special frame-advance VCR? Any advice you can offer -- even
"give up, it'll never work", with reasons why -- would be appreciated.
________________________________________________________________________
Raymond W. Arritt |
Assistant Professor |
Dept. of Physics and Astronomy | "everyone knew that as time went
Univ. of Kansas | by they'd get a little bit older
Lawrence, KS 66045 | and a little bit slower..."
arritt@kuhub.cc.ukans.edu |
arritt@ukanvax.bitnet |
drb@eecg.toronto.edu (David R. Blythe) (11/03/90)
In article <26471.27318f0c@kuhub.cc.ukans.edu> arritt@kuhub.cc.ukans.edu writes: >Here's our situation: We have a SGI 4D/25, are buying a 4D/35, and want to >be able to make videotapes of results from our numerical models. We >ordered something called a "genlock" board with the 4D/35 because we were >told we would need it to dump the screen to a VCR. >Once we get our hardware set up, what kind of software do we need? >Do we need a special animation package to make it all work? > > >What we'd like to do is to keep using the same graphics programs we're >using now to generate "stills", and dump the data a frame-at-a-time >to a VCR. (Fortunately we need to make only fairly short >movies, maybe a minute or so at a time.) If we have to use >a special graphics program, we'd need to either (1) recode all of our >stuff ourselves, and like I said, we're theorists rather than programmers >(i.e. it'd take us forever, IF we could get it to work at all); or (2) hire a >programmer (actually we'd like to hire a programmer anyway, but can't get >the $$$ given the current environment for research funding). > First, the genlock card serves two functions: it produces composite video suitable for recording on a north american vcr (NTSC). Second, it provides the ability to synchronize the iris video signal with a sync signal provided by a external source. This is used to produce a very stable video signal while recording. To make use of the board look at the example code in 4Dgifts/examples/video for setting up the board. Note that the image size will be reduced to the 646x485 pixel region in the lower left hand portion of the screen rather than the normal 1280x1024. (i.e. the constants XMAX170 and YMAX170 in <gl/gl.h> can be used to set up the window.) You can record directly from the iris by putting it into NTSC mode and connecting the composite ouput cable from the cg2 (genlock) board to your vcr. However, this set-up will only allow you to record in real-time not frame at a time. So if you can't display your images fast enough you lose. You will invariably have pauses and other interference from other programs running on the system, etc so this technique is only useful for making quick and dirty videos or demonstration videos where you are going to interact with the program. It also helps if you have lots of memory to hold the images in memory for rapid sequencing through them. For an example of that, look at the program 4Dgifts/iristools/imgtools/movie. If you record frame at a time, then you need fancier equipment. First of all you need a vcr which is capable of doing frame acurate recording. This is usual done on the vcr as an insert edit. Second the vcr needs to be remotely controlled and you need something to do the actual control (an animation controller). The vcr also should be kind of heavy-duty or you will wear it out pretty quick. Such a vcr usually has glass heads, among other things. We (and many other places) use a Sony BVU-950 3/4" u-matic vcr. It costs about $17K canadian and is ``industrial quality'' i.e. better than home use (+ or - some caveats) but not broadcast quality. Other (cheaper) possibilities include various S-VHS vcrs from JVC, etc. I am not too up on the part of the equipment range. Best of all would be the Sony LVR-5000 video disk recorder for about $25K US, which can record very very fast relative to tape and very high quality (i.e. broadcast quality). Tape machines have to do a 5-second preroll to make sure everything is up to speed and in sync before recording so it takes ~10 seconds to record each image :-(. The animation controller is the intermediary between the workstation software and the vcr and is used to position the tape, tell the vcr when to record, etc. Diaquest, Lyon Lamb, and Videomedia make pretty reasonable stuff (we have a Lyon-Lamb Mini Vas which is pretty commonly used). Finally you need the software to display images and talk to the animation controller. This is the cheapest part. You can get a copy of gplot from the pittsburgh super computer centre (ftp from calpe.psc.edu) which can display NCAR cgm files on a number of machines and has a driver for a diaquest animation controller and sony video disk recorder. (Last I looked though the sgi gl display driver still needed some work). I believe minivas drivers are also available although I forget from where (we have one which we have never distributed to anyone before). I think some of the NCSA tools have hooks in them for video recording (at least they can display in NTSC sized windows in near real time for some data sets). It probably wouldn't take much to add drivers for frame at a time. The tough part is converting your data into their annoying HDF format. Unfortunately, I think you are still going to have to spend a few more $$ for additional equipment and find someone with a modest understanding of video to help you get it set up. Hope this helps you out. david blythe ontario centre for large scale computation drb@clsc.utoronto.edu
pepke@gw.scri.fsu.edu (Eric Pepke) (11/06/90)
In article <1990Nov2.185517.24899@jarvis.csri.toronto.edu> drb@eecg.toronto.edu (David R. Blythe) writes: > Best of all would be the Sony LVR-5000 video disk recorder for about > $25K US, which can record very very fast relative to tape and very high quality > (i.e. broadcast quality). We have one of these. It works great. It also obviates the need for the genlock board, as it can take RGBS inputs at RS-170A timings as well as NTSC and composite video. The internal RGB to NTSC converter works quite well. It's also pretty easy to program over an RS-232 wire. It's about $23K list. With educational discount and bid incentive you should be able to get it for well under $20K. Still expensive, but worth it. Eric Pepke INTERNET: pepke@gw.scri.fsu.edu Supercomputer Computations Research Institute MFENET: pepke@fsu Florida State University SPAN: scri::pepke Tallahassee, FL 32306-4052 BITNET: pepke@fsu Disclaimer: My employers seldom even LISTEN to my opinions. Meta-disclaimer: Any society that needs disclaimers has too many lawyers.
pepke@gw.scri.fsu.edu (Eric Pepke) (11/08/90)
In article <1346@sun13.scri.fsu.edu> I write: > It also obviates the need for the > genlock board, as it can take RGBS inputs at RS-170A timings as well as > NTSC and composite video. My apologies for this blatant bogosity. I meant to write "component video." It was merely a typo and had nothing to do with my membership in the Organization for Redundancy and Duplication Club. Eric Pepke INTERNET: pepke@gw.scri.fsu.edu Supercomputer Computations Research Institute MFENET: pepke@fsu Florida State University SPAN: scri::pepke Tallahassee, FL 32306-4052 BITNET: pepke@fsu Disclaimer: My employers seldom even LISTEN to my opinions. Meta-disclaimer: Any society that needs disclaimers has too many lawyers.