[stella] Flickering on LCDs

[seagtgruff at aol.com]

Well, it makes sense to me that the lines are thinner, because it's a 1080p HDTV-- more than twice as many lines as an interlaced 525-line image-- but I know almost nothing about how LCD TVs work, as compared to a liitle bit about how CRT TVs work. Yet it does seem odd to me that a standard 262-line Atari game screen looks solid, with no apparent gaps between scan lines, whereas a 262-line flickering Venetian blinds display shows gaps, and the lines for each frame are vertically offset from each other a little bit, as follows:

--------________--------________
--------________--------________
--------________--------________
etc.

I mean, the lines on each frame should be aligned together, shouldn't they? I could understand it if I was generating a 262,5-line interlaced screen, but it's just two 262-line screens flickered together. This is interesting; I'll have to start reading up on LCDs, HDTV signals, etc.

Michael


-----Original Message-----
From: Thomas Jentzsch <tjentzsch at web.de>
To: Atari 2600 programming list <stella at atari2600.org>
Sent: Tue, 15 Apr 2008 2:40 am
Subject: Re: [stella] Flickering on LCDs



Michael wrote:
Okay, I just played E.T. Book Cart on my HDTV, and it was definitely different. 
For one thing, there is no apparent flickering-- the two frames are blended 
together without the annoying, seizure-inducing flashing that I got on my old 
SDTV. That's actually very cool. However, the lines on the second frame are 
slightly-but-noticeably lower than the lines on the first frame, and the overall 
blended picture has definite blank lines between the lines of color (from the 
Venetian blinds). The Tron Man Picture Cart-- which uses Andrew's 3-frame RGB 
technique-- looks pretty darn good, too, although some flickering is noticeable. 
I'll have to try out a 262.5-line interlaced display on it one of these days.

I suppose that's coming from the varrious picture optimizations build into 
modern LCDs.

Actually you should be lucky if it works out fine, because I am pretty sure, 
nobody tests those optimizing algorithms with ancient hardware.

Have?fun!
Thomas
_______________________________________________________
Thomas?Jentzsch?????????|?***?Every?bit?is?sacred?!?***
tjentzsch?at?web?dot?de?|



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