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hdtv question

C

captex

i heard somewhere, the best quality hdtv picture has to have a certain dpi (resolution) and there is also 2 types of tubes made. i remember only one of them is L c d, now one these has a good picture quality and the other doesn,t have a good picture. hopefully i'm asking this question on the correct board.

thanks captex
 
You might want to try the engineering board. There are guys there who do both audio and video.

To possibly answer some of your questions...

There are several types of screens for HD. Under 50", you're usually looking at LCD. The other option is a plasma screen, which has some issues with degradation over its lifetime. There are also several projection systems, including the latest(?) called DLP, which uses thousands of tiny microchip-controlled mirrors. It's brighter and sharper than the older projection systems.

As far as resolution is concerned, the highest current standard is 1080P, which is 1080 lines of resolution, scanned in sequence every 60th of a second for an effective frame rate of 60 frames per second. You can probably save yourself a bunch of money be opting for 1080I, or 1080 frames per second interlaced, which means that all the odd-numbered lines are scanned in the first 60th of a second, and all the even-numbered lines are scanned in the 2nd 60th of a second, for an effective frame rate of 30 frames per second.

Since movies, and most other "standard" TV frame rates are between 24 and 30 frames per second, and show full-motion just fine, there's no advantage that humans can see to progressive scanning at that resolution. Not only that, but progressive scanning doubles the bandwidth requirement, which means that OTA, satellite, and cable companies aren't likely to go to 1080P when 1080I works just fine.
 
SirRoxalot said:
There are several types of screens for HD. Under 50", you're usually looking at LCD. The other option is a plasma screen, which has some issues with degradation over its lifetime. There are also several projection systems,
Click to expand...

possibly sooner than one thinks... There has been quite a bit of trouble with burnin on plasma displays - where if a bright object (such as a promotional logo, or the score ticker if you watch a lot of ESPN) becomes a permanent dark spot in the image, even when tuned to some other channel.

Also, they tend to be really, really heavy :)

(two of us had to lift a 63" plasma 4" to slide a stand under it at work yesterday. We were *just barely* able to do it...)

Bulb life for projectors (and the price of replacement bulbs) is something you should consider if looking at a projection HDTV.

Personally, I'm *strongly* leaning in the direction of LCD. Then again, my living room isn't big enough to justify anything bigger than LCD supports.

that, but progressive scanning doubles the bandwidth requirement, which means that OTA, satellite, and cable companies aren't likely to go to 1080P when 1080I works just fine.
Click to expand...

In fact, OTA doesn't support 1080p - 1080i is the highest standard available.
 
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