Hi bimmzy - I'm not sure if you're flaming or not, but I'll take the bait and assume you aren't. Where are you getting your information from?
The fact is that 1080i is square pixels, just like 1080p. The only difference in pixel aspect ratio comes if you choose to shoot 1080i on low-end consumer products like HDV cameras.
In regard to resolution differences, 1080i footage that originated on film and has had 3:2 pulldown removed has exactly the resolution (1920x1080) as 1080p does. No more, no less.
Agreed on the "p" vs. "i" sharpness when you start talking about the way material is shot. If it was shot progressive (as all major motion pictures are), it's always going to look sharper. Some applications are better shot interlaced (sports, for example) because, even tough you get effectively half the vertical resolution, you get double the temporal resolution. That means smoother motion and, even though the resolution is technically halved on any given "frame" out of the 59.94 per second, the way your eye works at those frame rates (and the fact that each field is actually captured at the right place in the 1920x1080 framework) blends fields together and the perceived resolution loss is actually slightly less. If you pause on a frame, it'll look half rez vertically. When playing, it will look 75% or so, but smoother.
Hope that helps to clarify some myths and misperceptions that might be floating around!
Cheers,
Kevin
Without sounding controversial,
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i think you may be adding to the myths.
A pixel aspect ratio of square pixels for 1080 is a panacea. Its also the internationally agreed standard for real 1080P.
But, most broadcast cameras still fall short of the 1920 x 1880 resolution. Though I do accept Kevin's point that square pixels in 1080 is the "technical standard", but that's not my point!
In the real world of HD broadcasting having 1920x1080 resolution is great, but the manufacturers of HD equipment arent really playing an image quality game. Instead theyre trying to maintain profit margins in a tough and competitive market.
About 95% of current 1080i cameras have 1440 pixels horizontally (rather than 1920 pixels), thus reducing the ratio to 1280/1440 = 88.9% of horizontal resolution at best.
In the future all 1080i HDTV cameras will offer the full 1920 pixels. many popular models are still limited to 1440 pixels, and if you factor in the issues of display resolutions also, pixel stretching is very much a reality.
Interlaced or progressive? ESPN, ABC Sports, and Fox Sports in HD cover and broadcast sporting events in the 720p/60 format. The BBC broadcasts in 1080i currently (though they have plans to move to 1080p for the 2012 Olympics) as do allot of European broadcasters, despite the EBU's insistence that 720p should be the interim standard.
The reason why sport is often originated in 1080i (50/60) is because, like with 720p (50/60) its cheep, and only consumes half the bandwidth of 1080p (50/60). Other than that there is no advantage of shooting interlaced over progressive.
60p gives the same or better 'temporal resolution' (smooth motion) as 60i, without the massive drop in vertical resolution, attributed to interlaced systems.
"Everybody seems to agree ...... that progressive scanning gives improved motion portrayal.... The choice between 1080i and 720p is thus a balance between static resolution and motion portrayal: 1080i offers better static resolution whereas 720p offers better motion portrayal." EBU
With film and its inherent 3:2 pul-down for SD and HDTV and its resultant cross-frame, cross-field interpolation, Even feature films are at risk of interline-twitter in 1080i. this results in motion artefacts being introduced particularly where the action is fast and furious.
My real bug-bare is that the displays we are being sold seldom live up to expectations.
If you put an HD signal though an HD flat panel display, its gonna make it look great, regardless of the 720p/1080i/1080p argument. But we never see the pictures as they where originated!
It will be a while before we'll see SED and FED flat displays. These promise a leap in image quality, but FED isn't due until 2009 at the earliest, and SED for consumers, later still (if ever).
So what am i saying?
..... Don't buy an HDTV quite yet!
I'll shut up now!
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