Scrolling Text and LCDs

neilmcl

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I don't know whether the following phenomenom is common to most LCDs or my Sharp LC37P50E in particular. I've seen on programmes that output fast moving horizontal scrolling text, not the normal scrolling speed you see on News 24 etc, that often the text seems to lose integrity and sort of shimmers/breaks up so that it becomes virtually unreadable. This tends to happen specifically when the background image is moving. For example, the end credits on the now finished Jack Dee at the Apollo series.

Does it happen because the panel is trying to deinterlace the main background screen image but can't also cope with the fast scrolling text at the same time.

Any ideas?
 
neilmcl said:
Does it happen because the panel is trying to deinterlace the main background screen image but can't also cope with the fast scrolling text at the same time.

Any ideas?

I think you've hit the nail on the head there. My Hitachi 32ld7200 does a similar thing with fast moving credits, but only if there's lots of other stuff on screen at the same time.

Most of the time text is crisp and clear, but on super-fast credits you can see the text switching between 'crisp' and 'jaggy-interlaced'.

I've never seen it on anything other than credits, and even then, I only see it on credits that are moving too fast for me to read anyway! Doesn't bother me really- when the credits are rolling I'm usually walking toward the fridge for the a beer! :D
 
I posted an example of this about a year back and also a poll maybe 6 months ago. The general consensus was that it was to do with deinterlacing - no mention was made about other bits of the screen moving. The closing credits of Ballamory was used as an example and if you have kids you will know what I mean. Interestingly it seemed to affect the common screen based technologies - 100Hz CRT's, plasmas and LCD's. I think I had one post that said his screen was totally crisp - a Philips 9986 by cross referencing his username against his postings. Oddly, I had seen this behaviour on this Philips too so maybe it was a settings thing.
 
I thought this was partly a response issue?

The only reason I say that is because GaryB made mention of a new JVC due shortly with a super fast response driver that includes a split screen demonstration mode of scrolling text using a before / after scenario.
 
It's the deinterlacing. A high end set with Motion adaptive or motion compensated deinterlacing will handle it and render a nice image.

It's absolutely nothing to do with the lcd panel response time, although the LCD motion blur will make it look worse.

Incidentally, the effect occurs on any other moving object, it's just that the eye and brain seems to be particularly sensitive to the text.
 
I've noticed the same thing on my Sharp 32" P50. Good to know it's perfectly normal.
 

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