1080i T.V. format.

EagerLearner · 12-19-2012, 05:49 AM

Hello High Def Forum community!,

I hope you all are doing well.

For some time now, I have been curious as to why HDTV is broadcast in 1080i instead of 1080p. Is there a technical reason for this? Maybe it is cheaper this way? The technology isn't there yet, at least for mainstream consumer use maybe?

Just curious.

Take care everyone!

Sincerely, EagerLearner

DoctorCAD · 12-19-2012, 05:53 AM

Its not required by the government.

It also wastes bandwidth and is expensive.

**rbinck** · 12-19-2012, 08:31 AM

This may help: Is 720p better than 1080i?

While it speaks to 720p rather than 1080p, the basic issues are much the same.

RBTO · 12-19-2012, 09:06 AM

In 1080i60, half the lines (540) are scanned, digitized, and sent in about 1/60 of a second. In 1080p60, all 1080 lines receive the same treatment and that results in twice the digital bandwidth. 720p60 is allowable because fewer lines (i.e. 720) are used resulting in just slightly more bandwidth than 1080i60.

For broadcasters, digital bandwidth is valuable real-estate and determines the number and type (SD or HD) of subchannels they can send. The less bandwidth, the better, hence 1080i60.

As far as movies are concerned (24 frames per second), there is no need for 1080p at all since 1080i60 will carry every bit of information in a 1080p24 signal (though it may need more compression for over the air use), however for live events (like sports) a progressive signal might be preferred because there is more motion information. That's where a 720p signal excels, and can be sent over the air as a broadcast standard without using excessive bandwidth.

Blu-Rays aren't limited since there is a hardwire connection that can handle the high bandwidth signal.

EagerLearner · 12-19-2012, 05:58 PM

Hello DoctorCAD, rbinck and RBTO,

Thank you all for your contributions!

Regarding your post DoctorCAD, I see. Why does their have to be a requirement from the Government for T.V.? I found the article you linked me to rbinck to be interesting, and your post RBTO helped to clarify the bandwidth issue. Thank you all again!

I am curious about streaming video services though, like Netflix. When I switch from T.V. to Netflix (on a gaming console), the T.V. switches from 1080i to 1080p. Does this have to do with T.V. having a lot of live events and Netflix being pre-recorded shows or no?

Thank you for your replies, they are all greatly appreciated!

Take care!

Sincerely, EagerLearner

**rbinck** · 12-19-2012, 08:29 PM

Most likely the gaming console is set to output 1080p and all video is converted to that format. It is quite possible that the netflix stream is at a totally different resolution coming in via the internet.

jkkyler · 12-19-2012, 09:58 PM

The reason the govt. is involved is because the FCC licenses and regulates the airwaves as a public trust entity. In order for their to be enough bandwidth for not only tv but cell phones air traffic control emergency services radio etc. and to achieve a uniformity some standards needs to be set.

EagerLearner · 12-20-2012, 07:04 PM

Hello rbinck and jkkyler,

I hope you are both doing well, and thank you for your posts.

rbinck: I see, interesting. Unless I am mistaken here, technically, if you are willing to wait for a show on T.V. to come to Netflix, it is actually better in terms of quality (ex. 1080i for T.V. and 1080p for Netflix).

jkkyler: That makes sense, so the Government acts as a regulator, but are they actually in charge of the airwaves solely? Essentially it sounds like they are the role of the moderator, unless I am mistaken.

Take care all!

Sincerely, EagerLearner

**rbinck** · 12-21-2012, 08:53 AM

Netflix picture quality is generally worse than over the air 1080i broadcast. The reason is compression used to allow the video over the internet. And as was discussed in the link referenced since most of the material these days is shot with cameras that capture a full frame (as opposed to interlaced frames) when the video is deinterlaced, the picture is fully restored to the original, thus the same as a picture sent as 1080p. If you spend much time watching a mix of netflix and broadcast you will notice a difference.

Now a caution here would be that once there is something written on the internet, it will stay there forever. Rarely does an author go back and update old writings to bring them up to date. There are pages after pages that deal with interlaced video vs progressive video that were written when the predominate display devices were CRT based. When CRTs were cheaper to build using interlaced video. When cameras actually captured live video that was interlaced during capture. Most of the arguments that favored progressive video over interlaced were based on the technology at the time and are not necessarily valid today.

As far as the government being the regulator it is because it was early on deemed that the airwaves belonged to the public and not any given individual or entity. It was recognized that a standard would be required for radio and television broadcasting in order to prevent chaos that could, and most likely would, occur if the government did not step in to create standards and allocate bandwidth. Thus the FCC came into being. In 1941 when TV was in its infancy the National Television System Committee (NTSC) was formed to create the analog television standards. In 1953 a second standard was introduced that is still the NTSC standard today. In the early 1990's an industry group called the Grand Alliance formed the Advanced Television Systems Committee (ATSC) to develop the digital television standard. This standard was required to co-exist with the established NTSC standards as far as the broadcasting was concerned since bandwidth had already been established. That is the reason why 1080p/60 is not part of the ATSC standard.

For more information these wiki pages will help:

National Television System Committee standards

Advanced Television Systems Committee standards

EagerLearner · 12-21-2012, 08:23 PM

Hello rbinck,

Thank you very much for your post, I appreciate it! You are very knowledgeable!

I see, that makes sense. Regarding NTSC, I remember seeing that on video game boxes. You always wanted to make sure to get an NTSC game instead of a PAL if you are in North America, so I assume there are different committees for each country?

Take care!

Sincerely, EagerLearner

**rbinck** · 12-22-2012, 08:47 AM

Just North America and Europe mainly.

EagerLearner · 12-27-2012, 07:39 PM

Quote:

Originally Posted by rbinck

Just North America and Europe mainly.

Hello rbinck,

I hope you are doing well.

Alright, good to know.

Thank you kindly!

Take care.

Sincerely, EagerLearner

12-19-2012, 05:49 AM	#1
EagerLearner High Definition is the definition of life. Join Date: Dec 2012 Posts: 34	1080i T.V. format. Hello High Def Forum community!, I hope you all are doing well. For some time now, I have been curious as to why HDTV is broadcast in 1080i instead of 1080p. Is there a technical reason for this? Maybe it is cheaper this way? The technology isn't there yet, at least for mainstream consumer use maybe? Just curious. Take care everyone! Sincerely, EagerLearner

12-19-2012, 05:53 AM	#2
DoctorCAD Direct TV Fresh Meat Join Date: Feb 2007 Posts: 2,199	Its not required by the government. It also wastes bandwidth and is expensive. __________________ This post is not to be construed as a slam on plasma TV's nor an endorsement of any other TV technology.

12-19-2012, 08:31 AM	#3
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 15,602	This may help: Is 720p better than 1080i? While it speaks to 720p rather than 1080p, the basic issues are much the same. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

12-19-2012, 09:06 AM	#4
RBTO High Definition is the definition of life. Join Date: Oct 2011 Location: Idaho Posts: 390	In 1080i60, half the lines (540) are scanned, digitized, and sent in about 1/60 of a second. In 1080p60, all 1080 lines receive the same treatment and that results in twice the digital bandwidth. 720p60 is allowable because fewer lines (i.e. 720) are used resulting in just slightly more bandwidth than 1080i60. For broadcasters, digital bandwidth is valuable real-estate and determines the number and type (SD or HD) of subchannels they can send. The less bandwidth, the better, hence 1080i60. As far as movies are concerned (24 frames per second), there is no need for 1080p at all since 1080i60 will carry every bit of information in a 1080p24 signal (though it may need more compression for over the air use), however for live events (like sports) a progressive signal might be preferred because there is more motion information. That's where a 720p signal excels, and can be sent over the air as a broadcast standard without using excessive bandwidth. Blu-Rays aren't limited since there is a hardwire connection that can handle the high bandwidth signal. Last edited by RBTO; 12-19-2012 at 09:10 AM.

12-19-2012, 05:58 PM	#5
EagerLearner High Definition is the definition of life. Join Date: Dec 2012 Posts: 34	Hello DoctorCAD, rbinck and RBTO, Thank you all for your contributions! Regarding your post DoctorCAD, I see. Why does their have to be a requirement from the Government for T.V.? I found the article you linked me to rbinck to be interesting, and your post RBTO helped to clarify the bandwidth issue. Thank you all again! I am curious about streaming video services though, like Netflix. When I switch from T.V. to Netflix (on a gaming console), the T.V. switches from 1080i to 1080p. Does this have to do with T.V. having a lot of live events and Netflix being pre-recorded shows or no? Thank you for your replies, they are all greatly appreciated! Take care! Sincerely, EagerLearner Last edited by EagerLearner; 12-19-2012 at 06:02 PM.

12-19-2012, 08:29 PM	#6
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 15,602	Most likely the gaming console is set to output 1080p and all video is converted to that format. It is quite possible that the netflix stream is at a totally different resolution coming in via the internet. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

12-19-2012, 09:58 PM	#7
jkkyler I bleed for HD Join Date: Nov 2007 Location: Ohio Posts: 7,386	The reason the govt. is involved is because the FCC licenses and regulates the airwaves as a public trust entity. In order for their to be enough bandwidth for not only tv but cell phones air traffic control emergency services radio etc. and to achieve a uniformity some standards needs to be set. __________________ HT- Panasonic TH-50PZ800U 1080p plasma, Panasonic PT-AX200u LCD projector, Elite Vmax Electric 100' screen, Onkyo TX-NR905 AVR, Paradigm Titan Monitor v5 fronts, Paradigm CC-190 v6 center, Paradigm Atom Monitors v5 surrounds(x4), HSU research VTF-2 sub, xbox360+hd-dvd player ,Sony BDP-S550 blu-ray, D*tv H21 HD-DVR Bedroom: Insignia NS-lcd26, Samsung BDP-1400 blu-ray Den - Vizio 20" 1080p LCD + Samsung BD-p1600 Don't believe everything you read on the internet - Albert Einstein

12-20-2012, 07:04 PM	#8
EagerLearner High Definition is the definition of life. Join Date: Dec 2012 Posts: 34	Hello rbinck and jkkyler, I hope you are both doing well, and thank you for your posts. rbinck: I see, interesting. Unless I am mistaken here, technically, if you are willing to wait for a show on T.V. to come to Netflix, it is actually better in terms of quality (ex. 1080i for T.V. and 1080p for Netflix). jkkyler: That makes sense, so the Government acts as a regulator, but are they actually in charge of the airwaves solely? Essentially it sounds like they are the role of the moderator, unless I am mistaken. Take care all! Sincerely, EagerLearner

12-21-2012, 08:53 AM	#9
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 15,602	Netflix picture quality is generally worse than over the air 1080i broadcast. The reason is compression used to allow the video over the internet. And as was discussed in the link referenced since most of the material these days is shot with cameras that capture a full frame (as opposed to interlaced frames) when the video is deinterlaced, the picture is fully restored to the original, thus the same as a picture sent as 1080p. If you spend much time watching a mix of netflix and broadcast you will notice a difference. Now a caution here would be that once there is something written on the internet, it will stay there forever. Rarely does an author go back and update old writings to bring them up to date. There are pages after pages that deal with interlaced video vs progressive video that were written when the predominate display devices were CRT based. When CRTs were cheaper to build using interlaced video. When cameras actually captured live video that was interlaced during capture. Most of the arguments that favored progressive video over interlaced were based on the technology at the time and are not necessarily valid today. As far as the government being the regulator it is because it was early on deemed that the airwaves belonged to the public and not any given individual or entity. It was recognized that a standard would be required for radio and television broadcasting in order to prevent chaos that could, and most likely would, occur if the government did not step in to create standards and allocate bandwidth. Thus the FCC came into being. In 1941 when TV was in its infancy the National Television System Committee (NTSC) was formed to create the analog television standards. In 1953 a second standard was introduced that is still the NTSC standard today. In the early 1990's an industry group called the Grand Alliance formed the Advanced Television Systems Committee (ATSC) to develop the digital television standard. This standard was required to co-exist with the established NTSC standards as far as the broadcasting was concerned since bandwidth had already been established. That is the reason why 1080p/60 is not part of the ATSC standard. For more information these wiki pages will help: National Television System Committee standards Advanced Television Systems Committee standards __________________ www.highdefinitionblog.com www.BlogOfHawaii.com Last edited by rbinck; 12-21-2012 at 08:56 AM.

12-21-2012, 08:23 PM	#10
EagerLearner High Definition is the definition of life. Join Date: Dec 2012 Posts: 34	Hello rbinck, Thank you very much for your post, I appreciate it! You are very knowledgeable! I see, that makes sense. Regarding NTSC, I remember seeing that on video game boxes. You always wanted to make sure to get an NTSC game instead of a PAL if you are in North America, so I assume there are different committees for each country? Take care! Sincerely, EagerLearner

12-22-2012, 08:47 AM	#11
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 15,602	Just North America and Europe mainly. NonMcTubber likes this. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

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