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bytheway1503560018

576p is not HD

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I think you are incorrect in saying that a 1080/50p recording converted to 'i' is a loss of 50%. If I was to record a 1080/25p tape, I can play that tape back (without any change) as 1080/50i. The resolution is the same, its the 'presentation of the frames that is different.

Actually Chris is spot on. It all comes down to the original format. If shot at 24p or 25p (on either HD tape or film) then yes there is no loss in resolution when converting 1080/24p to 1080/50i. The reason being each field is from the "same moment in time" and these fields can be recombined (via simple weave de-interlacing) to form a true 1080/25p format (with each frame shown twice to display at 1080/50p). This is why 1080i usually looks best for film.

However if something was shot on a native 1080/50p or 1080/60p format (not possible at this stage but no doubt it will be in the future) then you are talking 1080 full lines of resolution per frame (1080 lines per 50th of a second). The only way to convert this to 1080/50i is through the normal interlaced conversion process of splitting frames into fields (even lines first field, odd lines the next). This means each motion update, you are only getting 1920x540 resolution, rather than the full 1920x1080 of the original 50p material (or another way to think of is 1,036,800 pixels per 50th of a second vs 2,073,600).

The only way to then de-interlace this material back to 1080/50p is to upscale each field to 1080p through line interpolation (bob de-interlacing) or at best per pixel motion adaptive de-interlacing, as you cant recombine the fields to progressive frames when they don’t line up (as they are from different moments in time). This means with de-interlaced 1080/50p from progressive video based sources you only end up with 540 unique vertical lines per frame.

This is the reason that 720p outshines 1080i for video based material (anything shot higher than 24 frames a second) as you are always getting the full 720 lines per motion update as opposed to 540 of 1080/50 or 60i.

Put simply, if the material is 24p based - 1080i can be the best looking format due to the ability to reclaim the full 1080 lines of vertical resolution. However, anything shot on video at 50 or 60 motion updates a second is far better suited to a native progressive format and can look far superior (particularly when there is a high level of movement such as sport).

This page has come nice clear diagrams illustrating the superiority of a true progressive format when dealing with motion (and is the main reason the American Department of Defence went with 720p over 1080i) -> http://www.atd.net/HDTV_faq.html

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Nice summary Darklord, why can't material recorded at 1080p at 50 or 60 Hz be encoded as 1080i at 100 or 120 Hz, I suppose it takes up the same bandwidth as 1080p 50 or 60 Hz, but DVB does not support 1080p.

What I want to know is how will the studios encode their films on Blu-Ray/HD-DVD: 1080PsF24/25, 1080p24/25, 1080i48/50, ...?

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Nice summary Darklord, why can't material recorded at 1080p at 50 or 60 Hz be encoded as 1080i at 100 or 120 Hz, I suppose it takes up the same bandwidth as 1080p 50 or 60 Hz, but DVB does not support 1080p.

What I want to know is how will the studios encode their films on Blu-Ray/HD-DVD: 1080PsF24/25, 1080p24/25, 1080i48/50, ...?

this was the process used to produce the t2 extreme dvd: http://www.thx.com/mod/products/dvd/digFlow.html

don't know if they'll do the same kind of process for blu-ray/HD-DVD

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Nice summary Darklord, why can't material recorded at 1080p at 50 or 60 Hz be encoded as 1080i at 100 or 120 Hz, I suppose it takes up the same bandwidth as 1080p 50 or 60 Hz

You said it! :P For one these standards don’t exist, secondly there isn't the room to broadcast them anyway (there is barely enough bandwidth for decent 1080/50i in Australia), thirdly even if there was nothing could decode them, fourthly even if such decoding technology did exist, the processing power, bandwidth and technology required to deliver, decode, and ultimately display such standards would be astronomical, and fifthly the DVB-T system doesn’t allow for another over 1080/50i! :blink:

What I want to know is how will the studios encode their films on Blu-Ray/HD-DVD: 1080PsF24/25, 1080p24/25, 1080i48/50, ...?

There is reasonable evidence mounting (based on interesting comments and white papers from Toshiba, Sony and various movie studios) that both Blu-Ray and HD-DVD will store film content as either 720/24p or 1080/24p, and it will be up toe the players to convert to the appropriate format ( i.e. you could set your player to output in 1080/50/60i / 1080/50/60p / 720/50/60p or even 480/60p/576/50p). This makes sense as it means the exact same masters could be used world wide, cutting costs for the movie studios and providing the best experience for consumers. This is certainly feasible with today’s decoding/scaling/frame rate converting technology, so let's hope it’s the case.

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Thanks for the clarification of my earlier post Darklord.

IMHO, for the reasons now explained, 1080i is basically a waste of time. 720P is better for video (i.e. 50 or 60 fps) because it provides better resolution of moving subjects. It also doesn't suffer from interline flicker, so it uses more of its available resolution than an interlace format.

Whilst it's true that 1080i is superior to 720P for film or 24/25P sources that fact that it is interlaced is a disadvantage. Breaking the frame into two fields makes compression more complex and requires de-interlacing by the display. It would be far better to use 1080 24/25P. For the same bandwidth, (and a 24/25P original), 1080 24/25P is the better format.

In the not to distant future "native" resolution will have no meaning. Film will be telecined, or shot, on super high resolution formats (4k+) and scaled to suit the release format.

I really hope HDDVD/Blu-Ray go down the 1080 24P path. I mean, how bizarre will it be if, in the future, we have to watch movies sped up to 25fps and de-interlaced from 1080i discs on our 1080 24P capable displays?

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I couldn't agree more Chris. One of the reasons I stopped posting here for quite a while was due to the many repetitive "debates" I used to get into with a few DBA members over 720p vs 1080i (or even trying to explain why native 576/50p was better than de-interlaced 576i). Unfortunately many people simple look at the 1080 figure and naturally assume because the number is higher, it has more resolution. Some people also incorrectly think that interlace vs progressive is nothing more than the method in which the lines are displayed. Nothing could be further from the truth. In actual fact 720p can often have much higher spatial and temporal resolution, and always looks better for native high frame rate video sources.

It goes well beyond temporal and spatial resolution too. There are many other factors that in real world terms translate into superior picture quality for 720p. The first time I saw ESPN baseball and Ice hockey in 1280x720/60p on a high quality CRT monitor displaying the full resolution pixel for pixel (set to 1280x720@60hz) with no interlaced artefacts whatsoever, it felt like I was seeing true HD for the first time.

These links are all good reading on the subject:

Two Million Pixels are Better than 1 Million Pixels: The latest false argument in favor of interlaced DTV broadcasting – Excellent article explaining the fallacy behind 1080i being a 2 million pixel format - Written by by William F. Schreiber, Prof. Emeritus of Electrical Engineering, MIT.

Broadcast Engineering – Understanding Interlace – An excellent explanation of the interlace format, it’s origins, how it works and its application today. Explains in detail why progressive scan is superior and breaks downs some myths about the actual quality difference between interlaced and progressive scan.

Joe Kane - Digital Video Essentials D-Theater FAQ – An excellent Joe Kane FAQ (Joe Kane is the man!) explaining the difference between the 1080i and 720p formats in relation to the HD D-Theater release of DVE, and why Joe Kane productions backs the use of 720p over 1080i.

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And another:

“I am amazed that anybody would consider launching new services based on

interlace. I have spent all of my life working on conversion from

interlace to progressive. Now that I have sold my successful company, I

can tell you the truth: interlace to progressive does not work!”.

This remark was followed by a spontaneous round of applause from the

audience. When the person was asked to give his name, he replied “Yves

Faroudja” (who is widely acknowledged as the world’s foremost expert on

format converters).

http://www.ebu.ch/trev_home.html

HDTV in Europe

301 Editorial January 2005: HDTV format wars

Philip Laven

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I couldn't agree more Chris. One of the reasons I stopped posting here for quite a while was due to the many repetitive "debates" I used to get into with a few DBA members over 720p vs 1080i (or even trying to explain why native 576/50p was better than de-interlaced 576i). Unfortunately many people simple look at the 1080 figure and naturally assume because the number is higher, it has more resolution. Some people also incorrectly think that interlace vs progressive is nothing more than the method in which the lines are displayed. Nothing could be further from the truth. In actual fact 720p can often have much higher spatial and temporal resolution, and always looks better for native high frame rate video sources.

It goes well beyond temporal and spatial resolution too. There are many other factors that in real world terms translate into superior picture quality for 720p. The first time I saw ESPN baseball and Ice hockey in 1280x720/60p on a high quality CRT monitor displaying the full resolution pixel for pixel (set to 1280x720@60hz) with no interlaced artefacts whatsoever, it felt like I was seeing true HD for the first time.

These links are all good reading on the subject:

Two Million Pixels are Better than 1 Million Pixels: The latest false argument in favor of interlaced DTV broadcasting – Excellent article explaining the fallacy behind 1080i being a 2 million pixel format - Written by by William F. Schreiber, Prof. Emeritus of Electrical Engineering, MIT.

Broadcast Engineering – Understanding Interlace – An excellent explanation of the interlace format, it’s origins, how it works and its application today. Explains in detail why progressive scan is superior and breaks downs some myths about the actual quality difference between interlaced and progressive scan.

Joe Kane - Digital Video Essentials D-Theater FAQ – An excellent Joe Kane FAQ (Joe Kane is the man!) explaining the difference between the 1080i and 720p formats in relation to the HD D-Theater release of DVE, and why Joe Kane productions backs the use of 720p over 1080i.

omg i just read almost the exact same thing on another forum, and then some moron trying to correct the person that was right, saying that 1080i is the bigger res and looks better than his 200 720p HD movies... :blink:

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Just have everybody shoot 1080/25p - they get to keep their bandwith, we get rid of interlacing artifacts and all the the directors can get that film look everybody seems to want these days, and the Americans can put up with their telecine jutters :blink:

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Just have everybody shoot 1080/25p - they get to keep their bandwith, we get rid of interlacing artifacts and all the the directors can get that film look everybody seems to want these days, and the Americans can put up with their telecine jutters :blink:

Fine for movies and drama. No good for news, current affairs, lifestyle programs or sport (i.e. everything that is traditionally shot on video).

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Most American HD viewers say CBS NFL is the best quality and CBS is 1080i.

I have NFL from CBS and from ABC. As well as oodles of sport from ESPN (who obviously went with 720p as it's the superior format for motion portrayal. i.e. sport!).

1080i looks good for sport when there is very little motion (I imagine lawn bowls would rock :blink: ) but any significant movement above a snail’s pace and resolution drops straight to 540 vertical lines, along with your traditional interfield blur, line twitter, aliasing and macro blocking.

720p sport on the other hand maintains crystal clear image quality and consistent detail and clarity even under high motion. It's a bizarre thing to see for the first time, and there's no doubt whatsoever it wipes the floor with 1080i.

The only time interlaced formats work is when they are converted from something that was progressive to begin with (24 or 25p based material) as they can then be easily converted back to progressive by re-interleaving the fields with no loss of resolution. Native interlaced (50i or 60i) video on the other hand is an ancient horrendous format. There’s nothing that can be done to reclaim all that lost resolution, or do away with the many interlaced artefacts. The sooner we move to progressive video the better off we’ll all be (the EBU understand this, hence the reason they are going predominantly with progressive formats, with the aim to eventually move to 1080/50p production).

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If I was viewing a true 1920x1080p display, I'd want to see the full rez. This quote from the US mag AVGuide sums it up for me:

Nonetheless, Sony demonstrated a BD player with its 70” Qualia 006 rear-projection television (see review in The Perfect Vision Issue 61). This was true 1920x1080 resolution from the source to the display. Seeing more than two million pixels of resolution was absolutely breathtaking. As good as 1280x720 HD looks when done right, it pales next to the full two million pixels of which HD is capable. The BD/Qualia 004 picture was nothing short of stunning.

Granted we may be talk film source, yada yada, but that's most of things I want to watch anyway. Primtime filmed TV series and films. I'd like to see better bandwidth used for sport or 720p (the little that I watch).

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If I was viewing a true 1920x1080p display, I'd want to see the full rez. This quote from the US mag AVGuide sums it up for me:
Nonetheless, Sony demonstrated a BD player with its 70” Qualia 006 rear-projection television (see review in The Perfect Vision Issue 61). This was true 1920x1080 resolution from the source to the display. Seeing more than two million pixels of resolution was absolutely breathtaking. As good as 1280x720 HD looks when done right, it pales next to the full two million pixels of which HD is capable. The BD/Qualia 004 picture was nothing short of stunning.

But that's just the thing! With a native 1920x1080p you very rarely would be getting full res with 1080i sources! This quote from US mag Ultimate AV (from a news post yesterday on new native 1080p Mitsubishi sets) sums it all up for me :blink: )

Since there is no 1080p programming of any significance available to consumers, any set with 1080 vertical pixels simply deinterlaces 1080i sources to 1080p. (All microdisplay panels, by their nature, ultimately require a progressive signal, which the set can create from an interlaced input if necessary). In terms of temporal resolution (resolution on fast moving images), 1080i actually has a resolution equivalent to 540p. Only on stationary images will deinterlaced 1080i have a so-called spatial resolution equivalent to 1080p. On anything between fast motion and stills, the resolution falls somewhere between these two extremes, depending on the speed of the motion.

In other words a native 1920x1080p display (such as the awesome Qualia) is not even close to full potential with a 1080i source. In actual fact where native video is concerned 720p will look far better on a native 1080p display.

Granted we may be talk film source, yada yada, but that's most of things I want to watch anyway.

There is always that argument for 1080i, and I agree to an extent. There's no doubt that it can look very good for film based material. However given how close 1280x720p comes in real world terms to 720p even for film based sources, I'd rather have a single HD broadcast format that does everything well, and looks consistantly excellent, regardless of source, rather than one that can only look good with 24p/25p sources. In effect 720p is the "good at everything format". It also compresses far more easily allowing a smoother more detailed image with less macro blocking at similar bit-rates to 1080i. Above all else it never has to go through any type of de-interlacing to be displayed on a native progressive display (which is after all the way all displays are going with the move to flat panels and digital projectors).

Sky HD in Europe has the right idea. Their service and boxes will have the ability to switch between 720p and 1080i on the fly. Meaning consumers get the best of both formats depending on source. It should be noted however that they have said that their service will be predominantly progressive where possible (as will the majority of HD in Europe by the looks of the way things are going).

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If I was viewing a true 1920x1080p display, I'd want to see the full rez. This quote from the US mag AVGuide sums it up for me:
Nonetheless, Sony demonstrated a BD player with its 70” Qualia 006 rear-projection television (see review in The Perfect Vision Issue 61). This was true 1920x1080 resolution from the source to the display. Seeing more than two million pixels of resolution was absolutely breathtaking. As good as 1280x720 HD looks when done right, it pales next to the full two million pixels of which HD is capable. The BD/Qualia 004 picture was nothing short of stunning.

Granted we may be talk film source, yada yada, but that's most of things I want to watch anyway. Primtime filmed TV series and films. I'd like to see better bandwidth used for sport or 720p (the little that I watch).

1080i may be better for film sources than 720p, but 1080 24/25p is better than 1080i, and potentially uses less bandwidth.

I think most people on this forum would be familiar with the basics of video compression, and the fact that progressive is easier to compress than interlace.

We currently have a situation where the film is shot as one frame, then it's divided into two fields (1080i). The two fields are then (in effect) re-combined (to aid efficient compression), then divided again at the STB output until they reach the display where once again they're combined into the frame we started with.

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