CurtPalme.com Home Theater Forum

garysorenson · Posted: Tue Aug 26, 2008 6:54 pm Post subject: 1080i VS 1080p

How much of a noticable difference is there between 1080i and 1080p. I dont think my NECPG9 will do P, but I'm just curiose

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

My 8500 isn't supposed to be able to do 1080p either, but I just tried it with my PS3, and I prefer it. My setup isn't perfect and I don't have any uber-modified magic high-bandwidth MP boards, so I don't *fully* resolve 1080p. In a 1-on-1-off SMPTE pattern, I resolve the horiz lines OK but the vertical lines aren't very visible.

So I don't *fully* resolve 1080p, and the picture is a little soft, but I like it better than 1080i. Twitter from alternating scan lines drives me nuts. The 1-on-1-off SMPTE patterns flash like a neon sign Smile

but of course you don't watch those very often. But it's often visible on horizontal edges, and I don't like that.

kschmit2 · Posted: Tue Aug 26, 2008 8:14 pm Post subject:

try 1080i96 on your 9PG

if you sit at roughly 1.3x screen width you should not have scanline visibility problems

ecrabb · Posted: Tue Aug 26, 2008 8:26 pm Post subject:

Even 1080p/60 direct from a source may look better than 1080i. As Kai alluded to, it depends on how sharp your projector is and what your viewing angle is (a product of screen size and seating distance).

Personally, I sit about 9-10' from a my 8'-wide screen, and 1080i scan lines are VERY visible on my G70. 1080p is awesome - VERY film like. 60p judder hasn't bothered me so far.

Gary, same here. Vertical lines soft, but 1080p is so film-like with a movie playing. It almost looks like 35mm film without any pixels or scan lines. Phosphor grain is more visible than anything else!

SC

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

Yeah, grain is terrible on 8500's.... Sad

ecrabb · Posted: Tue Aug 26, 2008 9:16 pm Post subject:

That's the "bad" thing about good focus and optics - you can see everything, including the bad stuff. What tubes are in your 8500, Gary? AC or LC?

SC

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

It's a basic 8500. AC, with 180DMB22 tubes. Grainy buggers. The 8500LC uses the same tubes so I assume it's no better. I think the P19's used in 9500LC's are a lot smoother, similar to the P16's and P19's used in Sony's.

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia

ecrabb · Posted: Tue Aug 26, 2008 9:57 pm Post subject:

Interesting. I never thought about there being a difference in the quality or size of the phosphor grain from tube to tube. So, the phosphor used on, say a 9" LUG is actually a finer, smaller-grain phosphor powder than what's used on a 180DMB? Is it just a finer grade that's ground to smaller particles or something?

SC

Mr. Green · Posted: Wed Aug 27, 2008 12:33 am Post subject:

I have a 9pg+ and I can't get 1080p to sync. I think 1080i looks really nice on the PS3 though. I only notice scan lines when I'm 6 feet away from a 7 foot wide screen. At 9 feet, I don't see them as Kai suggests.

I may try to play with 1080p again if you have any success, so let me know if you get it to work.

rpruen · Posted: Wed Aug 27, 2008 6:08 am Post subject:

garysorenson · Posted: Wed Aug 27, 2008 3:48 pm Post subject: 1080p

Does the 1080p have more actual picture data, or does it just double up the scanlines?

**kal** · Posted: Thu Aug 28, 2008 1:50 am Post subject: Re: 1080p

Brian Hampton · Joined: 22 Apr 2006 Posts: 1173

Another data point... I prefer 1080p on my G70 as well.

1080i looks good but looks more like video then film.
(Could be prefer-able for somethings where you want a "video" look like concert footage as an example.)

1080p is sharp enough if not fully resolved.
(Text in menus or credits or whatnot appear sharp typically.)

-Brian

garysorenson · Posted: Thu Aug 28, 2008 5:21 pm Post subject: dont quite get it

How does twice the frames per second produce an image clearer? I can see how motion would be more fluid but dont get the clarity thing.

Rdean · Joined: 13 Oct 2006 Posts: 258

I found this article to be informative about 1080p vs 1080i..

http://www.hometheaterhifi.com/volume_14_1/feature-article-1080p-3-2007-part-1.html

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

If you're looking at movies, e.g. BluRay, the disk contains 24 frames per second. That's what they show in the movie theaters, and that's what you'll show in your HT. Nothing in your projector is going to change that.

Your projector can't display 24 "updates" per second. That's too slow and it would be horrifically flickery. In movie theaters they pull a mechanical trick to make it display 48 "updates" per second, but they do that by showing each frame twice.

Your projector can do that, by displaying 48 updates per second, 48Hz. It will display each frame twice, just like in the movie house. It might still be more flickery than you can stand.

You can display each frame 3 times, at 72Hz, or 4 times, at 96Hz. The higher frequencies get rid of any flicker but require more bandwidth from your projector.

(In practice you might not be watching at 24, 48, 72, or 96 updates per second. Unless you have a scaler or HTPC or other hardware that supports those rates, you have to accept whatever your display device gives you. Many DVD players are limited in the update rates they support, because "most" people don't know the difference. So e.g. my PS3 plays BluRay disks at varying resolutions (480p, 720p, 1080i, 1080p), but only at 60Hz. Which doesn't match up very well with 24Hz. Some people notice a slight "judder" (jerky motion) in smooth pans with a 60Hz display, but some don't. I'm lucky and it doesn't bother me so I don't have to spend $1k on a scaler.)

Now, let's say you're doing 72Hz. If you do 1080p, you're displaying the entire frame each time, 3 times in a row. If you run 1080i, you display HALF of the frame each time. 72 times a second, your projector displays every other scan line in the image. This gets a little funky if you're displaying the frame 3 times, since you'll display frame1 lines1,3,5..., then frame1 lines2,4,6..., then frame1 lines1,3,5... THEN frame2 lines2,4,6... frame2 lines1,3,5..., etc.

1080p looks smoother because it's not doing the alternating-lines thing. You end up with fewer motion artifacts. But it's a lot harder for your projector to display it, and not all projectors are capable of doing it well.

Some people prefer 1080i, because it takes half the bandwidth, so your projector can display it sharper. Some people don't like the 1080i "twitter" you sometimes see on horizontal lines (alternating lines flashing on and off), and trade a bit of sharpness for a smoother twitter-free 1080p image.

Mr. Green · Posted: Fri Aug 29, 2008 4:39 am Post subject:

I think I prefer 1080i sharp vs. 1080p soft, even with a jitter. I'm using a PS3 through HDFury and every now and then you see a bit of jitter, but it's not bad. I haven't watched anything for a while, but I 'll try to take note when I notice it happening.

Some of my hard-core PS3 gamer friends like 1080P for games, but do like 1080i more for movies.