CurtPalme.com Home Theater Forum

johnsmith808 · Joined: 15 Oct 2008 Posts: 100

I notice some pretty faint vertical banding on the left edge of the screen with 1080i, but with 720p, I don't see any. It's about 3 lines from top to bottom. They can only be seen in brighter scenes. It is on all 3 colors.

I have a Playstation 3>3' hdmi to dvi cable>hdfury1>box1020>12' breakout cable>G70.

Any suggestions?

ecrabb · Posted: Thu Nov 20, 2008 10:40 pm Post subject:

Hmmm... Sounds similar to the problem I'm seeing at 1080p... It doesn't seem to be there at 1080i, though (I don't know if it's there at 720p - I don't like 720p and don't run it).

I'll see if can capture it and post it here. I was going to start a separate thread, but here is as good as anywhere if it's the same or a similar problem.

SC

johnsmith808 · Joined: 15 Oct 2008 Posts: 100

I only run 720p for video games since that is the native resolution for most Xbox360 and PS3 games. Very few games are native 1080p. A handful are below 720p, like Halo 3 but are scaled to 720p.

ecrabb · Posted: Thu Nov 20, 2008 10:56 pm Post subject:

Ah, OK. I had read awhile back that most games were rendered at lower res and upscaled... So, I play Halo 3 once in a great while, too but run the 360 at 1080i (and the PS3 at 1080p) exclusively. Is there any benefit in frame rate or playability (or something else) to playing at 720p instead?

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johnsmith808 · Joined: 15 Oct 2008 Posts: 100

The main benefit is sharpness. If you scale a video game from 720p to 1080i/p it will not be as sharp as displaying it in 720p. Native resolution, especially in video games is always best.

That's why I always though it was ironic that playing a xbox 360 or ps3 game on my 720p dlp would be sharper than playing it on a 1080p pj.

Performance wise, most games don't matter, as they are rendered internally at it's native resolution, then scaled. One exception was Tomb Raider Legend, which played a lot smoother at 480p instead of 720p. There may be other exceptions.

I just recently compared 720p versus 1080i on my Xbox360, and it was pretty noticeable.

ecrabb · Posted: Thu Nov 20, 2008 11:20 pm Post subject:

Hmm... OK. I'll have to do some tests. Don't scan lines bug you at 720p? I would think they'd be pretty noticeable, depending on your viewing angle, of course.

SC

johnsmith808 · Joined: 15 Oct 2008 Posts: 100

I guess when it comes to video games, imperfections are more noticeable, so maybe I'm used to it. However, sharpness to me is pretty important in games, so I guess it's a trade-off.

CIR Engineering · Posted: Fri Nov 21, 2008 3:26 pm Post subject:

On your G70, you might have your image too close to the edge of the raster (causing raster ringing). What I usually do on the G Sony projects is move the image as far as it can go to the left side of the raster (facing projector). After that I center the image to the screen. Use the "shift" control to move the image and raster. Then use the "cent" control to move the image inside the raster area.

Be careful, if you place the image too far to the left in the raster it will become non-linear at the edge. This may not be noticeable looking into the lens, but you will be able to detect it on the screen with a grid pattern.

The other cause for the banding could be that your geometry is not well set up. You might want to reset everything to 128 and try again.

craigr

ecrabb · Posted: Fri Nov 21, 2008 3:54 pm Post subject:

Thanks for the help Craig. I don't mean to highjack the thread, but hopefully my questions will add some to the discussion...

I think my geometry is decent, but it's definitely not as good as I could get it on my old 12xx, which was almost digital good. I've fought and fought with the geometry controls and I can NOT get this little bit of wave I have dialed out. I even just did a full setup from scratch a couple weeks ago and I think I may have gotten it a touch better, but it's still quite noticeable - especially on scope material on the edge of the letterbox. It's "W" shape - or I guess it's like "seagull" distortion. Like I said, it's subtle, but noticeable. Any ideas what I could be doing wrong, there?

As for the raster ringing, when I set my machine up, I was intentionally conservative on the throw so as not to get too carried away with maximizing rasters. I'm probably only half way between factory recommended throw and where you could go if you pushed it all the way. I read enough to know that people were having trouble with corner focus so I stayed away with pushing too far. I'll take some measurements tonight and check the raster spacing and post here. Hopefully, between mine and johnsmith's, we can come up with some sort of resolution.

I'd love to start a G70 master setup hints/tips thread. I might make that a little winter project (with help from everybody here, of course). This machine is a hell of a machine. I'm getting an amazing picture out of it, but I know I'm only about 90% of the way there.

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johnsmith808 · Joined: 15 Oct 2008 Posts: 100

I appreciate those suggestions.

Wouldn't the raster position affect both 720p and 1080i? I'm just guessing.

The one odd thing I noticed about my G70 is that when I reset all of the zone convergence to 128, there is one area on the top right of the screen that stays at 200 or so. That is the area that curves downward. It's almost as if from the factory they tried to iron out this problem by setting the zone convergence to a higher level.