The ads say its a 720p but it also shows HD channels in 1080i. HOW??????

Question

Ok, I thought I had a good grasp on this but now??? I bought a Samsung 32" HD LCD, Model# LNT-3242hx/xaa 5 months ago. When I first bought it at circuit city, the in-store displays said 1080i. Now for the past 3 months, every online search I do about this model, says only 720p. Even Samsungs own website says this models a 720p. BUT... I am clearly able to watch HD cable TV channels in both 720p & 1080i (depending on that channels format). I also am able to play my PlayStation 3 in 1080i. I can even use my PS2 in 1080i as long as I use the HD cable (Pr,Pb,Y). I know for sure that its in1080i by simply pressing the info button on the remote. I dont use a cable box. I have the cable cord connected to the back of the TV, And I am able to watch various channels in 1080i along with the HDMI and Component inputs. The computer monitor input only goes to 1360x768. Now the question is: When they say 720p, do they mean JUST the resolution for PC monitor? This is clearly confusing to me.i KNOW I am getting 1080i resolution regardless of what any ad says. Is this crazy? CAn anyone make sense of this??????

PS: I also contacted Samsung and asked the same question plus techs on the TV, but still no answer. The TV is registered and under original warranty with them.

Answer 1

My best guess about this discrepancy is that the TV can accept an *input signal* of up to 1080i, but the native resolution of *the display itself* is only 720p.

In other words, you can fire a 1080i signal into the TV - and the info display tells you this - but the signal gets down-converted to 720p for display. That's the only possibility I can think of.

The difference in quality between 720p and 1080i is not considered to be all that great, especially on a TV with only 32" screen size, so I would not worry about it too much.

Answer 2

He may be a top contributor but he is somewhat wrong.

Most (if not all) 720p televisions are also 1080i televisions.  P simply means progressive which means that every horizontal line of pixels is refreshed simultaneously.  I simply means interlaced which means that every OTHER horizontal line of pixels is refreshed simultaneously.

Basically it comes down to the resolution of your tv.  720p sets use "scaling" to produce great images from a 1080i set.  

There is a lot of very technical information about this subject all over the net.

Here is one simple quote, "correction. While 1080i is 540p because only 540 lines at diplayed at any given time (interlaced) but 720p displays all 720 line at anygiven time.

The general rule of thumb is that fast action, sports, video games, look better with 720p.  1080i is better for some tv shows and movies.

Whether your tv is displaying a "true" 1080i image gets very technical.  So, yes, it is.

Answer 3

If you dig into the specs for your HDTV, you will find that it's LCD display has a native resolution of 1366 x 768 pixels.

The second number (768) is the number horizontal rows of pixels. That means when you watch the screen you will always see a 768p image. That's the way the LCD was made; that's the only thing it can do.

If you don't believe this, get yourself a good magnifying glass and take a good close look at the screen. You can actually see the rows of pixels.

If you feed it a 1080i signal it will just down convert the signal to 768p. If you feed it a 480i signal it will up convert it to 768p.

In theory, all this converting degrades the signal quality, so if you have a choice it's probably best to give it a 720p signal.

Giving this HDTV a 1080i signal instead of 720p just makes the TV "work" harder to get an inferior result.

Or you could just try both with some fast action images. If you can tell any difference at all, the 720p will probably look better.

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>I also would like to know if a TV is 720p can it display channels in 1080i?

A 720p HDTV can display a channel that is broadcast in 1080i. But it does not display the program in 1080i.

A LCD screen always displays its native resolution. In your case it's 768p.

To display an image in 1080i, an LCD has to physically have 1080 rows of pixels. A screen that only has 768 rows of pixels obviously can't display all of the information in a signal designed for a 1080 row display. That's why all 720p HDTVs have scaler circuits to calculate a 720p (or 768p) signal that approximates the 1080i input.

>ALso if theres a specific website that anyone can steer

There are many web sites on the subject but most seem to assume that the reader understands the concept of "native resolution", "interlacing", and scaling. This is sort of a "catch-22"; if you understood those concepts you would already know the answer to your questions.

The third link below isn't too bad.

Perhaps the most important thing is that it doesn't really matter that much with a 32" screen. Human eyes can only resolve so much picture information; as a practical matter most people can't tell the difference between a native 768p and 1080i display on a 32" HDTV.

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As for "Lukester"'s answer, well, perhaps he can explain how a row of pixels that don't exist can be refreshed.

RichB on the other hand, guessed a 100% correct answer.

Answer 4

Cables are important to remember when dealing in the digital world. They won't change the status of your TV but it could affect your actual picture viewing experience.