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1080i question.


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#1 of 4 OFFLINE   David Ren

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Posted August 05 2006 - 02:43 AM

Question: If I'm watching a film broadcast in 1080i/60, there should be no advantage of 720p or 1080p, right? I would assume since interlacing combines 2 fields to make one full frame, I would still get 30 full frames, and since films are shot with 24fps, that's more than enough. Or am I misunderstanding the whole process? how many frames per second does the 1080p on HD-DVDs use?

David

#2 of 4 OFFLINE   Cees Alons

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Posted August 05 2006 - 04:55 AM

Right. Of course, 720p would never be an advantage, because it's a lower resolution.

"Going to 1080p" could be a disadvantage even, if the frame-sequence is de-interlaced improperly (there are circumstances that it could happen).

Once the image is constructed properly (every line at it's proper place in the proper frame Posted Image ), it doesn't matter how you look at it exactly. Most current (non-CRT) monitors display the whole picture at once anyway (some people erroneously call this progressive: of course it isn't, it's the whole picture at once).


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#3 of 4 OFFLINE   David Ren

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Posted August 05 2006 - 01:02 PM

Quote:
Originally Posted by Cees Alons
Right. Of course, 720p would never be an advantage, because it's a lower resolution.

Really? I heard people say that 720p has some advantages, since it is progressive. I've heard still images look better in 1080i and moving images look better in 720p. But for film, it probably wouldn't matter since it's filmed 24fps.

#4 of 4 OFFLINE   Cees Alons

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Posted August 05 2006 - 01:20 PM

On a CRT, interlaced is better than progressive, because it doesn't flicker as much (to the eye).

On LCD and plasma screens, it doesn't matter, because the image is presented as a whole at once.

On TV (broadcasted) images, from a TV camera or camcorder, interlaced images could have slight errors in moving parts (motion artifacts), but that isn't so when the source is film. Those images are scanned film-frame after film-frame in total.

Progressively transferred images don't have a higher spatial resolution than interlaced images, so 720p is never better than 1080 (i or p).

Assuming, of course, that the images don't have other flaws.


Cees