# 1080p vs 1080i ? why



## john510 (Aug 7, 2013)

I hooked up my HD unit on my new HD 1080p tv but directv will only go to 1080i , my Roku or antenna will see 1080p ... Am I doing something wrong? its set to native?


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## peds48 (Jan 11, 2008)

Because there is no provider that has 1080p content as this time. plus with DirecTV's 1080p/24 there is virtually no difference when watching 1080i. Don't let yourself be cought up in this "marketing gimmick"


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## JohnBoy (Sep 9, 2011)

Make sure 1080p is checked off in resolution setting.

Also there are a couple of free 1080p movies form Directv Ondemand channel 1000.

I got Rodney Dangerfield Back to School in 1080P free from the listing.

Do a movie search on channel 1000 and look for 1080p movies that are free from channel 1000 (They are mostly mirrored from MGM and Sony channel but are free on 1000).

Once you got your movie fire it up and check your tv resolution to see if it does say 1080p.


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## jimmie57 (Jun 26, 2010)

If you have a 1080p TV, it converts the interlaced 1080i to progressive 1080p before it puts it on the screen for you to see.

Some of the PPV movies are 1080p/24.


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## dpeters11 (May 30, 2007)

But your TV does have to support 1080p/24, not all do. If yours doesn't, you're really not missing anything. As the others said, all channels are either 1080i or 720p.


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## HoTat2 (Nov 16, 2005)

Yeah ...

Don't sweat it though if in the end your set can't receive a native [email protected] Hz format HD program;

About the only advantage of it is if you have a 120 Hz or some other multiple of 24 Hz refresh rate TV, film judder is eliminated.

But most people don't notice this effect on standard 60 Hz sets anyway.


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## peds48 (Jan 11, 2008)

Yeah ...

Don't sweat it though if in the end your set can't receive a native [email protected] Hz format HD program;

About the only advantage of it is if you have a 120 Hz or some other multiple of 24 Hz refresh rate TV, film judder is eliminated.

But most people don't notice this effect on standard 60 Hz sets anyway.
I do not think that 120Hz improves the pictures as the TV is making up frames where there is none. This feature to me inserts "artifacts" in the picture. 


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## HoTat2 (Nov 16, 2005)

peds48 said:


> I do not think that 120Hz improves the pictures as the TV is making up frames where there is none. This feature to me inserts "artifacts" in the picture.
> 
> Sent from my iPad using DBSTalk


Yes, for "video" based material, 120 Hz (or greater) refresh rate TVs need to generate interpolated picture frames between the actual native picture frames which actually does introduce artifacts as a result that some viewers with a sharp eye can see.

But I was referring to "film" based programs that have a native frame rate of 24 Hz. Here 120+ Hz TVs do not produce interpolated frames between the real ones, but simply repeat each film frame some multiple of 24 (5 in the case of 120 Hz set).

This preserves the native film rate and eliminates the judder effect of the 3:2 pull-down process used by standard 60 Hz sets.

However, as I said most people won't notice film judder anyway as its very subtle. In fact the only reliable way I can see it on a 60 Hz set is at the end of a movie when the credits are rolling, you will see a slight jerkiness as they scroll, and who cares about that?


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## Rich (Feb 22, 2007)

I see a really big difference in the PQ of NF's "Super HD" vs the 1080i of D*. Very noticeable after watching NF then switching to D*. But then the eyes adjust and all is good again. 

Rich


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## Beerstalker (Feb 9, 2009)

HoTat2 said:


> But I was referring to "film" based programs that have a native frame rate of 24 Hz. Here 120+ Hz TVs do not produce interpolated frames between the real ones, but simply repeat each film frame some multiple of 24 (5 in the case of 120 Hz set).
> 
> This preserves the native film rate and eliminates the judder effect of the 3:2 pull-down process used by standard 60 Hz sets.


As far as I know this is not true. A 120Hz (or 240Hz) TV will create interpolated frames on 24Hz films if you have that feature turned on (if you have the option of turning it on). So say you have a Samsung 120Hz TV and watch a TV show that is shown in 1080i60. It will take that 1080i information and deinterlace it to create one 1080p30 frame. It will then interpolate 3 different frames to insert between that 1080p30 frame and the next one. For 1080p24 material it will take that 1080p24 frame and interpolate 4 new frames to show between it and the next 1080p24 frame. If you are watching 720p60 material it will upscale that 720p60 frame to 1080p60, and interpolate one frame between it and the next frame.

The only way to not have it interpolate frames in between and to just show the same frame multiple times is to turn that function off (smoothmotion, trumotion, motionflow, etc). However, some TVs don't have an option to turn it off, and other TVs don't have motion interpolation at all so you can't turn it on. This is why you should research this function on any 120Hz or 240Hz TV before you buy it depending on if you like the feature or not (I personally do not like it, so I want to make sure any TV I buy has the ability to turn it off).


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## P Smith (Jul 25, 2002)

it's only one important part of the chain (processing A/V stream); unfortunately you can't get definitive knowledge by reading your manual
it would require more deep research: what video processing chips using and more important - FW implementation (here is different mfgs could make better or worst the processing)

perhaps some magazines having deep pockets to buy all the TV models and expensive test equipment would do the tests and publish reports


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## peds48 (Jan 11, 2008)

As far as I know this is not true. A 120Hz (or 240Hz) TV will create interpolated frames on 24Hz films if you have that feature turned on (if you have the option of turning it on). So say you have a Samsung 120Hz TV and watch a TV show that is shown in 1080i60. It will take that 1080i information and deinterlace it to create one 1080p30 frame. It will then interpolate 3 different frames to insert between that 1080p30 frame and the next one. For 1080p24 material it will take that 1080p24 frame and interpolate 4 new frames to show between it and the next 1080p24 frame. If you are watching 720p60 material it will upscale that 720p60 frame to 1080p60, and interpolate one frame between it and the next frame.

The only way to not have it interpolate frames in between and to just show the same frame multiple times is to turn that function off (smoothmotion, trumotion, motionflow, etc). However, some TVs don't have an option to turn it off, and other TVs don't have motion interpolation at all so you can't turn it on. This is why you should research this function on any 120Hz or 240Hz TV before you buy it depending on if you like the feature or not (I personally do not like it, so I want to make sure any TV I buy has the ability to turn it off).
Yup, this is what I was trying to imply, in less word of course..... 


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## HoTat2 (Nov 16, 2005)

Beerstalker said:


> As far as I know this is not true. A 120Hz (or 240Hz) TV will create interpolated frames on 24Hz films if you have that feature turned on (if you have the option of turning it on). So say you have a Samsung 120Hz TV and watch a TV show that is shown in 1080i60. It will take that 1080i information and deinterlace it to create one 1080p30 frame. It will then interpolate 3 different frames to insert between that 1080p30 frame and the next one. For 1080p24 material it will take that 1080p24 frame and interpolate 4 new frames to show between it and the next 1080p24 frame. If you are watching 720p60 material it will upscale that 720p60 frame to 1080p60, and interpolate one frame between it and the next frame.
> 
> The only way to not have it interpolate frames in between and to just show the same frame multiple times is to turn that function off (smoothmotion, trumotion, motionflow, etc). However, some TVs don't have an option to turn it off, and other TVs don't have motion interpolation at all so you can't turn it on. This is why you should research this function on any 120Hz or 240Hz TV before you buy it depending on if you like the feature or not (I personally do not like it, so I want to make sure any TV I buy has the ability to turn it off).


Hey good info.

And I humbly stand corrected ....


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## dennisj00 (Sep 27, 2007)

There is a difference in PQ if the content is filmed properly. While there's not much content, I remember watching "Bucket List" in 1080p on my 46" Sony that looked incredible. Need to catch it again on the 60". (current listing is only HD)

If I remember correctly, there use to be a 1080p category on the On Demand guide.


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## P Smith (Jul 25, 2002)

You should set base line as watching any movie from BR disk first.


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## LiQiCE (Feb 14, 2006)

TVs have the option of doing interpolation to get a 30fps or 24fps content up to 120hz (or 240hz) which is sometimes called the "Soap Opera Effect", however when you turn that option off LCD TVs which run at 120hz or 240hz will not interpolate and frame double to get to 120hz or 240hz. The reason 120hz is key is because it is divisible by 24fps (5 times), 30fps (4 times) and 60fps (2 times).

What Ho Tat2 says is exactly right - there is no 3:2 pulldown required for 24fps material with a 120hz / 240hz TV.

What Beerstalker says is also true - but that assumes you can't turn the option off. If you have the option off though - you're still running at 120hz (or whatever your LCD TV natively runs at) and the TV is then upping the frames to 120hz by frame "doubling" (or in the case of 30fps quadrupling and in 24fps creating each frame 5 times over).

Plasma TVs have similar capabilities for 24fps content however Plasma TVs do not necessarily have a fixed refresh rate like LCDs typically do -- For example, my Pioneer Kuro Elite can run at 60hz (for 30fps or 60fps content) or 72hz (for 24fps content). The higher end Panasonic Plasmas run at 96hz for 24fps content.

If you watch a lot of movies, it makes a big difference (imho) to use a 24-fps divisible refresh rate versus using 3:2 pulldown. For long panning shots - it is very obvious when you use 3:2 pulldown versus a "native" 24fps.

LCDs also have an issue with lag, their pixel response time is slower than Plasma - so a higher refresh rate also helps to reduce motion blur where it isn't intended.

So 120hz or 240hz doesn't improve the picture per-se, but it can make movies feel more theater-like (as the director originally intended) and it can also reduce motion blur - note that when I say this, I don't mean by turning on the features Beerstalker mentioned like Motionflow, Smoothmotion, etc etc - those unnaturally reduce motion blur. With those options off however, a 120hz LCD TV will still have less motion blur than a 60hz LCD TV - but not unnaturally so (it would look closer to a CRT or Plasma TV with instant response).

Hope this makes sense - sorry if this is a little off topic from the original question.


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