Simple? question about 1080i vs. 1080p

Can someone answer this for me? My understanding is that p means progressive scan and i means interlaced. Now, that's a refresh rate (and thus bandwidth) difference, NOT a resolution difference as I understand those terms. So the same number of pixels are being drawn, it's just that one takes twice as long to draw those pixels. Is that correct? Everyone seems to constantly say that "p" gives one higher resolution. That must mean:

1. I don't know what interlacing means.
2. Those terms are not used correctly when it comes to HDTV.
3. People are wrong -- they have the same resolution, but one draws slower.

Which is it?

Jim

The resolution is the same, but 1080i draws 540 lines per 1/30th of a second, whereas 1080p draws all 1080 lines per 1/30th of a second. (Or whatever other than 1/30th of a second, depending on frame rate.)

Wikipedia

Number 3, people are wrong.

I prefer the look of progressive scan, interlaced looks cheap.

EDIT: Screw 1080, the future's 2160p.

ANOTHER EDIT: On second thoughts, maybe 4320p is the future?

What I think is crazy is they hope to have Super Hi-Vision the broadcast standard in Japan in 2015!

While we're doing TV resolutions, I've got a "simple?" question about standard def. My DVD player has just gone tonto, and I need a new one. Progressive-scan, which used to be a high-end feature of DVD players when I were a lad, now seems to be present even on the £20 Sainsbury's jobs. But they all refer to progressive scan on component outputs. My telly, despite being an LCD with native resolution 1280x768, doesn't have component inputs -- only Scart. Is there such a thing as 480p/576p over Scart? Are there DVD players that do it, and, if so, is it likely that my telly will understand it?

Peter

I'd bet there isn't a standard.

Quick background:

Back in the bad old days, your analog cathode-ray-tube TV would sweep left to right, top to bottom, painting the images on the screen. They wanted 60 frames per second, but they didn't have enough bandwidth, so they did 60 "fields" per second, where one field was the even lines and the other was the odd lines (Europe was 50 fields per second...). There was (barely) enough persistence in the phosphors on the screen that the even-line would still be giving off light while the adjacent odd-line was being painted. There was enough fuzziness in the electron-beam that it didn't really matter.

Fast forward to HDTV. The HDTV boffins defined two different HD "standards": 720p and 1080i. 1080i has more than 2x the vertical scan lines of standard def, and way more pixels horizontally, but is still interlaced. This was because it was cheaper to hack a CRT-based TV to do 60 fields per second of 540 lines than to do 60 full frames per second of 720 lines. For plasma/LCD/etc., it was cheaper to do progressive scan at a lower resolution. Thus, the 1080i vs. 720p dichotomy was born. Nobody expected that CRT would just flat out go away so quickly, otherwise 1080i would never have happened.

1080p, of course, has its own variants. There's 1080p/24, which is 24 frames per second -- movie mode. Then there's 1080p/60, which is pretty much the ultimate.

Gone what?

S'cuse my American lack of experience with the English language.

I have to assume your player has gone 'tits up'. Is that right?
I wonder what the root of 'tonto' is...

"tonto" means "dumb" or "retarded" or "not very bright", in Italian. I don't know if that matters in this case, but it seemed to fit well enough

OK, this is sort of what I thought the deal was. That's for all the great responses. Very helpful.

Now if you have a plasma or LCD that says it's both 1080i or 720p, what's the deal with that? I understand the bandwidth idea, but those two formats have different resolutions. What's going on here? Seems like marketing speak is using technical terminology again...

1080i doesn't indicate the resolution of the display.

You have to look carefully at what the set actually lists as its display resolution, regardless of what inputs it accepts. Many TVs can downscale an incoming high resolution signal. And any even without downscaling, a set only needs 540 lines of resolution to display 1080i.

A TV that advertises 1080i/720p has at most 720 lines of resolution.

EDIT: Let me rephrase that... A TV that advertises 1080i/720p has at most the capability to display an HD resolution of 720 lines (1280x720), using a display that is likely that same native resolution or perhaps 1365x768 or maybe even 1422x800. Get the actual display's native resolution to find out what you're buying and always carefully test a set beforehand to see if it meets your requirements.

My 1080i/720p set has 768 lines.

Cheers

If you see a TV that advertises 1080i/720p I would only guarantee that it accepts those resolutions and scales them appropriately to it's native resolution. Only trust the "native" resolution of the panel.

As Mark says there is essentially no such thing as a "720p" panel. About the only 720p display I've seen is a projector.

Apart from the Hitachi/Fujitsu panels you can't get a 1080i flat planel. Everything other panel is always progressive and the internal processing will need to de-interlace and scale (in the case of 768p) a 1080i signal and scale a 720p signal (in the case of a "768p" or "1080p" panel).