# 1080 p question Regarding tvs only going up to 1080 i



## dishlover2 (Aug 24, 2008)

I know as it was explained if I understand thing s right 1080 p tv downconvert to 1080i for standard definition channels those not in hd and i means near high definition How would it affect channels broadcasting in 1080p but the model tv supporting 1080i


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## P Smith (Jul 25, 2002)

Why open new thread with same question when you can pick a few threads here with exhausted discussions what explained all the conversions ?


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## Stewart Vernon (Jan 7, 2005)

I'm honestly not even sure I understand what the question is.


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## James Long (Apr 17, 2003)

dishlover2 said:


> I know as it was explained if I understand thing s right 1080 p tv downconvert to 1080i for standard definition channels those not in hd and i means near high definition How would it affect channels broadcasting in 1080p but the model tv supporting 1080i


There are no channels broadcasting in 1080p ... only 1080i and 720p are used for the HD stations DISH carries. SD (standard definition) is 480i.

DISH does offer 1080p content but it is VOD ... video on demand downloaded to your receiver as a file before playing.

If you do not have a 1080p set or your set fails the 1080p test you will have the option of watching in 1080i or other format - whatever your TV can handle.


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## dennispap (Feb 1, 2007)

dishlover2 said:


> I know as it was explained if I understand thing s right 1080 p tv downconvert to 1080i for standard definition channels those not in hd and i means near high definition How would it affect channels broadcasting in 1080p but the model tv supporting 1080i





HDMe said:


> I'm honestly not even sure I understand what the question is.


All of this guys posts are like this. He doesnt use periods and you cant make out what he is saying. Look at any of his other posts.:nono2:


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## James Long (Apr 17, 2003)

Please talk about the DBS topics and not the posters. Thanks!


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## tnsprin (Mar 16, 2003)

James Long said:


> There are no channels broadcasting in 1080p ... only 1080i and 720p are used for the HD stations DISH carries. SD (standard definition) is 480i.
> 
> ....


Although it is probably true that no channels are currently broadcasting in 1080P, there is nothing stopping them from doing so. 1080P24 (which is what is used for these PPV movies) is supported in the US ATSC broadcast standard and some test broadcast using them have been done by various stations.

For OTA all US ATSC receivers are suppose to be able to accept 1080P24 broadcasts, although it is not required that they be able to deliver that to your TV without converting. Also some of the program providers have talked about delivering their material to their cable/satellite outlets in this format in the future.

It would be interesting to know if the Dish receivers HD could handle satellite signals delivered as 1080P24. And it would be interesting if they can deliver this to your TV as 1080P24.


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## James Long (Apr 17, 2003)

Considering what is done to the 1080i and 720p feeds to get them through the satellite pipe I expect that DISH would do the same to 1080p feeds. The current presentation of 1080p is awkward at best ... testing for compatibility every time a 1080p option is chosen.

The codecs are there for displaying 1080p VOD so I will not say it is impossible that 1080p live feeds would ever be passed. But until 1080p becomes more common for networks and set manufacturers I wouldn't expect to see it. 1080p is VOD only for now.

BTW: I'd prefer 1080p24 satellite transport for movie channels and PPV.


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## BattleZone (Nov 13, 2007)

ATSC is irrelevant, as sat doesn't use ATSC to deliver the content.

The vast majority of HDTVs cannot accept 1080/24p input signals; the ability to accept these signals didn't start appearing on HDTVs until a very few 2005 models, and even in 2008, there are still brand new TVs that don't accept 1080/24 signals (we're talking via the line inputs here; remember that the ATSC tuner isn't relevant).

Further, the Broadcom chipsets used in both Dish and DirecTV receivers, up to the current models, don't support 1080/60p output at all. This is a hardware limitation and can't be changed other than to deploy new receiver models with 1080/60p-capable chipsets.

Then there would be the bandwidth issues. Bandwidth is limited as it is, and higher resolution/bitrate broadcasts need higher transmission bitrates. Given that Dish's bandwidth is fixed, that would mean eliminating channels or further compressing channels in order to free up bandwidth for a 1080/24p channel; robbing Peter to pay Paul. That isn't a viable solution either, and if it was, it would make more sense to use the extra bandwidth to reduce the compression on the current, full-compatible 1080/60i transmissions they currently use. But they don't because that bandwidth just isn't available.


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## James Long (Apr 17, 2003)

Compare 1080i 30fps vs 1080p 24fps ... which needs more bandwidth pre-compression?

1080p 24fps is a good choice ... especially for 24fps film sourced channels.


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## Stewart Vernon (Jan 7, 2005)

James Long said:


> Please talk about the DBS topics and not the posters. Thanks!


Sorry if my post seemed bad... I honestly am not sure what question is being asked and was hoping for more info from the original poster.

I wasn't sure if he was asking about 1080p vs 1080i or something about SD vs HD or what. Rather than post all possible answers I was hoping for more info.

Meanwhile... at least for the moment everyone else has already piped in some of what I would have said... only 1080p for FVOD right now, and typically only 1 movie at a time. Also, shouldn't be any resolution difference between 1080p and 1080i anyway so TVs like mine that fail the test (no HDMI) shouldn't really look any different.

Also, would be interesting to see if any movie channels (HBO, SHO, etc) considered moving to 1080p/24 fps in the future since most of their films would be shot that way originally anyway AND as you already pointed out it would actually save some bandwidth over 30fps 1080i.


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## dishlover2 (Aug 24, 2008)

James Long said:


> Please talk about the DBS topics and not the posters. Thanks!


yes, thanks james my apologies I Get deep in thought ,punctuation suffers , sorry about that.


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## Mr.72 (Feb 2, 2007)

James Long said:


> Compare 1080i 30fps vs 1080p 24fps ... which needs more bandwidth pre-compression?
> 
> 1080p 24fps is a good choice ... especially for 24fps film sourced channels.


Yes it is good for that, but little else. Of course 1080i is much, much worse than 1080p24 for 24fps source material (film).

You are not "down-converting" from 1080p24 to 1080i. You are having to do a 3:2 pull-down somewhere and invent new frames to fill in those 6 frame gaps each second. It's much easier to fit 24 frames into a 60fps format such as 720p or 1080p60.


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## racermurray (Mar 21, 2007)

I was always under the impression the more frames per second the smoother the video.
Why would 24fps be better than 60fps?

Thanks,
Murray


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## James Long (Apr 17, 2003)

Matching the source is good. If it has to be changed to something else for display then convert it at the best place.


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## BattleZone (Nov 13, 2007)

racermurray said:


> I was always under the impression the more frames per second the smoother the video.
> Why would 24fps be better than 60fps?
> 
> Thanks,
> Murray


Film has been shot at 24 frames per second since the very first movie ever made. Testing discovered that this was enough frames per second to show smooth motion, while at the same time being few enough frames that the size and cost of film is managable. Moving the frame-rate of film up to, say, 30 fps would mean that 20-minute reels of film negatives would turn into 17 minute reels. Costs for negatives would go up, costs for special effects would go up (digital effects are done by the frame; more frames = more work and more processing time). In the end, it would add several million to the cost of most films, and could be much more than that on an FX-heavy film.

It IS true that higher frame-rates smooth out motion, but that is one of the things that lets your eye instantly tell the difference between FILM and VIDEO. You may not know WHY you can tell, but almost everyone can tell instantly if they are watching something that was shot on film vs. on video.

So, since 24 fps is the standard for film, the BEST way to encode it digitally is to encode at the same frame-rate in a progressive scan. That's what 1080/24p does.

The limiting factor is whether you have a TV capable of displaying that content at 24 frames per second. NO consumer TV made before 2007 could do that, though many models from 2006 can accept 1080/24p input signals (they convert them to 60p, using 3:2 pulldown, in order to display them on their fixed 60 Hz panel, introducing unwanted but unavoidable "judder"). A few high-end sets in 2007, and a larger number in 2008 now offer more expensive display panels and controlling circuitry that can refresh at rates other than 60 Hz, and by using a refresh rate that is an even multiple of 24, and repeating each frame until it has been on-screen for exactly 1/24th of a second, the look and proper frame rate of film is fully preserved.


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## Mr.72 (Feb 2, 2007)

racermurray said:


> I was always under the impression the more frames per second the smoother the video.
> Why would 24fps be better than 60fps?


Because if the source is 24 fps, then these frames cannot be mapped correctly to 60 frames in the destination format because 60/24 doesn't equal a whole number.

So sometimes you have to display three identical frames in a row, and sometimes two. You wind up with jerky motion as a result. Normally I guess they'd map 3 frames, then two, then three, then two and so on until you have displayed all 24 frames in one second.

Now it's much worse with 30fps such as 1080i. At least going 24->60 you have enough time slices to get a relatively even distribution. But with going to 30fps then every fifth frame has to be repeated, so it's like 1-1-1-1-2-1-1-1-2 if you do full frames. Normally I think most interlacers will actually perform a 3-2 frame sequence, but they will use 1/2 scan frames and live with the interlace artifact, since it is better than the motion artifact.

The way the video processor handles these conversions is one of the things that separates the wheat from the chaff.


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## Bill Simonsen (Oct 4, 2002)

James Long said:


> Considering what is done to the 1080i and 720p feeds to get them through the satellite pipe I expect that DISH would do the same to 1080p feeds. The current presentation of 1080p is awkward at best ... testing for compatibility every time a 1080p option is chosen.
> 
> The codecs are there for displaying 1080p VOD so I will not say it is impossible that 1080p live feeds would ever be passed. But until 1080p becomes more common for networks and set manufacturers I wouldn't expect to see it. 1080p is VOID only for now.
> 
> BTW: I'd prefer 1080p24 satellite transport for movie channels and PP.


_________________________________________________________________

I'm sure it is in my mind but I'd swear I can see a diff, on this 52 inches of glorious Sony, 'tween 1080i and 720p- and it depends on network which looks better!
I saw a list somewhere, sometime of what nets broadcast in what Rez- if someone knows where such a list can be found, I'll give you a pound of free seaweed if you're ever in Maine...

-Bill


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## Mr.72 (Feb 2, 2007)

James Long said:


> BTW: I'd prefer 1080p24 satellite transport for movie channels and PPV.


Well of course that would require 1080p24 source material from the movie channel networks. This seems totally plausible since it takes less bandwidth than either 720p60 OR 1080i60.

Less bandwidth, better quality, what's not to like?

oh, yeah. Well it would require our TVs to all accept that signal. Otherwise we'd be leaving it up to the Dish box to convert the 24 to 30 frames. Oh yeah, and it would require dish hardware capable of doing 24fps (which I guess the current setup does), but to make it clean, it would also require 1080p60 output to be compatible with TV sets that will only accept 30 or 60 fps refresh rate.


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## olds403 (Nov 20, 2007)

was it ever determined what the original question was?


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## dishlover2 (Aug 24, 2008)

olds403 said:


> was it ever determined what the original question was?


in the event stations do broadcast in 1080p we with 1080i tvs would be downconverted to 1080 i?


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## Mr.72 (Feb 2, 2007)

> in the event stations do broadcast in 1080p we with 1080i tvs would be downconverted to 1080 i?


Does this mean, "in the event stations do broadcast in 1080, would the signal be converted to 1080i on 1080i TVs?"

If so, then the question is kind of moot, it is predicated upon an invalid assumption.

1080i is a faster refresh rate than 1080p24, the most common, normal 1080p format. So a 1080p24 signal would have to be _UP_converted to 1080i. This would be the job of the Dish receiver and not likely your TV. If your TV cannot handle 1080p24 right now, then there is no way to make it do it.


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## BattleZone (Nov 13, 2007)

Mr.72 is correct.

Dish receivers can ALREADY convert 1080/24p material into 1080/60i and other, lower-rez formats.

The only difference would be for folks who had a TV that not only handled 1080/24p input signals, but also refreshed such signals at a multiple-of-24 refresh rate.


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## Calvin386 (May 23, 2007)

IIP said:


> Film has been shot at 24 frames per second since the very first movie ever made. Testing discovered that this was enough frames per second to show smooth motion, while at the same time being few enough frames that the size and cost of film is managable. Moving the frame-rate of film up to, say, 30 fps would mean that 20-minute reels of film negatives would turn into 17 minute reels. Costs for negatives would go up, costs for special effects would go up (digital effects are done by the frame; more frames = more work and more processing time). In the end, it would add several million to the cost of most films, and could be much more than that on an FX-heavy film.
> 
> It IS true that higher frame-rates smooth out motion, but that is one of the things that lets your eye instantly tell the difference between FILM and VIDEO. You may not know WHY you can tell, but almost everyone can tell instantly if they are watching something that was shot on film vs. on video.
> 
> ...


I have really got my eye on this New Sony 52" Bravia 120hz. The 120hz make this LCD capable of the 24 frames per second...correct?


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## P Smith (Jul 25, 2002)

Check detail specs of the TV set, if it doing 5:5 cadence, then it's good one; if first step 2:3 to 60 Hz then x2 to 120 Hz - mediocre device.


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## BattleZone (Nov 13, 2007)

Calvin386 said:


> I have really got my eye on this New Sony 52" Bravia 120hz. The 120hz make this LCD capable of the 24 frames per second...correct?


Believe it or not, the answer is NO, 120 Hz does NOT automatically guarentee proper 24p support. There are several brands of TVs out this year (Vizio being one of them) that do 120 Hz, and have a version of what Sony calls "MotionFlow", but they don't refresh 24 fps content properly.

The 120 Hz Sonys DO handle 24 fps properly, though. This is limited to the W/Z4100 models and XBR 6/7/8s. And MotionFlow must be OFF.

The definitive list of TVs with proper 24 fps support is here:

http://forum.blu-ray.com/showthread.php?t=5155


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## petej88 (May 1, 2007)

IIP said:


> The 120 Hz Sonys DO handle 24 fps properly, though. This is limited to the W/Z4100 models and XBR 6/7/8s. And MotionFlow must be OFF.
> 
> The definitive list of TVs with proper 24 fps support is here:
> 
> http://forum.blu-ray.com/showthread.php?t=5155


addendum: The Sony XBR4 120 hz also handles 24 fps with motionflow off. It's on a separate list since it is not Sony's current XBR series.


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## BattleZone (Nov 13, 2007)

Thanks for that correction!


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## jboyer (Dec 17, 2008)

Is there something different about ESPN as it appears to look better than the other HD channels?


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## James Long (Apr 17, 2003)

720p?


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## Mr.72 (Feb 2, 2007)

Yep, I bet it's because it's 720p.


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## jboyer (Dec 17, 2008)

Okay. I'm new to this HD thing. Where can I get a good explanation of 1080i, 1080p, 720p, etc without searching through all the posts?


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## Mr.72 (Feb 2, 2007)

It's very simple.

"p" is progressive scan which basically means each frame contains an entire frame's worth of pixels or "lines". 

"i" is interlaced, which means every frame only contains half of the lines that would be required for a full frame (either odd or even numbered lines), and then the next frame must provide the remaining lines, and the whole frame is reconstructed from the two halves in a process called "deinterlacing". 

1080 or 720 refers to the number of lines of resolution. Normally, 1080i/p has 1920 pixels in each line, and 720p has 1280 pixels in each line. So the reconstructed frame for 1080i/p would be 1920x1080 pixels, and the frame of 720p would be 1280x720 pixels.

The common formats are:

1080i60 - 60 interlaced (half) frames per second, which then are deinterlaced at a 30fps rate (only 30 full frames per second).

720p60 60 full frames per second

1080p24 - 24 full frames per second

Also, there are some TVs or other devices (like my Oppo DVD player) which will do 1080p60, which has 60 full 1920x1080 frames per second.

Some channels broadcast or encode their signal at 1080i60, and some at 720p60. There is no broadcast channel I am aware of that does 1080p24, and none do 1080p60. 1080p24 is the common format for Blu-Ray. IIRC HD-DVD supported 1080p60.

And to further add to the confusion, Dish likely is re-sampling many channels, if not all, to create what is known as "HD-Lite", which basically is a scaled-down number of pixels per line. So a 1080i channel may have only 1280 pixels per line instead of the prescribed 1920.

And while I am adding to the confusion, many LCD TVs do not natively display any of these formats. Many do native 1366x768 resolution.


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## BattleZone (Nov 13, 2007)

http://www.cnet.com/hdtv-resolution/

http://en.wikipedia.org/wiki/High-definition_television


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