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Is 1080p better than 1080i? The truth...
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diabolos
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18. May 2006 @ 15:00 |
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Not necessarily. In the analog world sure 1080p is better than 1080i but the rules are different in the digital domain. See, in the analog domain it isn't possible to reproduce Progressive frames from interlaced content. In the digital world this type of thing happens all the time.
Why Progressive Scan?
First let me start by explaining that all display devices other than the CRT and the Film-Projector are classified as Fixed Pixel Displays (FPD). A fixed pixel display means that there is all ways the same number of active pixels on the screen. Because FPDs must use all of there pixels all of the time they inherently have a fixed or native resolution. All video signals must be converted (scaled) to that native resolution. The biggest point is that all FPDs are also inherently Progressive Scan.
What is Progressive Scan...
http://en.wikipedia.org/wiki/Progressive_scan
What is interlaced Scan...
http://en.wikipedia.org/wiki/Interlace
Where does 1080i come in?
The reason broadcasters use 1080i instead of 1080p for transmission is the same as the reason to use interlaced scan instead of Progressive scan, bandwidth is used more efficiently. That means more channels and/or better video and sound for you!
1080i frames (a frame lasts for 1/60th of a sec.) have 1920x1080 lines of detail (each 1/30th field has 540 lines of detail and each field contains different lines) and so does a 1080p signal! The only difference is that a 1080i frame shows half the detail of a 1080p frame during any part of a frame. Since that is true if the original source was 1080p then that original presentation of 1080p@24fps can be reconstructed by a 1080p set, receiving a 1080i@30fps signal, with good video processing. This process is normally called De-Interlacing.
More on 1080p films...
http://en.wikipedia.org/wiki/1080p#1080i...come_true_1080p
What about frame rates?
The same techniques used with SD programming can still be used with HD programming. With film cameras and 1080p digital cameras, (which account for all movies and some prime-time shows) since they are captured at 24fps, it is possible to get back to say 1080p@24fps even if the TV set is receiving 1080i@30fps from the broadcaster! The process is know as 3:2 pull-down (or reverse 2:3 pull-down).
The only exception to this is 1080p at 60 frames per second (1080p@60fps). Sources like the Xbox 360, PS3, and high-end gaming PCs are capable of producing this ultimate video resolution. The rules for resolution still apply to this format (see later posts below regarding 720p vs. 1080p).
For more information
What is a Video Processor?
http://www.hqv.com/technology/index1/vid...FTOKEN=67750864
What is a Telecine?
http://en.wikipedia.org/wiki/Telecine
More on 3:2 Pull-down...
http://www.projectorpeople.com/resources/pulldown.asp
More on Scaling...
http://www.theprojectorpros.com/learn-s-...ter_scalers.htm
More on Fixed Pixel displays...
http://en.wikipedia.org/wiki/Fixed_pixel_display
Ced
This message has been edited since posting. Last time this message was edited on 12. April 2007 @ 07:39
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dblbogey7
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18. May 2006 @ 17:56 |
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Thanks Ced - always very informative and very relevant.
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ricetrack
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18. May 2006 @ 18:45 |
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i agree with dblbogey7... diabolos knows his stuff. now i think i'll take a 1080p... since it would probably be more useful in gaming.
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diabolos
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7. August 2006 @ 17:28 |
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More logs for the fire...
A quote from the Samsung Blu-ray player found in the September 2006 issue of S&V:
Quote:
Fortunately, nothing much was lost this time. Our comparison tests showed that there was no discernable advantage for the 1080p output versus 1080i anyway. And although I covered this briefly in the main review, it's worth exploring in more detail here given that this is cited by Samsung and in many reviews so far as a key advantage.
The idea here is that the BD-P1000 can somehow benefit from a 1080p TV with a native 1080p input, as opposed to one whose highest input resolution is 1080i, which it deinterlaces to feed its 1080p display. Blu-ray and HD DVD discs are all encoded in 1080p, and Samsung's is the first high-def disc player that can actually deliver a 1080p video output. In theory, this cuts out a couple of steps of video processing, which could perhaps yield a modest picture improvement in some instances. (Film-originated material has a native frame rate of 24 frames per second, and a good, properly functioning deinterlacer should be able to reconstruct 1080p perfectly from a 1080i signal for any source with an original frame rate of 30 fps or lower. Any misstep by the deinterlacer will create at least fleetingly visible artifacts when there is motion between frames, however.)
But Samsung confirms that the BD-P100 doesn't pull 1080p off the disc and send it directly to the output. (We're not sure why, but it may have to do with limitations of some of the player's internal video processing chips.) Besides the necessary frame-rate conversion, from the 24 fps of film to the 60 fps of standard video displays, the BD-P1000 converts the disc's 1080p to 1080i as an interim step, then converts it back to 1080p for output. So to an even greater than normal extent, it should not much matter whether a 1080p display receives a 1080i or a 1080p signal from this player, provided the set has a good deinterlacer. We certainly did not notice any difference between 1080i and 1080p feeds from the BD-P1000 to our 1080p-compliant reference TVs.
The full artical can be read here:
http://www.soundandvisionmag.com/article.asp?section_id=3&article...
Ced
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dblbogey7
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7. August 2006 @ 19:30 |
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I've been trying to find info on this Ced: do the next batch of BD players pull 1080p off the disc and send this directly to the output? I'm trying to do some research on the Sigma decoder chip in the Pioneer and Sony.
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DamonDash
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8. August 2006 @ 04:54 |
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Show me a BD encoded in MPEG-4 on a 1080p set then i will cast my judgement.
This message has been edited since posting. Last time this message was edited on 8. August 2006 @ 04:55
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diabolos
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8. August 2006 @ 07:58 |
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Quote:
Show me a BD encoded in MPEG-4 on a 1080p set then i will cast my judgement.
Cast your judgment about what? 1920x1080 will always produce over 2 million pixels no matter if it is interlaced scan of Progressive scan. Thats the point of this thread, nothing else. I posted the quote from S&V to back up my original clam, I didn't do it to bash Blu-ray.
@ dblbogey7,
I am also intrested in that knowledge. I have a feeling that it doesn't though. I say that because if it did I'm sure one of the Pioneer reps that come to my store from time to time would have touted that as a reason why Blu-ray will win. I also think that 1080p pass through is just too expensive at this point (not impossible) and that both camps are trying to save money by omitting anything not absolutly necessary. But I will look for that info as well.
Ced
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DamonDash
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9. August 2006 @ 05:01 |
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NO,NO i was not saying you was bashing Blu-ray all i was saying is i want to compare the spec by visual.
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dblbogey7
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9. August 2006 @ 13:10 |
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Thanks for looking into it Ced.
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diabolos
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19. December 2006 @ 04:35 |
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@ dblbogey7,
Yes the new Sony Blu-ray player does pass 1080p (1080p@24fps) as well as 1080p60 (from 1080p24 using reverse 3:2 pull-down).
@ everyone,
It appears that there has been some difference in 1080i and 1080p spotted on Sony's Pearl projector. Apparently it can't de-interlace 1080i signals well. I don't know if Sony is doing this on purpose to sell people on the idea that 1080p24 is better than 1080i30 or what but it doesn't make since to me. Everyone else can de-interlace 1080i30 from a film source just fine.
Ced
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OCDgamer
Junior Member
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17. January 2007 @ 09:15 |
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I'm a bit confused, lol. If I am focusing solely on gaming do you guys think I would notice the difference between 1080i and 1080p on a 32"? I mean, would it really be that big a deal on PS3 or 360?
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Member
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17. January 2007 @ 11:40 |
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on a 32' its to small to notice if it was bigger like 46'+ you would notice
jus my 2 cent
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diabolos
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17. January 2007 @ 18:41 |
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The simple answer is no.
It would depend on how well your TV de-interlaces interlaced content. cashman91 is also correct, at 32" 1080p will look the same as 720p at ~2 feet or more.
1080i and 1080p signals pack the same amount of resolution (1920x1080 pixels).
Ced
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OCDgamer
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17. January 2007 @ 18:56 |
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Thanks guys, I really appreciate it.
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dreamer2
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2. April 2007 @ 22:47 |
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thanks this thread resolved my problem.
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diabolos
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3. April 2007 @ 06:04 |
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Your very welcome.
-------------------
@everyone,
I have been getting a lot of questions regarding the need for 1080p tvs since no one plans to broadcast in the format. I want to make it clear that it is possible to watch 1080p on your new 1080p tv set without receiving a 1080p signal. Since the prime-time shows that are in 1080i where originally recorded with 1080p camera your 1080p tv set can reconstruct a 1080p picture.
Basicly:
(studio recording of) 1080p@24fps > (broadcaster transmission of) 1080i@30fps > (TV set receives 1080p@24fps flagged content) 1080i@30fps > (after de-interlacing) 1080p@60fps
Now it isn't true 1080p@60fps but since the source was 1080p@24fps there is no loss in detail although some redundant filler-frames are added.
-Ced
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