CurtPalme.com Home Theater Forum

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

I just watched the first episode of BBC's Planet Earth, and I was fairly shocked to see very noticeable banding in several scenes: sun rising over the earth, things like that.

I haven't noticed this in other material. I'm wondering if the disk itself has banding in its signal?? Do the rest of you see this banding, or is something in my signal chain doing it? My chain is pretty basic. This is a Blu-Ray disk, played in a PS3 through a Moome EXT-HD box, to an 8500.

I'll be fairly disgusted if it turns out the "5/5 reference video" Planet Earth has artifacts like that. But I'll be even more annoyed if it turns out to be a weakness in my system. I don't **think** this is a fundamental limitation of the technology, but maybe I'm running into bit-depth issues?

Gary

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Gary I have the HD DVD version here and no banding.

nuttall_chris · Posted: Thu Nov 27, 2008 3:55 pm Post subject:

I have the Bluray version....no banding here.

Chris.

**kal** · Posted: Thu Nov 27, 2008 7:40 pm Post subject:

Never noticed anything like this. Sort of the shots are slightly soft but for the most part it's fantastic.

Kal

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

Hm. Looking at it again today, I don't see it on some of the scenes I thought I remembered seeing it on yesterday. But here's one scene where it's very clear: first disk, title 1, chapter 1, 3:24. Right after the intro of the emperor penguins, it shows a sunrise over the earth. I see very distinct banding on the left side of the screen. Does anybody else see that or do I have something weird going on?

And yes, I'd say it's fairly soft. It's beautiful photography but it doesn't have that amazingly sharp detail you *should* be able to get with HD.

WanMan · Joined: 19 Mar 2006 Posts: 10270

Gary, I often see things one day and not the next. Its the Gin. Mr. Green

Mark_A_W · Posted: Fri Nov 28, 2008 3:00 am Post subject:

Banding can occur in the Colourspace conversion, and if any levels expansion occurs, it can cause banding too.

Try fiddling with any Colourspace options you have.

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

The only "processors" in the chain are the PS3 itself and the Moome box. The EXT-HD doesn't have any color adjustments that I know of. The PS3 has a few settings: Limited (16-255) vs. Full (0-255) range, Y Pb / Cb Pr / Cr Super-White (On or Off), and I think that's it. I haven't tried all permutations of those. I assume I should have Super-White off (may not even be relevant since I think it requires component input on the display), but I'm not sure which video range to use.

Experimenting some, it looks like the BD/DVD Video Output Format was set to Auto, which apparently chose Y Pb / Cb Pr / Cr mode. By setting it to RGB I was able to experiment with the Limited/Full range. It was on Limited (16-255). I set it to Full (0-255) and that helped the banding considerably. It's still just noticeable at the fringe of the sunrise zone, but just barely.

You can't set Super-White in RGB mode.

So apparently RGB, Full Range is the right setting to use? Kal, is that how you run your PS3?

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Gary I believe 16-235 would be the correct setting...

http://www.audioholics.com/tweaks/calibrate-your-system/hdmi-black-levels-xvycc-rgb

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

Well, I believe the PS3 defaulted to YCbCr and 16-235, and that showed the banding. That Audioholics page says RGB has a range of 0-255, so presumably you should run 0-255 if you run RGB. But the page also says the disks are authored with YCbCr 16-235, so you would think YCbCr (with 16-235, presumably, since that's what the HDMI spec calls for and the PS3 doesn't let you change it) would be the best -- but for banding on that sunrise scene, RGB 0-255 was clearly better.

Why? Beats me. If the original is 16-235, you would think leaving it in the original format would be best. Why would rescaling it to 0-255 look better??

I'd better check to see if I can still see blacker-than-black with it set to 0-255...

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Good question but I don't have a PS 3.

Mark_A_W · Posted: Fri Nov 28, 2008 9:24 pm Post subject:

The labels are confusing.

0-255 will leave black at 16 and white at 235. You will be able to pass BTB and WTB.

16-235 will expand the black to 0 and white to 255. BTB and WTW are gone.

Leave it at 0-255. The expansion causes the banding, if it doesn't have proper dithering. Expansion is a bad idea anyway, we don;t need it on our CRTs.

You should see your black level change when you adjust these settings - you need to compensate with brightness.

So, do I get a cookie?

Ray Cendroski · Joined: 22 Apr 2006 Posts: 68 Location: Concord, Ohio

Interesting thread. I saw "banding" in the thread title and was hoping that it might mention the Moome Ext HD.

I'm also seeing banding issues with my Moome Ext HD. I don't have the same Planet Earth episode to try, but the most glaring example for me is in the the movie "The Fall". About 3 minutes into the flic, there's a sepia toned scene where a guy is throwing a rope off a bridge. As the rope falls to the river in slow motion, you can see a full width narrow white band on the screen that follows the motion of the rope end as it moves up and down the screen.

Here's my setup - I'm using a TViX M6500 media player media for mostly Blu-Ray rips played back from hard drives. I have it set up to output 1080i which then passes to an Onkyo 905 with an internal REON processor which upscales it to 1080p and sends it on to the Moome which outputs RGB to my Ampro 4600 CRT projector. I don't have a Blu-Ray player.

To date I've followed conventional wisdom and set the TViX for the 16-235 range. I convinced myself that this had to be correct from all the articles I've read, including the AudioHolics link above. Last night I was bored, and figured I would try Marks suggestion about the 0-255 range. I started with Video Essentials and was surprised to see the "blacker than black" bar was available as Mark said it would be. At first I was disappointed after re-setting black and contrast, but the more I played with it, the better it got.

My arbitrary Tvix black and contrast settings went form -2 and +5 to +8 and 0. I tried some different source material, and the immediate thing I noticed was that I now had "inky black" movie starting screens like at the beginning of 2001. Even better was that everything else looked so good. Movies that I thought looked washed out are now stunning. The differences aren't subtle - everything is now a magnitude better. I think that re-adjusting the range to 0 to 255 has also helped the Moome gamma tracking.

I also noticed something else. There are a lot of cable TV HD broadcast movie captures on the Internet. Some broadcasters (like Premier) are using the newer h264 encoding instead of the older MPEG format standard. The big problem is that sometimes the h264 black levels are shifted. Movies like Zulu and Star Wars 3 have beautiful resolution, but always look grayed out on the TViX. There is a re-muxing tool called Ts4Np_082 which has a "h264 video level" correction setting available. When I use the TViX 16-235 setting, I don't see any h264 black level improvement with the tool. However, using 0-255 makes a startling improvement.

All that being said - I also see the Moome banding is minimized using 0-255. The banding is gone from some movies, and reduced in others. The "rope" scene white band example mentioned above is still there. I tried a Lumagen HDP with an Ophit DDA converter a few weeks ago and didn't see any banding issues at all with the same setup. Whatever I'm seeing is definitely in the Moome. I also seem to have a permanent white streak at the middle left side of screen. It disappears toward the center of the screen. It's always there at higher contrasts.

Color me confused about this whole 16-235 / 0-255 issue. For now, I'm going with 0-255!

Ray