What are 1080i displays? - Blu-ray Forum

Raymond23 · 08-16-2009, 05:44 PM

In the last few years, I have purchased flat screen plasmas that are "1080i" displays. I've read on these boards that there really isn't such a thing as 1080i. That there are truly 768p.

So, I am confused as to what these TV's really are.

One of the model numbers is TH-42PX6U (Panasonic).

Can anyone offer clarity? Thanks!

crackinhedz · 08-16-2009, 05:49 PM

digital tv's always display in progressive.

The only true 1080i displays would be analog CRT/rear projection.

Rob J in WNY · 08-16-2009, 06:13 PM

More a 'signal' than a standardized display these days, 1080i refers to the 'interlacing' of two 540 pixel 'fields' into a 1080 total pixel image.

For movie content at 24p (24 frames per second), quality de-interlacing can produce a very high quality image - near or as good as 1080p. For VIDEO based content, with its higher inherent frame rate (60 frames per second, typical), your results will vary, but it still usually maintains very high quality. Interlaced video tends to have more visual artifacting as one field may stagger its motion in relation to the next field, but again, quality de-interlacing by a quality video processor can all but eliminate this.

720p and 1080p signals are 'progressive' in nature, meaning each frame is displayed immediately without separate fields to interlace together. The motion is inherently smoother, but, in the case of 1080p, twice the digital video bandwidth is required to display the full frames in real time. That's why 1080p is the latest consumer-grade technology out there - it's the best at the consumer level, and is the current standard for Blu-ray video. Cable and satellite receivers generally only receive 1080i video or 720p video at best, due to the lower bandwidth (and reduced data management) required to carry them.

To be sure, a properly displayed 1080i image can yield better visual resolution than a 720p image - because you get more pixels in the end result. Adherents to the superiority of 720p do have a point - the motion of 720p can be smoother in appearance, which can yield superior imagery in faster-motion video, such as sports and action videos.

Then, enter the world of pulldown conversion in conjuction with 1080i (or any interlaced video) on a 60Hz television display (and for that matter, progressive video as well). That's another topic, but is closely related to the quality of the motion smoothness and video quality!

Wow, I hope that wasn't too confusing. I did try to make it as simple as possible. You can search these forums for more information. I'm sure there will be more responses on this very fascinating subject.

bhampton · 08-16-2009, 07:37 PM

Hey,

Here's my understanding... correct me if needed.

Once there were several resolutions that qualified as HD .... 720p, 1080i, 1080p and maybe even some others.

1080p became a popular choice and was dubbed FULL HD and so on.

Lots of 720p sets are sitting around and need to be sold so they had to get 1080 somewhere in the description so they started calling these 1080i even though they have nothing to do with 1080i.

Maybe mathematically somehow 720p and 1080i are equal... but ... I think rather there is just a need to hand off these left over 720p panels before everything goes to 1080p.

-Brian

Anthony P · 08-16-2009, 11:42 PM

a digital display will have pixels, what are pixels, it is short for picture element and is what the picture is made of. In essence it is a small box that can only display one colour at a time. The pixels define the resolution of your display, in your case, your TV can show 768 (tall) x 1024 (wide) of those boxes.

Now in the olden days of analogue CRT TVs the image was drawn one line at a time, so what happened was that by the time it drew the last line the first line faded way too much, so what they did is invent interlaced and so the TV drew the first line of info, skiped the second then the third... once it did the odd lines it went back and drew the even ones, now in the early days of digital displays some manufacturers on some models would do the even and odd rows in the same way, but now (and yours) they show all the pixels and refresh all the pixels at the same time and that is known as progressive. That is where i and p come from.

Now you don't only watch TV, maybe you watch VHS tapes, DVDs, BDs, maybe a cable box or satelite box are connected. These other boxes send an image to your TV as well, and they need to talk the same way so they understand each other and an image is shown on your TV. So what happens when they say your TV accepts 1080i is that if the device sends a 1080 x1920 i image then it will know what to do with it. The same if you send a 720 x 1280 p image. what ever you send to the TV the TV will need to take it and display it as 768 x 1024 p because that is all it can display.

Now why call it 1080i, 1080 is bigger and most don't understand what 768x1024 means. In other words, trying to make it sound as fancy as possible.

syncguy · 08-17-2009, 02:18 PM

The main reason for calling a 720p TV, 1080i is it's ability of that TV to accept 1080i signal . So it can be called 1080i since it can display a 1080i signal (although it has to convert that to 720p for display).

My_Two_Cents · 08-17-2009, 03:54 PM

Quote:

Originally Posted by syncguy

The main reason for calling a 720p TV, 1080i is it's ability of that TV to accept 1080i signal . So it can be called 1080i since it can display a 1080i signal (although it has to convert that to 720p for display).

Actually, it converts it to the set's native resolution, which would technically be 768p (in most cases).

syncguy · 08-20-2009, 04:34 PM

Quote:

Originally Posted by Ricshoe

Actually, it converts it to the set's native resolution, which would technically be 768p (in most cases).

Yes. some displays are native 768p and some 720p.

TheJesus · 08-20-2009, 04:58 PM

I have a Mitsubishi 55" HDTV, which I bought in the early days of HD. It still is a very nice TV, and has better color than any LCD that i have seen. It only accepts a 480P or 1080i signal, which kinda screws me on PS3 games that only output at 720P.

My_Two_Cents · 08-20-2009, 11:12 PM

Quote:

Originally Posted by syncguy

Yes. some displays are native 768p and some 720p.

I've never seen a native 720 lines set. Not doubting you, just never have seen one.

syncguy · 08-21-2009, 01:47 AM

Quote:

Originally Posted by Ricshoe

I've never seen a native 720 lines set. Not doubting you, just never have seen one.

Some examples. There could be more.

http://www.mwave.com.au/newAU/mwaveA...p?SKU=36010298

http://www.projectorcentral.com/720p_projectors.htm

My_Two_Cents · 08-21-2009, 02:00 AM

Quote:

Originally Posted by syncguy

Some examples. There could be more.

http://www.mwave.com.au/newAU/mwaveA...p?SKU=36010298

http://www.projectorcentral.com/720p_projectors.htm

Projectors, yes, but I was refering to fixed-pixel displays (TVs).

dobyblue · 08-21-2009, 02:25 AM

Quote:

Originally Posted by crackinhedz

digital tv's always display in progressive.

The only true 1080i displays would be analog CRT/rear projection.

Hitachi also have manufactured a line of interlaced 1080 plasmas using ALIS (Alternating Lighting of Surfaces), illuminating even then odd lines allowing for the correct display of a 1080i source. I believe in Europe Sony, Philips and Fujitsu also used this technology before 1080p became commonplace and these guys left the plasma game.

syncguy · 08-21-2009, 05:51 AM

Quote:

Originally Posted by Ricshoe

Projectors, yes, but I was refering to fixed-pixel displays (TVs).

Okay. In addition to projectors, RPTVs could be 1280x720 as well. Not sure about the flat panel displays.

08-16-2009, 05:44 PM	#1
Raymond23 Special Member Member since:Jun 2008 Home Theater Gallery:7 Blu-ray collection:235	What are 1080i displays? In the last few years, I have purchased flat screen plasmas that are "1080i" displays. I've read on these boards that there really isn't such a thing as 1080i. That there are truly 768p. So, I am confused as to what these TV's really are. One of the model numbers is TH-42PX6U (Panasonic). Can anyone offer clarity? Thanks!

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08-16-2009, 05:49 PM	#2
crackinhedz Super Moderator Member since:Feb 2007 Home Theater Gallery:10 Blu-ray reviews:8 Trading Score:19	digital tv's always display in progressive. The only true 1080i displays would be analog CRT/rear projection.

08-16-2009, 06:13 PM	#3
Rob J in WNY Blu-ray Guru Member since:Dec 2008 Location:'Western' N.Y. State (MEMBER OF THE "ECPP")™ Home Theater Gallery:24 4K collection:30 Blu-ray collection:486 iTunes collection:1 Blu-ray reviews: 15	More a 'signal' than a standardized display these days, 1080i refers to the 'interlacing' of two 540 pixel 'fields' into a 1080 total pixel image. For movie content at 24p (24 frames per second), quality de-interlacing can produce a very high quality image - near or as good as 1080p. For VIDEO based content, with its higher inherent frame rate (60 frames per second, typical), your results will vary, but it still usually maintains very high quality. Interlaced video tends to have more visual artifacting as one field may stagger its motion in relation to the next field, but again, quality de-interlacing by a quality video processor can all but eliminate this. 720p and 1080p signals are 'progressive' in nature, meaning each frame is displayed immediately without separate fields to interlace together. The motion is inherently smoother, but, in the case of 1080p, twice the digital video bandwidth is required to display the full frames in real time. That's why 1080p is the latest consumer-grade technology out there - it's the best at the consumer level, and is the current standard for Blu-ray video. Cable and satellite receivers generally only receive 1080i video or 720p video at best, due to the lower bandwidth (and reduced data management) required to carry them. To be sure, a properly displayed 1080i image can yield better visual resolution than a 720p image - because you get more pixels in the end result. Adherents to the superiority of 720p do have a point - the motion of 720p can be smoother in appearance, which can yield superior imagery in faster-motion video, such as sports and action videos. Then, enter the world of pulldown conversion in conjuction with 1080i (or any interlaced video) on a 60Hz television display (and for that matter, progressive video as well). That's another topic, but is closely related to the quality of the motion smoothness and video quality! Wow, I hope that wasn't too confusing. I did try to make it as simple as possible. You can search these forums for more information. I'm sure there will be more responses on this very fascinating subject.

08-16-2009, 07:37 PM	#4
bhampton Blu-ray Count Member since:Aug 2007 4K collection:981 Blu-ray collection:2537 DVD collection:67 Blu-ray reviews: 6 Trading Score:18	Hey, Here's my understanding... correct me if needed. Once there were several resolutions that qualified as HD .... 720p, 1080i, 1080p and maybe even some others. 1080p became a popular choice and was dubbed FULL HD and so on. Lots of 720p sets are sitting around and need to be sold so they had to get 1080 somewhere in the description so they started calling these 1080i even though they have nothing to do with 1080i. Maybe mathematically somehow 720p and 1080i are equal... but ... I think rather there is just a need to hand off these left over 720p panels before everything goes to 1080p. -Brian

08-16-2009, 11:42 PM	#5
Anthony P Blu-ray Count Member since:Jul 2007 Location:Montreal, Canada	a digital display will have pixels, what are pixels, it is short for picture element and is what the picture is made of. In essence it is a small box that can only display one colour at a time. The pixels define the resolution of your display, in your case, your TV can show 768 (tall) x 1024 (wide) of those boxes. Now in the olden days of analogue CRT TVs the image was drawn one line at a time, so what happened was that by the time it drew the last line the first line faded way too much, so what they did is invent interlaced and so the TV drew the first line of info, skiped the second then the third... once it did the odd lines it went back and drew the even ones, now in the early days of digital displays some manufacturers on some models would do the even and odd rows in the same way, but now (and yours) they show all the pixels and refresh all the pixels at the same time and that is known as progressive. That is where i and p come from. Now you don't only watch TV, maybe you watch VHS tapes, DVDs, BDs, maybe a cable box or satelite box are connected. These other boxes send an image to your TV as well, and they need to talk the same way so they understand each other and an image is shown on your TV. So what happens when they say your TV accepts 1080i is that if the device sends a 1080 x1920 i image then it will know what to do with it. The same if you send a 720 x 1280 p image. what ever you send to the TV the TV will need to take it and display it as 768 x 1024 p because that is all it can display. Now why call it 1080i, 1080 is bigger and most don't understand what 768x1024 means. In other words, trying to make it sound as fancy as possible.

08-17-2009, 02:18 PM	#6
syncguy Blu-ray Guru Member since:Mar 2008	The main reason for calling a 720p TV, 1080i is it's ability of that TV to accept 1080i signal . So it can be called 1080i since it can display a 1080i signal (although it has to convert that to 720p for display).

08-20-2009, 04:58 PM	#9
TheJesus Active Member Member since:Jul 2008 Location:Baltimore, MD Blu-ray collection:84	I have a Mitsubishi 55" HDTV, which I bought in the early days of HD. It still is a very nice TV, and has better color than any LCD that i have seen. It only accepts a 480P or 1080i signal, which kinda screws me on PS3 games that only output at 720P.

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