From: skip@tacky.cs.olemiss.edu (Skip Sauls)
Subject: Re: Interlace video (Was Re: PC (OS/2) / Amiga debate)
Organization: University of Mississippi, Dept. of Computer Science
Date: Fri, 4 Sep 1992 22:09:56 GMT

In article <187t3iINNk58@matt.ksu.ksu.edu> nan@matt.ksu.ksu.edu (Nan Zou) writes:
>danaf@aix.rpi.edu (Frank R. Dana Jr.) writes:
>
>>I hate getting involved in these flame wars, but I have to make one point 
>>about the Amiga's video display. 
>
>><BTW: could be PLEASE cool off on the quoting? 4,5 levels is excessive...>
>
>>In his last message, Charles knocks the Amiga for having an interlaced video
>>display. No, Charles, this is NOT a sign of poor quality. First off, many 
>>real-world PC displays are interlaced. Just because YOURS isn't doesn't mean
>
>I think you're wrong on that one.  Standard VGA use 31.5 KHz horizontal
>syncing frequency and 60 Hz vertical non-interlaced refresh.  And I don't
>think EGA and CGA is interlaced either.

There are/were a couple of boards that supported CGA interlaced and it is
possible to promote some SVGA boards into interlaced modes.  

>But let's face it -- interlaced video is bad for the eyes, the fact that it
>facilitates video work is irrelevant.

8 point text on a high-contrast interlaced screen may be bad on the eyes,
but billions of people are exposed to interlaced screens daily and don't
seem to have any problems with it.  If you are doing any sort of work 
for broadcast, interlaced video most certainly is relevant.

>>nobody in the PC market had ever heard of interlacing. Secondly, the fact 
>>that 
>
>Some video cards do have interlaced video modes, mostly at high resolution
>like 1024x768, but they look so bad no one uses them.

No one?  I beg to differ as I use that mode on a daily basis.  Windows is
a complete screen hog and it takes at least that resolution to create a
usable working environment.  Of course we all know that real GUIs support
the seamless use of multiple screens...  :-)

>>Commodore included interlacing on their display simply indicates the 
>>different focus of the Amiga line - toward video. ALL vieo displays, 
>>including the one on every TV in your house, is interlaced. There's 
>>nothing WRONG with interlacing, 
>
>No, there's nothing wrong with a interlaced display -- unless you have to
>look at it in close range for long periods of time, then there's a problem.

I spent many hours in front of a TV at close range as a child and used
interlaced video on an Amiga for 5 years, yet I have perfect uncorrected
vision.  Where is the problem?  I'm not trying to say that I like the
flicker, but I don't believe that it is some sort of threat to one's health.

>>and it is NOT a "low-end" alternative to a steady display. It has MANY, MANY
>>applications in the real world, at levels the IBM machines cannot touch. 
>
>Yes, the video aspect, but how many use their computers for video?

Not many, but that is not because they don't want to, it is because they
cannot.  By the number of flicker-inducer boards for the Mac and PC, I'd
guess that there is quite a demand for computers which can be used for video.

>>Furthermore, nobody has ever "gone blind" (literally or figuratively) from
>>looking at an interlaced screen. After a couple of days using one, you 
>>hardly notice it at all. Looking at ANY computer screen, especially one on 
>>which there
>
>Believe me, the flickering is very noticable, I've looked at an interlaced
>PAL display and I will go blind if I have to look at it for long periods of
>time.

If you looked at the PAL display in North America, much of the flicker is
due to the 50Hz screen vs the 60Hz lighting.

>Idealy, interlaced video mode should only be used when doing video work,
>all other times it'll just put unnecessary strains on the eyes.

You may be right, but please remember that many of the folks here are
doing video work most of the time and non-interlaced video is simply
not acceptable.  If these folks wanted to use spreadsheets, word processors,
and other such boring things, they'd get a Clone.

>-- Nan

Skip Sauls
skip@tacky.cs.olemiss.edu



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