What does "i" in 1024i [resolution] mean?

465

looking at a 42" plasma 1024i x 780

whats the i ?

RE*AC*TOR

interlaced
basically means that it will effectively only show half the image in each frame
over two frames the entire image will be shown.

its the poor cousin of 1024p - which stands for progressive scan

465

RE*AC*TOR wrote:

interlaced
basically means that it will effectively only show half the image in each frame
over two frames the entire image will be shown.

its the poor cousin of 1024p - which stands for progressive scan

Wow! so in othwer words STAY AWAY

WAS;T CHEAP EITHER

Saved me a bomb, cheers

Lump

Eh..... It's Interlaced yes, but European Televisions contain 25 Frames Per Second, at 50 Hertz (The Cycle rate of mains power) As a result there's 2 fields to each frame, half the lines (Even numbers) Are shown in Field 1 and the other half in field 2.... as a result a still frame/field of video will have half the resolution, unless there's a frame store yokey involved.

So It's across 2 fields, as opposed to across two frames. There's 50 Fields in a frame, and 25 frames in a second....

John

MrPinK

465 wrote:

Wow! so in othwer words STAY AWAY

I certainly wouldn't go that far. 1080i is still Hi-Def and looks amazing. In theory 1080p is better alright, but you'll certainly be paying more for it. On a 42" TV though, I doubt you'd even notice the difference.

pH

Strictly speaking all LCDs/Plasmas are progressive. There is not a genuine interlaced display.

the 1024i is probably an ALIS panel of some sort, which SONY and Hitachi use in some units. Some folks swear by them they're by no means cheap, and while they are kindof interlaced they're not interlaced in the same was as a CRT.

http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/home/tv_flatpanel.html?page=2

Go to avforums.com for plenty of long running arguments on the merits of ALIS panels!

full forward

I compared 720p to 1080i on the same screen recently and I think 720p is better but only just. For 1080i or 1080p you need 50" or bigger. Ill be getting a 1080p projector to replace my current standard def one when they become main stream which could be late next year. And thats only of I can get a blu ray or hddvd player that can provide that res. If I was getting a LCD or Plazma TV I would be very happy with 720p. Just my two cents.

pH

You need to be very careful when attempting to compare 720p and 1080i.

720p is a 'simple' format, 1080i needs to be de-interlaced, and the difference between a good deinterlacer and a bad one is considerable.

There are 2 main 'modes' of 1080i - film and video.

In film mode the broadcast is in effect 1080p25 in which each original 1920x1080 film frame has been split into 2 fields (even and odd lines). It is trivial to put these back together on screen as both fields come from a single film frame.

What is difficult is detecting that you should be doing it. For us 50hz people we're looking for panels which can perform 2:2 reverse telecine or 2:2 pulldown. It's extremely hard to check if a panel will do this properly based in manufacturers info, but there are test video sources which will show if the panel can do it effectively.

So for film sources (25 fps after 4% speedup) on a panel which can do 2:2 detection and pulldown then 1080i will be absolutely the best.

However for video sources (genuine 1080i video when there is movement between the 2 fields) you need a damn good deinterlacer to rescue a decent picture out of it. As you can imagine 1920x1080 deinterlacing at high quality is not a trivial proposition and many panels revert to some form of Bob deinterlacing (in effect treating each field as a frame with 540 lines resolution)

As I said 720p50 is much simpler, its practically impossible for a panel to get it wrong. However for film sources you're getting twice the temporal resolution (which is useless as you just end up transmitting the same frame twice for each film field) versus less picture resolution (1280x720).

For fast moving video (sports events) most panels should be able to do much better with 720p than 1080i. Thats not to say a panel with a serious HD deinterlacer/scaler couldn't do a better job with 1080i, but for average consumer panels 720p should be better than 1080i for sports/video sources.

YoYOPowder

465 wrote:

looking at a 42" plasma 1024i x 780

whats the i ?

If its a plasma, chances are its 1024x780 or probably 768 and progressive at that, which is the norm for plasma Where did you read the spec, sounds wrong to me or perhaps misleading, which a lot of websites and DID/Dixons staff are!!