Path: utzoo!mnetor!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!ames!pasteur!agate!eris!doug
From: doug@eris (Doug Merritt)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fixing flicker, & future frame rate issues
Message-ID: <8776@agate.BERKELEY.EDU>
Date: 15 Apr 88 19:31:04 GMT
References: <11157@ut-sally.UUCP> <8528@agate.BERKELEY.EDU> <11182@ut-sally.UUCP> <8577@agate.BERKELEY.EDU> <1367@hubcap.UUCP> <8649@agate.BERKELEY.EDU> <11227@ut-sally.UUCP> <8693@agate.BERKELEY.EDU> <11255@ut-sally.UUCP>
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Organization: University of California, Berkeley
Path: utzoo!mnetor!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!ames!pasteur!agate!eris!doug
From: doug@eris (Doug Merritt)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fixing flicker, & future frame rate issues
Message-ID: <8776@agate.BERKELEY.EDU>
Date: 15 Apr 88 19:31:04 GMT
References: <11157@ut-sally.UUCP> <8528@agate.BERKELEY.EDU> <11182@ut-sally.UUCP> <8577@agate.BERKELEY.EDU> <1367@hubcap.UUCP> <8649@agate.BERKELEY.EDU> <11227@ut-sally.UUCP> <8693@agate.BERKELEY.EDU> <11255@ut-sally.UUCP>
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Reply-To: doug@eris.UUCP (Doug Merritt)
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In article <11255@ut-sally.UUCP> bryan@gamera.cs.utexas.edu writes:
> -Flicker:  A perceived INTERMITTENCE in an ENTIRE image, as in successive
>  frames interleaved with intervals of 'darkness' (= absence of image).
> -Jerkiness:  A perceived DISCONTINUITY of motion, due to a slow frame  rate.
> -Double-shuttering addresses FLICKER, by equalizing the on and off
>  intervals for a frame.
> -Nothing but a higher frame rate or interpolation helps jerkiness.

I agree with all of this.
 
>	Jitter:  A perceived MOTION of an image COMPONENT due to PARTIAL
>	images being interleaved, as in interlaced displays.

I think "jitter" as defined here is an unnecessary term, since it only
results from buggy timing (software: synchronized to a 60hz rate rather
than 30; hardware: what fF does).

>	-flickerFixer should really be called jitterFixer.

Maybe, since it's got the bug necessary for your definition of jitter
above. This means that we use the term "jitter" just to describe buggy
hardware and/or software? Self-consistent, but I'm not sure it'll catch
on...there are a lot of people who use "jitter" and "flicker"
interchangeably. Perhaps rather than using a specialized meaning for
the word, we instead need to encourage fF (and anyone else with that bug)
to do things right.

	Doug Merritt		doug@mica.berkeley.edu (ucbvax!mica!doug)
			or	ucbvax!unisoft!certes!doug