piety@hplabsb.UUCP (Bob Piety) (07/01/87)
How can graphics images from, say, an HP SRX system or an EGA be converted to television video? That is, suppose I want to record my graphics on video tape-- how can I do that? Pointing a camera at the screen is quite lousy and has interference bars running through the picture. Has anyone done this? How? Thanks in advance. Bob
ugpoltr1@sunybcs.uucp (Jim Poltrone) (07/02/87)
As quoted from article <4198@hplabsb.UUCP> by Bob Piety: >How can graphics images from, say, an HP SRX system or an EGA be converted >to television video? That is, suppose I want to record my graphics on >video tape-- how can I do that? Pointing a camera at the screen is quite >lousy and has interference bars running through the picture. Agreed. Camera copies are usually inferior to what can be achieved "directly", i.e. with patch cords and the like. (But we all know this.) Unfortunately, this is the only thing that can be done if there is no suitable output jacks. >Has anyone done this? How? Well, I have no experience with either system. Do both output PAL code? (In other words, are you looking for PAL->NTSC or NTSC->PAL ? I believe you're looking for the former, especially with the EGA unit.) Here's what I would do: If the unit doesn't have it's own VCR, the first thing to do is to get it onto a PAL tape. Two ways to do this: 1) Fly to England and purchase a PAL VCR there. Naturally, this isn't feasible if one can't get the time off of work. Nor would it be the right thing to do if Customs imposed a high duty on electronic equipment. 2) Purchase a switchable-standard VCR here, and use it as a dedicated system -- set the standard to PAL and use it for recording only. Since the consumer demand for this is relatively low, you may have to order it from a specialty video catalog, or pay a premium price for it. A rental place may have such a unit, but I would doubt it. The next step is to convert the tape to NTSC. Here there are several options, although a few might be rather costly: a) Purchase your own standards converter. These units are usually sold in pairs (two one-way converters). I'd only consider this option if I was doing a fair amount of converting, as this option is quite expensive. b) Take the tape (and a blank one) to a professional studio that has a standards converter. But studio time is rather expensive -- I've heard rates ranging from $50 to $300. c) I know someone in Florida who has a PAL->NTSC converter. Send me e-mail and I will send you his address. If I was in your situation, I'd choose options 2 and c. If you plan on making several recordings, purchase the VCR; if not, rent it -- if you can find it. -- ____ ^ ____ |_ _|/ \|_ _| Jim Poltrone (a/k/a Poltr1, \ \/ \/ / the Last of the Raster Blasters) \/ ^ \/ / / \ \ uucp: [decvax,watmath,rocksvax]!sunybcs!ugpoltr1 / /___\ \ ARPAnet: ugpoltr1%buffalo@CSNET-RELAY /___________\ csnet: ugpoltr1@BUFFALO _/ /_ _\ \_ BITNET: ACSGJJP@SUNYABVA, UGPOLTR1@SUNYBCS |_____| |_____|
brown@nicmad.UUCP (Mr. Video) (07/02/87)
In article <4198@hplabsb.UUCP> piety@hplabsb.UUCP (Bob Piety) writes:
<How can graphics images from, say, an HP SRX system or an EGA be converted
<to television video? That is, suppose I want to record my graphics on
<video tape-- how can I do that? Pointing a camera at the screen is quite
<lousy and has interference bars running through the picture.
The only NTSC compatible signal is from the PC's CGA board. The other graphics
boards have higer frequency rates that are not recordable, or viewable,
directly on NTSC equipment. It is kind of like wanting to watch a PAL tv
picture on NTSC equipment. It MUST go through a standards converter. You
will need to find someone who has an EGA RGB to NTSC composite video converter.
You will NOT have the same quality on your NTSC recording that you have on the
EGA monitor.
--
harvard-\ ihnp4--\
Mr. Video seismo!uwvax.......!nicmad!brown
rutgers-/ decvax--/
terminus-/sparks@batcomputer.tn.cornell.edu (Steve Gaarder) (07/02/87)
There are two poroblems with recording most computer output: color encoding
and scan rates. The NTSC and PAL video standards have far poorer color
resolution than most computer graphics displays, so RGB video, where each
primary color has its own line, is used. RGB can be converted to NTSC with
an encoder, but most of your resolution goes away. For example, 80 column
text becomes unreadable, though 40 column is usually OK.
The other problem is that computer graphics display designers usually use
a horizontal scan rate greater than NTSC's 15.75 kHz, giving more scan lines
without flicker problems. Converting video at one scan rate to another
is a bear of a job, requiring lots of expensive gear.
The best way to get tapeable graphics is to use a Commodore Amiga, which
has very good graphics (for its class) and produces an NTSC composite
output. The IBM Color/Graphics adapter and the Tandy Color Computer 3
also have a composite output, but are
not as good as the Amiga in terms of number of colors and graphics
performance. I don't know about the Atari ST.
--
Steve Gaarder
Cornell University, 171 Hollister, Ithaca NY 14853 607-255-5389
UUCP: {cmcl2,decvax,rochester,uw-beaver,ihnp4}!cornell!batcomputer!sparks
BITNET: sparks@crnlthry.BITNET ARPA: sparks@tcgould.tn.cornell.edujon@oddhack.caltech.edu (Jon Leech) (07/03/87)
Summary: Expires: Sender: Followup-To: Distribution: In article <4198@hplabsb.UUCP> piety@hplabsb.UUCP (Bob Piety) writes: >How can graphics images from, say, an HP SRX system or an EGA be converted >to television video? That is, suppose I want to record my graphics on >video tape-- how can I do that? Pointing a camera at the screen is quite We render on the SRX, then filter the images to lower resolution and transfer to a frame buffer with NTSC & genlock. Our HP salesman told me yesterday that a version of the 98720 display with NTSC capability might be coming along early next year. -- Jon Leech (jon@csvax.caltech.edu || ...seismo!cit-vax!jon) Caltech Computer Science Graphics Group __@/ ``There is only one spacefaring nation today. And it's not the United States, comrade!''