stever@videovax.UUCP (02/19/87)
In article <1235@husc6.UUCP>, Justin J. M. Grunau (grunau_b@husc4.UUCP) writes: > Forgive my ignorance, but all this recent discussion about the Amiga's NTSC > standard has got me confused. . . . > But this confuses me -- I understand that NTSC standards will not allow a > 640 by 400 non-interlaced display; but I thought the Amiga was famous for > having not only NTSC output, but also digital and analog RGB, which are, > unless I am confused, NOT NTSC-compatible. Could somebody enlighten me on > the distinction? NTSC is an acronym commonly used to refer to the National Television System Committee's report #7, and the color transmission standard it specifies. By reference, it includes the previous monochrome (black-and- white) system standard, though with slight modifications. Thus, an NTSC signal is 29.97 frames/second (usually called 30 frames/sec) with 2:1 interlace (which means 59.94 fields/second). The color subcarrier is 3.579545 MHz. The RGB output of the Amiga, while not directly NTSC-compatible, has the same timing as the NTSC output. (If this were not the case, it would be necessary to have two sets of video output generation circuitry, and at least twice as many display ram accesses for each pixel.) The RGB output signal can be directly converted to NTSC (though with some loss of resolution, because the bandwidth of an NTSC signal is not adequate for medium- to high-resolution images). A point that should be made: as the resolution and the line rate of the display are increased, there is a dramatic increase in both the amount of display RAM required to contain an image, and the bandwidth of the channel from memory to the display. If the display is interlaced, the output data rate is half that required for a progressively-scanned display. Doubling the display data rate of the present Amiga would be an expensive undertaking, probably moving the Amiga out of the consumer price range. Steve Rice ---------------------------------------------------------------------------- {decvax | hplabs | ihnp4 | uw-beaver}!tektronix!videovax!stever
hand@ece-csc.UUCP (02/25/87)
In article <4237@videovax.Tek.COM> stever@videovax.Tek.COM (Steven E. Rice, P.E.) writes: >In article <1235@husc6.UUCP>, Justin J. M. Grunau (grunau_b@husc4.UUCP) >writes: > >> Forgive my ignorance, but all this recent discussion about the Amiga's NTSC >> standard has got me confused. . . . > >> But this confuses me -- I understand that NTSC standards will not allow a >> 640 by 400 non-interlaced display [...] I really want a 640 by 400 non-interlaced display, especially for fancy fonts and word processing like the Mac. Then, if you wanted to be NTSC-compatible, just turn on the interlace. As things stand now, the Amiga is marginally usable for WYSIWYG and desktop publishing. If bandwidth is the problem, I'd be happy with just one bit plane, but let's have HIGH RESOLUTION TEXT WITHOUT THE JITTERS! Steve Hand decvax!mcnc!ece-csc!hand Box 7911 ECE Department NC State Univ. (919) 737-2336 ext. 34 Raleigh, NC 27695 (919) 834-4375
hatcher@INGRES.BERKELEY.EDU.UUCP (02/26/87)
In article <3250@ece-csc.UUCP> hand@ece-csc.UUCP (Steven Hand) writes: > [...] If bandwidth is the problem, I'd >be happy with just one bit plane, but let's have HIGH RESOLUTION TEXT WITHOUT >THE JITTERS! Settle down; there's no reason to get antsy. There are several problems with supporting 640 x 400 noninterlaced, but the digital half of it is relatively easy. The biggest problem is that monitors that can do this cost about $2000 by themselves. Thus very little of the Amiga audience could afford even the monitor, let alone monitor plus more expensive graphics circuitry. This adds up to saying "Hey, it's not Commodores fault...it's just that such technology is expensive. Price a color Sun workstation, for instance". But good news is at hand. Higher resolution add on graphics boards will be released for the Amiga 2000. How easy it'll be to adapt this for our 1000 is an open question. Even better news: by the end of the year, there will be high end television sets that'll be able to display images without interlace by using a frame buffer. So you'll be able to just buy a tv and use it with your existing Amiga 1000. It'll still be pricy, of course, but if you really want it... This sort of thing is unavoidable. Eventually, the horsepower of a Cray will be available in an affordable home computer. But by then, that'll seem real slow. Same thing holds for display technology. There will always be high-end technology, which will always A) be desirable to those with low budgets, and B) will be expensive relative to low budgets. The only problem with the Amiga is that it gives us *almost* super graphics at low end prices. This is not *really* a problem, except that it whets your appetite for super graphics without the compromises like interlace. Doug
cmcmanis@sun.UUCP (02/26/87)
In article <8702260150.AA24233@ingres>, Doug Merritt writes: > Settle down; there's no reason to get antsy. There are several > problems with supporting 640 x 400 noninterlaced, but the digital > half of it is relatively easy. The biggest problem is that monitors that > can do this cost about $2000 by themselves. Thus very little of the Amiga > audience could afford even the monitor, let alone monitor plus more > expensive graphics circuitry. Ok, enough of this misinformation. Color 640 X 480 non-interlaced monitors cost about $600 (this is the NEC multisync), high persistance phosphor monitors cost about $1k (except for the new Amiga monitor which is $500). To effectively de-interlace the display you need a frame buffer and A/d and d/a chips and some clock circuitry. Building one is on my list of projects. I expect it to cost about $150. > This adds up to saying "Hey, it's not Commodores fault...it's just that > such technology is expensive. Price a color Sun workstation, for instance". A Sun has a resolution of 1152 X 900 pixels, those monitors cost some serious bucks. -- --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.
hutch@sdcsvax.UUCP (02/27/87)
<>
Strangely there is little to prevent you from having multiple
resolutions out of a single frame buffer, but it is expensive.
The frame buffer I work on daily has a range of resolutions from
1526x1152 non-interlaced to 1024x512 NTSC (remember NTSC is
analog!) to 512x512 NTSC. If you want to service them all at
once, no. Changing the scan rate eats up valuable resources.
Huh, you say? Yes, the vertical blanking interval is a time of
great fun and speed. If you shorten it, certain operations will
slow down. does the blitter use the vertical blanking interval?
Or does it sneak into the horizontal flyback to/instead (now that
would be a neat trick) ? It can be done, but is expensive. Not
just larger memory, but faster clocks, and it is then turning into
too much money for me to pay. Money, yep, that is what it boils
down to (atleast for me).
-
--
Jim Hutchison UUCP: {dcdwest,ucbvax}!sdcsvax!hutch
ARPA: Hutch@sdcsvax.ucsd.edu
Never seems to be enough resolution, memory, or speed, now why is that?eve@ssc-vax.UUCP (02/27/87)
In article <8702260150.AA24233@ingres.Berkeley.EDU>, hatcher@INGRES.BERKELEY.EDU (Doug Merritt) writes: > Settle down; there's no reason to get antsy. There are several > problems with supporting 640 x 400 noninterlaced, but the digital > half of it is relatively easy. The biggest problem is that monitors that > can do this cost about $2000 by themselves. Thus very little of the Amiga > audience could afford even the monitor, let alone monitor plus more > expensive graphics circuitry. Correct me if I'm wrong, but the NEC Multisynch monitor can handle 640x400 noninterlaced, analog RGB and is available for $500 mail order. I would much prefer one of these to a long persistence (smear) monitor. There are several other manufacturers introducing comparable monitors at similar prices. -- Mike Eve Boeing Aerospace, Seattle ...uw-beaver!ssc-vax!ssc-bee!eve ATTN CIA: cryptography stealth mx laser hmb
spierce@crash.UUCP (03/01/87)
The NEC Multisync can handle 800 x 560 non-interlaced, but not with an Amiga driving it. I believe he meant that a monitor using digital framestore to create a non-interlaced picture costs about $2000 (such as the Toshiba CZ-2697).
chapman@fornax.uucp (John Chapman) (03/09/87)
> In article <8702260150.AA24233@ingres>, Doug Merritt writes: > > > Settle down; there's no reason to get antsy. There are several > > problems with supporting 640 x 400 noninterlaced, but the digital > > half of it is relatively easy. The biggest problem is that monitors that > > can do this cost about $2000 by themselves. Thus very little of the Amiga > > audience could afford even the monitor, let alone monitor plus more > > expensive graphics circuitry. > > Ok, enough of this misinformation. Color 640 X 480 non-interlaced monitors > cost about $600 (this is the NEC multisync), high persistance phosphor > monitors cost about $1k (except for the new Amiga monitor which is $500). > To effectively de-interlace the display you need a frame buffer and > A/d and d/a chips and some clock circuitry. Building one is on my list > of projects. I expect it to cost about $150. If you can get three multi-bit d/a's with the necessary speed and linearity for $150 I would like to hear where; something with at least 4 but preferably 6-8 bits/channel . . > -- > --Chuck McManis > uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com > These opinions are my own and no one elses, but you knew that didn't you. *** REPLACE THIS LINE WITH YOUR MESSA J J