Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!unisoft!gethen!farren
From: farren@gethen.UUCP (Michael J. Farren)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fixing flicker, & future frame rate issues
Message-ID: <890@gethen.UUCP>
Date: 22 Apr 88 09:09:57 GMT
References: <11157@ut-sally.UUCP> <8528@agate.BERKELEY.EDU> <11182@ut-sally.UUCP> <869@gethen.UUCP> <2988@leo.UUCP>
Reply-To: farren@gethen.UUCP (Michael J. Farren)
Organization: There's Unix there in Oakland
Lines: 39

In article <2988@leo.UUCP> harald@leo.UUCP ( Harald Milne) writes:
>In article <869@gethen.UUCP>, farren@gethen.UUCP (Michael J. Farren) writes:
>> This is not what happens at all.  Non-interlaced mode does NOT have
>> "lines without information", and alternate half-frames are NOT absent.
>
>	I was responding in the context of the original posting.

Well, I don't care about that context a whit - the statement that there
is "information missing" in non-interlaced mode is flat incorrect, 
regardless of context.  While it might be hidden, it is NOT missing.

Let me put this another way:  in interlaced mode, you are trading off
the ability to update the display 60 times per second for the ability
to put more lines on the screen.  There are 60 fields worth of information
sent to the monitor each second, in either mode, and no information is
lost.  Alternate half-frames are not lost, they are simply displayed in
the same space as the other half-frames.

>	If you don't believe me, record Amiga video in Interlace and
>Non-Interlace.  Interlace will look fine, where Non-Interlace will look like
>sh*t. There is information absent.

No.  There is NO INFORMATION ABSENT, except for one bit - the slight
difference in timing between even and odd fields.  Vertical sync timing
differs between the two, and that is the ONLY difference.  Perhaps some 
VCRs require the timing change, but the funny thing is that my own recordings
of non-interlaced displays on a cheapo VCR look just fine.  Maybe Beta
VCR's just can't hack it :-)

>Video displays can get terribly confusing.

Yes, they can.  I've found this out by working with them for almost
fifteen years now, including several years designing them.  Don't try
and teach your grandma to suck eggs, eh?

-- 
Michael J. Farren             | "INVESTIGATE your point of view, don't just 
{ucbvax, uunet, hoptoad}!     | dogmatize it!  Reflect on it and re-evaluate
        unisoft!gethen!farren | it.  You may want to change your mind someday."
gethen!farren@lll-winken.llnl.gov ----- Tom Reingold, from alt.flame