1080i vs 1080p

[ericschand]

Starting a different thread:

Re: $99 DVD player from Toshiba this Boxing Day

Originally Posted by Table 5

It's the A-3, which is basically the lowest end model Toshiba makes. Just be aware that its top ability is 1080i, and not 1080p. It might not make a difference to most, but people should realize that 1080p is what's considered full HD. Either way, still a great deal.

I have a question, something I read on the internet about 1080i
vs 1080p for movies. Not for TV shows, movies only.

Movies are filmed at 24 frames per second.

Your TV supports 60Hz (or 60 frames per second).

Since 24 does not go evenly into 60, they raise it to a common
denominator of 120.

So a movie will display iterate 5 frames over 2 seconds (120 frames).

That's why you have something called "3:2 pullup".

The pattern would be similar to 1-1-1-2-2-3-3-3-4-4-etc.

For 1080i, the pattern is 1a-1b-2a-2b-3a-3b-4a-4b-etc.

Essentially comparing the patterns, 1080i is almost similar to 1080p
for a movie. (A TV show would be 1080p, as that's how they are
filmed)

Is this true? Is this how TV's work? If so, then a 1080i HD-DVD
player would be "good enough"?

ers

[photon]

Most of what I've read says that there is no visual difference between 1080i and 1080p as long as whatever's doing the integration (TV, or whatever) is doing it correctly.

1080p contains no more information than 1080i.

I think I posted a link in the large home theatre thread.

Moving to the correct forum as well.

[SarichFan]

1080p is largely a marketing term... I haven't seen any difference between 1080i and 1080p..

Hell I can't tell much of a difference from 720p to 1080i outside of a minor sharpness increase in 1080i

[Old Yeller]

In anything 50 inches or less, if you're sitting more than 5 feet from the TV (you will be), it's impossible for human eyes to tell the difference.

When you get into the 58 - 72 inch range you're more able to tell the difference between 1080p and 1080i.

[metallicat]

Originally Posted by Old Yeller

In anything 50 inches or less, if you're sitting more than 5 feet from the TV (you will be), it's impossible for human eyes to tell the difference.

When you get into the 58 - 72 inch range you're more able to tell the difference between 1080p and 1080i.

So it's basically not worth the money to buy a 1080p TV if you are getting 50" and less? Even watching HD-DVDs?

[BlackEleven]

The pull-up (and/or pull-down) method you describe is correct, but it doesn't really explain the different between interlaced (1080i) and progressive (1080p).

Interlaced video is designed to reduce the amount of data that has to be transferred. It was originally designed for older televisions that didn't have the technology to draw an entire frame fast enough so it would only draw a portion of the frame (draw one line, skip one, repeat). The next frame would then contain the missing portion of the first "half" of the frame. These "half-frames" are known as fields. In 24 fps video, there are 48 fields per second.

Progressive is what you'd expect if you knew nothing of interlacing. A frame is just an entire image.

Where you may see the difference between progressive and interlaced pictures is during motion. With interlaced video, rapid motion in the picture can cause change between two fields creating blurring artifacts since the two "halves" of the images don't add up to make the same whole image. Where this is noticeable is every third frame because of the 3:2 pullup method you described. However, since these frames pass really quickly, its hard to notice unless you're looking for it specifically or pause the video. Quite honestly, the vast majority of the time, there won't be any noticable difference.

[Jagger]

Originally Posted by oilers_fan

So it's basically not worth the money to buy a 1080p TV if you are getting 50" and less? Even watching HD-DVDs?

I'm a total noob at this stuff but I believe he was referring to 720p or 1080i compared to 1080p. Coud be wrong though. There is a distinct difference between 480p and 1080p, at least to my eyes! I've been blown away by this difference on my new 42" TV. I never thought that I would be bothered, by the better quality, but it's been well worth the purchase.

[ericschand]

From what I can see, and I sit about 10 feet from my 52" TV,
I cannot really tell the difference between 720p and 1080i/p.
The only way I can describe is that if you were to put a small
sized "XYX" on the screen, with 1080 I know that it is supposed
to be different, I'm just not sure what the difference is. In 720p
it's more or less "fuzzed" out, so I don't really know there is a Y
instead of X in there, or that there is any difference at all.

A perfect example seems to be in hockey games. When the
players go across the ice to change lines, you can tell that
there are different letters on the jerseys in 1080i mode.
You may not be able to read the letters, but you can tell
they are different letters. In 720p, you cannot really make out
any letters, it's blurry. Or you might judge that a player
is wearing the A vs the C in 1080. In 720, again, you can't
tell the difference.

However, my question is, for movies, and movies only, what is
the difference between 1080i or 1080p? Is there really any
difference? From what BlackEleven wrote, it doesn't sound like
it.

ers

[Bobblehead]

There is 2x as much data in 1080p as there is in 1080i

Actually, let me clarify that. There is twice as much data in 1080p60 as there is in 1080i60. It is generally understood that there are 60 frames per second, but in Europe it is 50 fps.

So a 1080i set RECEIVES (and that is important, I'll explain why in a second) the odd lines 30 times a second and the even lines 30 times a second. 1080p receives all the lines 60 times a second.

I specified "receive" because LCD and Plasma TVs are, by their very nature, progressive screens. They ALWAYS display every line every time they refresh. That is how the technology works. So when one of these screens wants to display any interlaced feed, they need a way to de-interlace the feed. This is one of those areas where some companies cheap out, and their screens just don't look as good. A good TV will have a good de-interlace processor.

So why did HDTV initially offer 720p or 1080i, and only recently 1080p?

Data throughput.

Which is to say these numbers being thrown around are only the number of lines vertically. The true resolutions are 1920x1080 (for 1080i or p) and 1280x720 )for 720p). So when you think about how much data actually has to be received and processed by the TV, with 720p it is 1280x720x60frames per second = 55,296,000 pixels every second. With 1080i it is 1920x1080x30frames per second = 62,208,000 pixels every second. 1080i and 720p send a similar amount of data, relatively speaking. However, 1080p is double 1080i = 124,416,000 pixels. No TV service in North America offers 1080p service. The cable networks and satellite carriers would need to double their capacity to carry the same number of HD channels.

So yes, there is a huge difference (data-wise) between these different standards.

ericschand - when you mention the differences you see between 720p and 1080i, is this on the same tv? Because then you get into another place where some TV manufacturers save money. The processor that receives the input (be it 720p or 1080i) then fits it onto your screen which may be 720 or 1080. If it is 720 to 720 or 1080 to 1080, no problem. But if it is 1080 to 720, what does it do with the extra lines? Or 720 to 1080, where does it create the missing lines? (all in the 1/60th of a second before the next screen shows up). That is a huge reason why some High-Definition TVs show "regular" TV (also called SD - standard definition) so much better than others. SD is 480i, so it is tricky to get that showing nicely when the HD tv set needs to figure out what to put on those extra line. How can it stretch the picture to fit without making it look like crap. Smart people have patented very nice solutions to these problems. But they charge for them, and so manufacturers looking to shave $15 of their cost of a set may decide another solution looks "good enough".

Salesmem will say people should buy 1080p, and I myself will probably go this route, but I also know that 1080p vs 1080i will only ever affect High Def DVDs and video game consoles. People will buy 2 or 3 more TVs before Broadcasters, or, more importantly, signal carriers (cable/satellite), finally switch to 1080p.

In the end, it all comes down to what your eyes can see. Myself, I know how all the specs work, but that is no substitute for using your eyes. Find something that looks good to you. Calibrate it as best you can (or hire someone to do it - if you drop $2K on a TV, spend the extra couple hundred or so to get a profession to set it up so you get what you paid for), and then don't read any ads or check out prices. Just enjoy your set.

[ericschand]

Originally Posted by Bobblehead

ericschand - when you mention the differences you see between 720p and 1080i, is this on the same tv?

Yes, on the same TV. Note I am talking about viewing the incoming
Shaw HD signal (1080i) first at 1080i, then forcing it down to 720p.
The "difference", like I mentioned, I would not be able to detail it to
you, just know there is a difference (as in the player names on the
back, I could tell that the letters are different but not actually read
the name. In 720p, not so much.)

BTW, the best hockey game I saw was Penguins vs Bruins, in Boston,
last week. I don't know what lighting levels they set, or what they
did to their cameras, but I could view every scratch, snow, etc on
the ice. I have never seen that before in 2 years of HD viewing.
The level of detail was amazing, and you could make out lettering
on the puck as it sat there.

Usually the ice looks as one large white area, rarely do you see any
detail in it. The puck you can see differences, but seeing the letters
was cool. Player names, if they were directly facing the camera,
were very distinct as well. Wonder what they did that made it
different than all the other games?

I didn't bring this one down to 720p because...why??

ers

[photon]

Originally Posted by Bobblehead

There is 2x as much data in 1080p as there is in 1080i

Actually, let me clarify that. There is twice as much data in 1080p60 as there is in 1080i60. It is generally understood that there are 60 frames per second, but in Europe it is 50 fps.

But what sources actually provide 1080p60?

Broadcast TV is 720p/60/1080i/60. High def movies are 1080p/24 (which requires less bandwidth than 1080i/60). The only ones I can think of is maybe some games on the PS3 or Xbox might render at a full 1080p/60, though most are rendered internally by the console at 720p/60 (or even lower!) and upscaled.

So in theory you are right, in practice though there should be no visible difference since there's actually no difference in the amount of actual data.

If there is a visible difference it's a result of the processing that's going on in-behind the scenes.

All that said, I see no reason not to buy a 1080p panel at this point, the prices are so low now.

[nfotiu]

Originally Posted by ericschand

However, my question is, for movies, and movies only, what is
the difference between 1080i or 1080p? Is there really any
difference? From what BlackEleven wrote, it doesn't sound like
it.

ers

There is only a difference if you have a display capable of showing 1080p24. That is, it supports 24,48,120Hz refresh rates. The benefit is that you get 1 to 1 displaying of the frame, instead of relying on processing to fudge the 24 frames into 60. The benefit is that it eliminates judder.

If your display doesn't support an exact multiple of 24hz (and by far the majority don't), then 1080p doesn't give you much, if anything.

[GoinAllTheWay]

Man.....long gone are the days you would base your tv purchase purely on screen size, eh? Like someone said, the best thing to do is go out to BestBuy or something and just look at all the screens side by side showing the same image. Find one that looks best to you, buy it and forget about all the rest. It's the only way to keep your sanity after buying a tv these days.

[photon]

Originally Posted by GoinAllTheWay

Man.....long gone are the days you would base your tv purchase purely on screen size, eh? Like someone said, the best thing to do is go out to BestBuy or something and just look at all the screens side by side showing the same image. Find one that looks best to you, buy it and forget about all the rest. It's the only way to keep your sanity after buying a tv these days.

Even that can be bad, the TV's settings might be all screwed up (or even intentionally set bad to drive you to more expensive TV's).

Buying from a place that allows returns is great, then you can take it home, try it out, and if you don't like it exchange or return it.

[Table 5]

Originally Posted by photon

Even that can be bad, the TV's settings might be all screwed up (or even intentionally set bad to drive you to more expensive TV's).

No kidding. I ended up buying a tv that looked absolutely atrocious in one store, but i knew it had a quality picture because i had seen it in another one, and had some pretty great reviews on avsforum.com

I do think there is a limit to which anyone should research this stuff before going crazy but a smart consumer should know the basics of 720 vs. 1080, pros of 120hz, and the fact that contrast ration is marketing bull.

[LockedOut]

Originally Posted by photon

But what sources actually provide 1080p60?

PC??

[photon]

Originally Posted by Table 5

No kidding. I ended up buying a tv that looked absolutely atrocious in one store, but i knew it had a quality picture because i had seen it in another one, and had some pretty great reviews on avsforum.com

I do think there is a limit to which anyone should research this stuff before going crazy but a smart consumer should know the basics of 720 vs. 1080, pros of 120hz, and the fact that contrast ration is marketing bull.

Yeah, I'm terrible for doing so much research on a purchase that by the time I actually make a purchase the next version is usually out in a few weeks

The thing is usually people who care about the quality (that is to say people who would likely even notice the difference in quality) are the ones that will make an effort to find out about it.

Originally Posted by LockedOut

PC??

Very true! Though if you are playing a movie from the PC the original source is important.

[Bobblehead]

Originally Posted by photon

Yeah, I'm terrible for doing so much research on a purchase that by the time I actually make a purchase the next version is usually out in a few weeks

The thing is usually people who care about the quality (that is to say people who would likely even notice the difference in quality) are the ones that will make an effort to find out about it.



Very true! Though if you are playing a movie from the PC the original source is important.

Wheras I research the hell out of things but usually wouldn't be able to tell the difference between that or the cheaper models.

The thing is, I've been burned by cheaper models before - they seem great until they lose quality and break down sooner. Then I end up thinking if I had only spent the little bit more then I would be happier with my puchase, and over the life of something like a TV, being happier every time you watch is more important than saving $100 up front. I'm willing to pay for quality (but not marketing).

[Table 5]

Originally Posted by photon

Yeah, I'm terrible for doing so much research on a purchase that by the time I actually make a purchase the next version is usually out in a few weeks

This is no lie, but I haven't been able to buy a new computer for 3 years now, because I'm always waiting for the "next improvement". Every time i'm 90% sure I want to replace my mac, I hear of some stupid rumor off of one of those sites touting the next big advancement, and I end up waiting to get it. By the time that features comes out, there's a new one on the horizon.

[Burninator]

When I'm watching HD tv my tv will say 1080i at the top. I am truly getting that or not?
My tv is a Sony KE-42M1 and I am using a Shaw HD PVR box with an HDMI cable.