I'd like to open up the question relating to 1080i v 1080p in the general context of HD DVD/Blu-ray "film" material.

The poster is suggesting that it is not possible to use the full resolution of Blu-ray or HD DVD if the player outputs 1080i/60 for the following reasons -

Well here's the theory at least :)

If a film, which in nearly all circumstances is progressive, is output with the interlace flag set, then the player can only output half a frame at a time (but twice as often). So the output resolution is half that of progressive output where the whole frame is ouput.

The monitor, seeing the incoming field flagged as interlace must now interpolate the whole frame again because it is a progressive display and can't display interlaced anyway. It knows it is not allowed to use the second field to combine with the first because by definition the i flag says that the second field is temporily displaced by 1 25th of a second. So it uses the second field to create a whole new frame by interpolation again.

On the other hand, if the player outputs 24p then it outputs the whole of the recorded frame at once, and the display uses the whole frame to create the original hi-def image without interpolation, rather than having to guess 50% of each frame.

In practice other considerations also weigh in. Unless the display is a native 1080line panel, the display has to scale whatever it is sent anyway. If the display can't lock to 24fps or the player can't output true 24 frames per second, then the display has to invent every single frame you see.

If you sit far enough away from a smaller display (e.g. 15ft from a 50" display) you can't really see much difference anyway.

All this will become obvious once you plug a true 24p player into a true 1080-line 24p 60" display that does proper pixel to pixel mapping.

Anybody buying an HD player that can't do true 24fps or a display that can't correctly lock to it has been sold a pup, IMO. Whatever else they have they haven't really got a hi-def system.

Ditto SKY HD. For 1080i50 originated material (i.e. sport) its OK. But movies broadcast 50i are in reality only half HD resolution - never mind the huge compression SKY puts them through in the broadcast chain.

Roll on September and the new Pioneer display I say!Tony


The full thead is here for ref -http://www.avforums.com/forums/showthread.php?p=5205048#post5205048

Is this the case ?

Dazzer

Nothing in the post makes sense.

His whole premise is destroyed by this logic:
The monitor, seeing the incoming field flagged as interlace must now interpolate the whole frame again because it is a progressive display and can't display interlaced anyway. It knows it is not allowed to use the second field to combine with the first because by definition the i flag says that the second field is temporarily displaced by 1 25th of a second. So it uses the second field to create a whole new frame by interpolation again.

Wrong. A HDTV will take both fields and combine them to deinterlace into one frame. This is commonly known as weave. What he describes is a bob. Bobbing does cut resolution in half as the even fields are essentially thrown away. Essentially you would be watching 1920x540. The truth is that any HDTV worth the money should handle both forms of deinterlacing.

By his logic then all DVD played on progressive screens are also running at half resolution. If that were true there would have been hundreds of articles over the last decade adviser users not to buy "half resolution" progressive displays like LCD and plasma. Their would be similar articles advising users not to buy progressive DVD players as they would be simply bobbing the 480i output into a 240p signal.

If the only way to get to p from i was bobbing then until HD DVD every single member of AVS would have been watching DVD on an interlaced display (CRT) with non progressive DVD player as doing anything else would result in half the resolution.

Interlaced and progressive (i and p) are transmission formats, not resolution measurements. Both are theoretically 1080 x 1920 pixel resolution.

I'd like to open up the question relating to 1080i v 1080p in the general context of HD DVD/Blu-ray "film" material.

The poster is suggesting that it is not possible to use the full resolution of Blu-ray or HD DVD if the player outputs 1080i/60 for the following reasons -

The full thead is here for ref -http://www.avforums.com/forums/showthread.php?p=5205048#post5205048

Is this the case ?

Dazzer

You do realize that this poster lives in Europe right? The 50Hz is the tip off. A lot has been said about the 1080i versus 1080P issue. They are both 1920x1080 so the resolution will be the same. The eye/brain cannot distinguish the difference or else we would see "flicker" a known problem with the PAL system in the UK. The interlace is happening so fast we see an image in 1/30 of a second versus 1/60 of a second.

The benefit to 1080Px24 is IF you have a display that can refresh at either 72 Hz or 120 Hz - the display gets rid of the 3:2 Pulldown issue otherwise know as "frame judder." This is because film is 24 FPS while video is 30 or 60 FPS.

Distance is the big factor. Sit properly away from your display and most can not see a difference between 768P and 1080P. It only comes into play when yu are sitting closer than you should be. And sometimes very fine text in an ad can be easier to read with a 1080P versus a 768P.

But the statement that if you don't have 1080P - you are "lost" - PURE marketing Bullshit which was started by Sony and their "Full HD" marketing campaign last year to outsell LCD over Plasma because almost all PDP's were 768P.

Go to any CC or BB and stand back 10 feet from a 50" display - then compare displays and tell me you can easily see a difference . . I dare you ;)

You do realize that this poster lives in Europe right? The 50Hz is the tip off. A lot has been said about the 1080i versus 1080P issue. They are both 1920x1080 so the resolution will be the same. The eye/brain cannot distinguish the difference or else we would see "flicker" a known problem with the PAL system in the UK. The interlace is happening so fast we see an image in 1/30 of a second versus 1/60 of a second.

The benefit to 1080Px24 is IF you have a display that can refresh at either 72 Hz or 120 Hz - the display gets rid of the 3:2 Pulldown issue otherwise know as "frame judder." This is because film is 24 FPS while video is 30 or 60 FPS.

Distance is the big factor. Sit properly away from your display and most can not see a difference between 768P and 1080P. It only comes into play when yu are sitting closer than you should be. And sometimes very fine text in an ad can be easier to read with a 1080P versus a 768P.

But the statement that if you don't have 1080P - you are "lost" - PURE marketing Bullshit which was started by Sony and their "Full HD" marketing campaign last year to outsell LCD over Plasma because almost all PDP's were 768P.

Go to any CC or BB and stand back 10 feet from a 50" display - then compare displays and tell me you can easily see a difference . . I dare you ;)

Lee

Thanks. Yes I know he lives in Europe. :)

Dazzer