eric@batcomputer.tn.cornell.edu (Eric Fielding) (04/15/89)
I have not seen a discussion of this lately, but I think it would still be best if people sent me mail, and I can post a summary. We are now in the market for a RGB video to NTSC (i.e. VCR) converter. It seems like this is a rapidly changing field, so the info I had from last year may not be valid. I have heard that it is much more difficult (i.e. expensive) to go from a 1024 or ~900 line RGB to NTSC than it is from a 512 line screen, because another box is needed to convert the scan frequency. Is this still true? Is there any point in trying to put 1024 lines on a VCR anyway? We will probably be using a 'regular' VCR to record and definitely want video that can be played on a 'regular' VCR. Thanks a lot. ++Eric Fielding fielding@geology.tn.cornell.edu eric@crnlthry.bitnet ...!cornell!batcomputer!eric (UUCP)
sparks@corpane.UUCP (John Sparks) (04/21/89)
In article <2441@helios.ee.lbl.gov>, johnston@lbl-csam.arpa (Bill Johnston [csr]) writes: > In article <7753@batcomputer.tn.cornell.edu> fielding@geology.tn.cornell.edu writes: > >We are now in the market for a RGB video to NTSC (i.e. VCR) converter. It > >seems like this is a rapidly changing field, so the info I had from last > >year may not be valid. > > [long message about expensive RGB encoders, time base correctors, and ] > [ Targa board as cheap alternative. ] > > Bill Johnston > (wejohnston@lbl.gov) Or he could just go out and buy an Amiga, and a genlock for about $1000. It is already NTSC compatable right from the box and there is a lot of good video software and hardware (such as frame grabbers, genlocks, and single frame VCR controllers). - -- John Sparks | {rutgers|uunet}!ukma!corpane!sparks | D.I.S.K. 24hrs 1200bps [not for RHF] | sparks@corpane.UUCP | 502/968-5401 thru -5406 The next sentence is true. The previous sentence is false.
mcdonald@uxe.cso.uiuc.edu (04/23/89)
> >We are now in the market for a RGB video to NTSC (i.e. VCR) converter. It > >seems like this is a rapidly changing field, so the info I had from last > >year may not be valid. It is very easy to program a VGA to get quite close close to NTSC scan rates. You, of course, lose BIOS mode switching support, so you have to write your own programs (or generate a TSR to trap an appropriate mode set call.) AS I recall, I got it to produce 240x640 (noninterlaced of course). I this works great for sending video to big screen TV's that are already set up for lectures, etc., as long as they take RGB (NTSC scan rate) or you get a modulator (OK, I made one from a chip, but you should be able to buy one.) Question is, does anybody make a genlock for the VGA? There is a line on the video connector for inputting the clock rate, but I see no answer for the non-interlace problem. What would happen if you recorded the output on a regular high-class home VCR, is it not possible to play these tapes on pro grade (i.e. very expensive, found only in TV stations) home format VCRs that feed out broadcast-grade sync? OR do TV stations, when they play consumer tapes, just play them on a regular VCR into a generic resynchronizer box (something that digitizes the frames and plays them out at the right rate)? Doug McDonald
steimle@unocss.UUCP (Scott A. Steimle) (04/24/89)
>> In article <7753@batcomputer.tn.cornell.edu> fielding@geology.tn.cornell.edu > writes: >> >We are now in the market for a RGB video to NTSC (i.e. VCR) converter. It >> >seems like this is a rapidly changing field, so the info I had from last >> >year may not be valid. I seemed to have missed any previous discussion of how this is done. I have an NEC television with RGB compatibility, video in/out, and a Zenith PC (Z-158). Athough I don't have a VCR yet, what should I look for in order to made things 'link up'? I've had ideas of doing the following things. Maybe someone out there can tell me whether or not they are feasible or possible (please). 1) Record, on my (not yet acquired) VCR, programs that I run on my PC. 2) Save to disk any frames from a VCR tape in some standard graphic format. 3) Save to disk a screen from my TV (no VCR involved). Thanks in advance. Scott. -- BITNET : steimle@unoma1 "Don't accept that what's happening, INTERNET : steimle@zeus.unl.edu is just a case of other's suffering - USENET : uunet!zeus.unl.edu!steimle or you'll find that you're joining in the turning away." - Pink Floyd -
dave@onfcanim.UUCP (Dave Martindale) (04/29/89)
>> It is possible to encode RGB >> signals whose source cannot be locked to external sync, but this can be >> expensive, > >This could alternatively be done using a sync generator that >accepts an external genlock signal. While it would be preferable >to have the sync generator be the master, this can give acceptable >results if the RGB source to which you are locking is sufficiently >stable. For really "broadcast quality" video, the colour subcarrier has to be locked in phase to sync. If you use the sync generator as a master, you automaticallly have this. If you use the framebuffer as the master, most sync generators will lock their sync to the framebuffer's, but let the subcarrier free-run, so that sync and subcarrier are unrelated. This is what 1/2 inch and 3/4 inch VCR's produce anyway, so it's good enough for many purposes, but is isn't fully "standard" NTSC.
brianm@sco.COM (Brian Moffet) (05/21/91)
I saw an add the other day for an RGB to NTSC/PAL converter. It claimed to
convert anywhere from 20-90 kHz to NTSC/PAL, S-Video, and Y,R-Y,B-Y
formats. The company putting this one out is called RGB Spectrum.
Would someone please comment on these boxes in general, how much they are,
and how well they work? I am thinking about putting together a system
and these sound rather interesting.
And yes, I am intimate with the Commodore Amiga. I know what it can/can't
do and its costs.
thanks very much
brian moffet
uunet!sco!brianm or brianm@sco.com
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brianm@sco.com Speaking for Myselfmark@calvin..westford.ccur.com (Mark Thompson) (05/22/91)
In article <U=A.674772722@sco> brianm@sco.COM (Brian Moffet) writes: >I saw an add the other day for an RGB to NTSC/PAL converter. It claimed to >convert anywhere from 20-90 kHz to NTSC/PAL, S-Video, and Y,R-Y,B-Y >formats. The company putting this one out is called RGB Spectrum. >Would someone please comment on these boxes in general, how much they are, >and how well they work? I am thinking about putting together a system >and these sound rather interesting. They are called video scan converters and are made by a few different manufacturers including RGB Spectrum, Folsom Research, and Lyon Lamb. All of them do a very good job at converting RGB to 15KHz video and cost in the $12K to $16K range. In the workstation realm, these are pretty much the devices you require to do video work unless your graphics board already specifically supports video. Ofcourse you already know that in the PC realm, an Amiga with a good quality genlock will be much more cost effective than something else + a scan converter. Contacts: (415) 848-0180 RGB Spectrum (916) 983-1500 Folsom Research I don't have a number handy for Lyon Lamb Hope this helps %~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~% % ` ' Mark Thompson CONCURRENT COMPUTER % % --==* RADIANT *==-- mark@westford.ccur.com Principal Graphics % % ' Image ` ...!uunet!masscomp!mark Hardware Architect % % Productions (508)392-2480 (603)424-1829 & General Nuisance % % % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~