What is the difference between 1080i and 1080p?

Question

What is the difference between 1080i and 1080p?

Answer 1

Here's an in-depth article about the differences and similarities:

http://reviews.cnet.com/4520-6449_7-6361...

Answer 2

not much

Answer 3

There's a lot of confusion about 1080i and 1080p. First of all, I'll explain what both are, and how this confusion arises.

There are two parts to these hi-def numbers. The first is the number itself, which refers to the number of horizontal lines that make up the image. Standard-definition TV consists of around 575 visible lines, while high-definition TV has either 720 or 1,080 lines. The second part is the letter, which denotes whether the signal is interlaced or progressively scanned.

In standard-definition TV, each picture frame -- of which there are 25 per second -- is composed of two fields. Each of these fields contains half the information that makes up the whole picture. On a traditional CRT, these two fields are shown one after the other, very quickly. This happens at a rate so fast your eye can't tell, so you see one solid image. This is known as interlacing.

This technique is well suited to broadcasting because it saves bandwidth, and CRTs handle the signal so well you can barely tell it's even happening. Plasmas and LCD screens don't work in the same way -- instead, they show whole frames successively. This is known as progressive scan. Normal TV signals must be converted before they can be displayed.

The fact that flat panels don't use interlacing means that there is no such thing as a 1080i LCD or plasma. Instead, these screens will offer a native resolution of either 720p or 1080p. If a flat-screen TV is touted as 1080i, it really just means it's a 720p TV that converts a 1,080 line interlaced signal into a progressively scanned 720 line one. To have the 'HD Ready' label, all TVs must support 720p and accept input signals of 1080i.

There have been a number of TVs that have 1080p panels -- ones with a native resolution of 1,900x1,080 pixels -- but couldn't support 1080p, so would down-convert it internally and then scale it back up for display. This is every bit as shoddy as it sounds, and TVs doing this should be avoided at all costs.

All of this makes the choice between 1080i and 1080p simpler, because you can decide which TV best suits your viewing habits.

If you watch a lot of normal TV and want to watch DVDs and possibly some high-definition TV via satellite or cable, then you can easily manage with a 720p set, especially if you are looking to buy a TV under 37 inches. It's doubtful that Sky and other broadcasters will ever send 1080p signals over the air -- it's quite simply uneconomical to do so.

If you play a lot of games on a PS3 or Xbox 360, like watching movies on either HD DVD or Blu-ray and need a screen size of more than 37 inches, then you're probably going to want to get a 1080p TV. Although it's not essential, you are more likely to see the benefit of a 1080p TV with this kind of material.

Answer 4

1080i is interlaced, while p is progressive. progressive is much better, it fills in the pixel lines on the TV screen more frequently, giving a better, sharper image.

Answer 5

I agree with everything Jack explained in theory, but the numbers are wrong for the United States. He may be talking about PAL in Europe, but then the numbers aren't exacty right for there either as I understand PAL. In the US, standard definition TV is called NTSC3.58 (National Television System Committee on a carrier at 3.58 megacycles) and Broadcast Grade NTSC is 525 lines. Field A is the odd 262 1/2 lines, then field B is the even 262 1/2 lines. 3.58 megacycles was chosen as a carrier for the United States television system because we get power at 60 cycles and 3.58 is a close approximation to a multiple of 60. Since the carrier frequency is 3.58 megacycles, the number of fields is chosen based on a division of the carrier. 60 fields per second interlaced together, make one frame of video every 30 seconds.

Nothing has changed for HDTV except it's called ATSC (Advanced Television System Committee), the data is sent digitally (8 bit vestigial sideband) instead of analog and the displays have to process faster to create a greater number of pixels per field--60 times per second for interlaced, or an even greater number of pixels per frame 30 times per second for progressive.

As Jack said, interlacing saves bandwidth. Each television channel has only 6 megahertz of bandwith and sending half of the picture at a time cuts bandwidth usage in half. In addition, television-white (6504 kelvin) requires 59% green, 30% red and 11% blue. Broadcasters do not send green because of the heavy bandwith requirement. The TVs figure out the green by subtracting red, blue, horizontal sinc and vertical sinc from 100%.

Stated more simply:

With 1080i you are looking at half the picture at every given moment in time. With 1080p, you are seeing the entire picture at every given moment in time. That's why it looks better, particularly on a larger display.

Answer 6

i is in 1080i and P is in 1080p..............lo....

hehehe  :)

Answer 7

The big difference in the terms, of course,  i for interlaced and p for progressive, which indicate how the image is stored and how it is displayed.

Answer 8

The i means interlaced and the p means progressive.

It is to do with the way the lines on the TV screen scan.

With P they go one two three and so on and with I they go 2 4 6 8 and then they go 1 3 5 7 9 on the next scan.

For things that dont move much you will not see much diferance.

P is better if things are moving fast [like formula one or horse racing.]

Answer 9

i means interlaced

p is Progressive

this is talking about the picture and

how quickly each frame is processed.

i is interlaced which means a larger groups of lines, creating each frame which isn't as sharp or fast.

p is progressive, which is a group of faster frames, which in turn gives you an over all better picture.

here is the listing lowest to highest

480i (standard Boob tube)

1080i ( some newer flat screen tubes)

480p (some of the older HD tv's, ok kinda mediocre def.)

720p (some newer HD tv's have this, good definition)

1080p (latest HD tv technology highest definition)

Answer 10

1080p has better quality of picture than 1080i