Ok,

I'm sure this has been answered before, but what is the disserence between 1080i and 480p? I know "i" is interlaced and "p" is progressive, but what produces a better picture? My DVD player is a progressive scan player and when it plays on my TV the input shows as 480p. When using my HDTV input to view HDTV signals, it shows up as 1080I (cable compnay). Both produce beautiful pictures. What is considered better though? I see TV's advertising their resolutions when using an HDTV signal and some say 1080i while others say 480p. How do you compare the 2 to determine which TV will give a better picture?

Also, is it true that as of right now there are no Plasma TV's out there that can fully support the 1080i signal?

The 1080 is part of the resolution used, 1920x1080 or 2,073,000 pixels.
480p is 640x480 or 307,000 pixels.
For reference, a regular TV signal is 480i (again 640x480).

480p is not a high def signal, 1080i is. When you are viewing a true HD broadcast (not one that is unconverted from a regular signal) it is technically far superior to 480p in clarity and detail.

The number followed by a letter both specifies the number of lines and the display method used. For example 480p means the picture has a vertical resolution of 480 lines and the picture is progressive (complete frame displayed per scan). 1080i means the picture has a vertical resolution of 1080 lines and the picture is interlaced (every even line is displayed on one scan and every odd line is displayed on the second scan).

With a proper setup, you should have a significantly better picture from your 1080i source than the 480p source when the source is showing a still image. Some high end TVs and especially Plasma, TFT and newer rear projection displays all deinterlace the interlaced sources to get rid of the horizontal line effect.

From what I am aware of, HDTV CRT TVs display all 1080 lines from a 1080i/p source, however most other display types such as plasma, TFT and DLP displays (both front & rear) only have a vertical resolution of up to 720 lines. The reason is that the picture quality of a 1080i source looks much the same as a 720p picture source apart from still images. As interlaced sources draw only half the vertical lines per scan, motion looks worse (although smoother) than from a progressive source.

This also explains the reason way a 1080i source in motion does not look much better than the same 480p source in motion, however the 1080i benefits when the source has a still image.

Hope this helps

I want to thank you guys for your help. So you're saying 1080i is better. That's what I thought. So, here is another question. Say I'm looking to buy a Plasma TV.

TV "A" has the following info:
Resolution = 852 X 480
Display Resolution for HDTV Signals
1080i = 480p
720p = 480p

TV "B" has the following info:
Resolution = 1024 x 1024
Display Resolutions for HDTV Signals
1080i = 1024i
720p = 1024i

TV "C" has the following info:
Resolution = 1024 X 768
Display Resolutions for HDTV Signals
1080i = 768p
720p = 768p

TV "D" has the following info:
Resolution = 1365 X 768
Display Resolutions for HDTV Signals
1080i = 768p
720p = 768p

Where all HDTV Signals are converted to the native resolution of the TV

Now, which of the three will show a better picture? Should I go with the TV that has the highest Resolution or the TV that handles HDTV signals at 1024i since you guys say 1080i is better than 480p? At the moment only HDTV picture output is a matter of concern.

One other question, Most of these TV's upconvert analog NTSC signals for a better picture. For example, 1 TV may upconvert an analog NTSC signal to 480p, 768p or 1024i. Does the TV do this automatically or do you have to enable a special function? Again, would the 1024i be better than 768p and 480p?

My last question. I see that all 1080i signals are converted to no more than 1024i. Is this a limitation of the TV? Are there any TV's you know of that can support the full 1080i signal?

The higher the native resolution, the better the picture as more pixels means more displayed detail.

TV's A & D appear to be 16:9, TV C appears to be 4:3 and I'm not sure about TV B. I would recommend going for a 16:9 display if your main interest is HDTV since most HDTV content is presented in widescreen.

My opinion of the various TVs you listed

TV A does not appear to be a true HDTV since it displays only 480 lines. The best picture you will get out of this even with a HDTV source is the equivalent to a 480p picture.

TV B has a rather unusual resolution. It displays the majority of lines for HDTV, but may use rectangular pixels for doing a 3:2 down-conversion across, i.e. fitting 1,920 pixels in the space of 1,024.

TV C appears to be a 4:3 display going by the resolution. Just note that if you display a widescreen picture on a 4:3 display, either you will lose some of the left & right of the picture if zoomed to reach the top & bottom, the whole picture will be shrunk resulting in black bars below and above the picture (losing detail and overall picture size) or the picture will be shrunken horizontally to fit; making buildings, people and objects look rather tall

TV D looks to be the only true HDTV TV in the list. On a 720i/p source, it will display all the pixels vertically and horizontally on the screen. A 1080i/p source will result in some down conversion, but may not be as noticeable for a 1080i source since an interlaced HDTV picture does not look much better than a 720p apart from a very still picture.

Other features

The upconversion process is standard for all HDTV sets I know of. What the upconversion process does is interpolates the incoming standard definition picture to fill up the resolution on a HDTV picture. Note that this process does turn a standard definition picture into a full high definition picture, much like interpolating a picture from a digital camera into a higher resolution.

I'm not sure why a few TVs use 1024 lines instead of 1080 lines, maybe the first and last 32 lines are often unused since many CRT based TVs often cut off this portion of the picture.

Well.

Here is a link explaining what Interlacet and Progressive is when it comes to TV.

http://www.doom9.org/video-basics.htm

If you set aside what resolution you use, progressive is better quality. But in this case going from 480p to 1080i and you have a HD-ready viewing device I would say 1080i is best, since it give a larger picture and more detail.

If you put it verry basic, interlaced is when frames are blended together and progressive is not blended together.

Anyway read the guide if you wan't to get into it. There are lots of other usefull information stuff there about Hz and so on.