From: nan@matt.ksu.ksu.edu (Nan Zou)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Interlace video (Was Re: PC (OS/2) / Amiga debate)
Date: 6 Sep 1992 05:14:54 -0500
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu

danaf@bray1b.its.rpi.edu (Frank R. Dana Jr.) writes:
>nan@matt.ksu.ksu.edu (Nan Zou) writes:

[...]
>>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.

>I said DISPLAYS, which was not the best choice of words. I should have used
>a word like "screens" or "monitors"... I meant interlaced monitors.

My point still stands.  Most VGA monitors will do at least 60 Hz non-
interlaced display.  You may be referring to some SVGA monitors, which can
not handle high resolutions without resorting to interlacing.  The NEC 3D
for example, is non-interlaced at 800x600 but interlaced at 1024x768,
simply because the monitor can't sync up to frequency that high, 48 kHz.

For me, I'd sooner drop down to lower resolution than looking at a
flickering high res interlaced display, I value my eyes too much.

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

>NOT TRUE! The Amiga is a machine targeted primarily toward the video market. 

Which part is not true?  It's bad on the eyes or...  If you think interlace
is just fine, why did you buy your flicker fixer?  You have too much money
to burn?  

As I said, I didn't mean to trivialize the importance of video or the Amiga's 
superiority in this area (or maybe I did).  I was talking about the quality 
of interlaced video in an objective manner.  So interlaced display may be
necessary for video work, it STILL looks worse on the eyes than a non-
interlaced one, OK?  You may not notice anything.  But accroding to studies
the mean at which people can detect flicker is around 65 Hz, with standard
deviation of around 5 Hz, this is a normal/Gaussian distribution, which
means half the people will notice flicker if the refresh is below 65 Hz.
All of the current PC video cards support at least 70 Hz or 72 Hz vertical
refresh, I run my ET4000 at 800x600 with 72 Hz refresh on my Sony Trinitron
monitor and the picture is rock solid.  The equivalent refresh rate in
interlaced mode will have to be 144 Hz, can your Amiga generate that high a
refresh?

>The fact that it has an interlaced display shows that focus. The display is
>certainly not "irrelevant"

It is irrelevant when I'm talking about picture quality.

So Amiga is tailored for the video market, this is a good thing.  But when
one's not doing any video work, the interlacing becomes a disadvantage.

>>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 see no problem. You really do get used to it. I owned an Amiga for over four
>years before I bought my flicker-fixer, and had no eye trouble. At one point,
>over a summer when I could not find a job, there were days when I would use
>the thing 10, 12 hours... up to 8 hours STRAIGHT. I'm still sighted.  9)

Each person will of course see things differently, but wouldn't you agree
the display looked BETTER after you put the flicker fixer in?

>>>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?

>Uhm... in the Amiga community? 10-20% professionally/semiprofessionally, and
>about 30-40% "fool around". (Okay, okay... I just made up those numbers. But
>we'll ask Dave Haynie, someone who should have the market research to prove it.
>Dave? How close was I? I may have even UNDERESTIMATED.)

As long as we are throwing around numbers, let's say 80% of the Amigas are
in Europe, and most of these are owned by gameplayers with a one floppy
A500, how likely do you think they are to "fool around" with video
production?

And EVEN if there's a large number of people doing video work, do you think
they bought their computers for nothing other than video?  At some point
they'll want to write a letter, call a BBS, is interlacing still beneficial
in these situations?

>>Believe me, the flicke4qring 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.

>AHA! Well, that's half of the problem, then. PAL video has its own flicker,
>especially when shoved onto an NTSC screen. Anytime I run my palbooter, I
>go half-crazy from that damn flashing screen. If you are looking at a PAL
>screen, you have a better chance of going blind from the PAL than from the
>interlacing!

I've also looked at an interlaced display on my own monitor, the flickering
especially with a bright background, can give me a spliting headache real
quick.

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

>So, then you jump down a video mode! What's the big deal? It's not like every
>display on the Amiga is interlaced. We get up to 724x482 (?) non-interlaced, 
>which is fine for 90% of the applications people want to run. 

Interlacing or non-interlacing doesn't tell the whole story, vertical
refresh rate is the ultimate factor.  Of course, interlaced refresh will
have to be twice that of non-interlaced to be equivalent.  So, what's the
refresh rate of that 724x482 screen?

-- Nan
Newsgroups: comp.sys.amiga.advocacy