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General discussion

Projector Scaling & Maximum Resolution

Sep 26, 2005 12:06AM PDT

I'm looking at this projector: JVC DLA-SX21U http://www.projectorcentral.com/JVC-DLA-SX21U.htm

Its native resolution is: 1400x1050 Pixels

Its maximum resolution is: 1600x1200 Pixels

If maximum resolution is the highest input it can accept and scale down to 1400x1050, then how can it be compatible with 1920x1080 HDTV?

Discussion is locked

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Projector Scaling & Maximum Resolution
Sep 26, 2005 5:53AM PDT

Since this an older model that is no longer produced, I assume you are asking a general question.
Ditital TV,Projctors,etc all have a maximum native resoultion that they display.
Compatiably means that will scan convert other resoultions to thier native resoultion.
Here is a link that has a lot of info. John
http://www.cnet.com/4520-7874_1-5102926-1.html?tag=promo2

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heh...
Sep 26, 2005 9:12AM PDT

I assume by 1920x1080 you are talking about 1080i, well 1080i isn't exactly 1920 * 1080 pixels each field (60 fields per second), its an interlaced signal, so half comes on an odd field and the other half comes on an even field. can't compare interlaced signals with digital ones. there is a lot of other stuff going on with the de-interlacing & scaling.

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Other stuff?
Sep 26, 2005 9:23AM PDT

You're right, 1080i is only 540 lines at a time, but it is still a digital signal.

What do you mean 'other stuff going on' ?

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Wait....
Sep 26, 2005 9:29AM PDT

Are you saying since interlaced 1080i is only coming in at 540 lines at a time, that it is actually under the 1600x1200 limit?

I could be confusing lines & pixels again.....

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Projector Central Article
Sep 26, 2005 9:16AM PDT

Are you saying maximum resolution is the native resolution?

According to this article:
http://www.projectorcentral.com/maximum_resolution.htm

It says 'Maximum resolution is the highest resolution signal that the projector has been programmed to process and display.'

So if that's true, how can a projector with a maximum 1600x1200 resolution also say it is compatible with 1080i? If it can only process and display a resolution of 1600x1200 then it should not know what to do with 1920x1080.

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heh...
Sep 26, 2005 10:24AM PDT

because 1600x1200 progressive has a higher pixel count per second than a 1080i signal, its considered the maximum resolution of the two. as far as "other stuff" going on... a lot of it is proprietary & I haven't researched the inner workings of the faroudja or TI dark chips... or any other legacy chips before them, but the basics of converting an interlaced signal into a progressive signal might go something like this...

receive field A
scale the H/V down/up to meet native screen size
de-interlace with previously received & scaled field B
DISPLAY

or perhaps...
receive field A
deinterlace with previously received field B
THEN scale down result to native screen size
DISPLAY

FYI - that de-interlacing step can be very simple (& bad looking) or very complicated an smooth looking. sometimes its a trade off... too smooth versus too sharp (or jaggy).

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So....
Sep 26, 2005 11:41AM PDT

If I understand you correctly, a 1600x1200 progressive resolution is actually higher resolution than a 1920x1080 interlaced display. There for, a projector with a maximum resolution of 1600x1200 can accept 1080i because it is actually 540 lines at any given time?

Yes?

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This could also mean that.....
Sep 26, 2005 11:56AM PDT

A 1280x720 720p projector could convert an interlaced 1080i signal into a 960x540 progressive display that looks just as good as 1080i, providing that nothing is lost in the scaling phase.

But I guess something is always lost during scaling.

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kinda...
Sep 26, 2005 2:54PM PDT

you kinda got it, except that if you had a 1920x1080 display & you fed it a 1080i signal, it would be amazing, but if you fed it a 720p signal, it wouldn't be as good. its kinda hard to compare unless you had a 1080i & 1080p, that would really seperate the two "technologies". take for example 480i & 490p, go compare those Happy

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OTA 1080p?
Sep 26, 2005 11:52PM PDT

Will there ever be 1080p over-the-air broadcasts? Or is 1080p only for HD-DVDs because OTA doesn't have enough bandwidth?

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ATI HDTV Tuner
Sep 27, 2005 12:05AM PDT

So if I had a HDTV tuner card in my pc, and my monitor goes between 800x600 - 1600x1200. To watch a 1080i broadcast, what resolution would look best? By the way, my monitor is not widescreen and is CRT.