Bizarre Behavior HD131xe - AVS Forum
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post #1 of 12 Old 07-11-2014, 11:48 AM - Thread Starter
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Bizarre Behavior HD131xe

I'm not really sure of what to make of this behavior on my HD131xe. I have been playing around with a few different calibration settings to try and get the best skin tones possible. However, the behavior of the greyscale seems to be quite strange.

With my white set to -10, 4, -16, I see banding on the smooth gradient portion of the test pattern which I understand can occur with a digital projector, but I would have expected the bands to continually get darker or lighter on a gradient. What I am seeing here is going from left to right, a dark band, followed by a white band, followed by the gradient.

Further, on the portion of the test pattern that is supposed to be bands, if I increment the green up one notch to 5, the color of the 90% white band I believe (it is the third one in fein the left) changes dramatically from the more bluish tone you see here to a much more reddish tone. Nearly every other step that I noticed was generally smooth with minimal changes. It almost seemed like by making this one small change, the setting actually went up several notches.

Is this expected behavior, a bug in the firmware, or a product of pushing the settings where they are.

Thanks!
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post #2 of 12 Old 07-11-2014, 06:16 PM
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Are you adjusting white in CMS (with red/blue/green/cyan/yellow/magenta/white)? I don't remember if the 131 has a separate white balance somewhere else, but that one I just mentioned does NOT work well with extreme settings (over 5-8) and can do really odd things with negative numbers.

It will also work differently depending how high your contrast is set because certain color will run out of high-end and further increases won't do what you'd expect.
Because of the 131 (Optoma in general) way of doing "brilliantcolor", you'll run out of primary before you run out of white so you can end up with an abrupt drop-out of tint near the higher end where you'll have a warm/cool white up until a certain point where it just changes into a different tint for the rest of the way till peak.
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post #3 of 12 Old 07-11-2014, 06:19 PM
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Try lowering your contrast by a point or two and see if that fixes it. It shouldn't take more than a few and you'll have a smoother gradient with more consistent white-balance.

If that doesn't completely solve the issue, and you've done your adjustments in the white section of the color-management, try lowering/raising your white-cms numbers to a less extreme setting (closer to zero). And, if you can stand the drop in brightness, lower "brilliantcolor" to the lowest you can stand.

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post #4 of 12 Old 07-12-2014, 09:36 AM - Thread Starter
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Thanks, I will take a look at this tonight. I did try changing the contrast adjustment earlier and it really didn't make a difference in banding. I may try a more extreme adjustment on that later tonight when I am home.
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post #5 of 12 Old 07-12-2014, 07:10 PM
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The contrast and cms stuff mostly fixes the white-balance so it doesn't have the abrupt change from white-ish to blue-ish. Some banding problems might be from the gamma setting but that should only cause it for parts and not the entire gradient. I want to say film is most accurate and video is brightest gamma. Graphic is too extreme and I don't really remember the other.

Turning brilliantcolor low can help against banding and video-noise (static-y speckles). One is best if you can, but anything lower than four is usually better than nothing.
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post #6 of 12 Old 07-13-2014, 07:43 AM - Thread Starter
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Quote:
Originally Posted by Ftoast View Post
The contrast and cms stuff mostly fixes the white-balance so it doesn't have the abrupt change from white-ish to blue-ish. Some banding problems might be from the gamma setting but that should only cause it for parts and not the entire gradient. I want to say film is most accurate and video is brightest gamma. Graphic is too extreme and I don't really remember the other.

Turning brilliantcolor low can help against banding and video-noise (static-y speckles). One is best if you can, but anything lower than four is usually better than nothing.
Yeah, I generally like the way film looks. I did find that the only real way to eliminate the banding was by setting the contrast down to something like -25. I don't recall seeing the banding before, but perhaps this is the first time that I noticed it. I do have this banding at all CMS settings. I just thought it was weird to see dark bands after lighter bands. I may try the same pattern with another BD player, the same BD player with a shorter/better HDMI cable or also hook up my laptop to it and see how it responds (granted my BD player is YUV, but the laptop will be RGB). Does anyone else with a 131xe have the same issue?

The other thing I found was that on certain settings there is an overlap between the green and the magenta (however, when I look at test patterns on other displays such as my computer monitor, I notice the same thing).
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post #7 of 12 Old 07-13-2014, 02:17 PM
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Check the HD25e thread for posts by kenhd to get better color reproduction and skin tones. Haven' t noticed any major PQ issues with mine. Motion handling is far better than my Panny GT60. There is some noise on skin tones noticeable during close up shots which in my opinion is almost non- defeat able

Blu-ray : 340
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post #8 of 12 Old 07-13-2014, 06:18 PM
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Does the 131 and that player show banding or odd things during movies too or might it be a problem with how the player is handling that test disc?

I'd wonder if the disc has its gradient change by two's instead of one's which can cause visible banding until contrast is quite low. Having to turn contrast down to -25 shouldn't be necessary and I don't remember the 131 I tried having a particular problem with banding..but I was playing with a 6-7ft hdmi from a PC.

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post #9 of 12 Old 07-13-2014, 09:39 PM - Thread Starter
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So, I tried another BD player with a much shorter HDMI cable, still the same banding issue.

However, I also hooked my laptop up to the projector and started playing with photoshop. Granted I know it is a different color space, but it appears that depending on the settings, there are just some shades of grey that this projector treats differently.

The grays where the color gets weird change depending on the color settings, but I found that under my current settings (and whatever color profile my mac was putting out, who knows what that is), that R 248 G 248 B 248 had a noticeable blue cast where as R 247 G 247 B 247 and R 249 G 249 B 249 did not. (granted this is an RGB color space as opposed to YUV).

I found this particular point when I put a gradient on the screen, and then used the OSX digital color meter to see what color it was supposedly outputting at the point there was a darker band. Then I verified this behavior in Photoshop by creating overlayed bands stepping up by one from RGB 245, 245, 245 to RGB 249, 249, 249. The 248, 248, 248 band had a noticeable different color cast.

Also, for this, I had Briliant Color at 1 and Dynamic Black off. I wish I had an accurate meter to grab the color coming off of the screen, as I am not going to waste anyones time with whatever my cheap really old (and soon to be replaced, hopefully) Spyder 2 reads.
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post #10 of 12 Old 07-13-2014, 09:46 PM - Thread Starter
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Quote:
Originally Posted by Ftoast View Post
Does the 131 and that player show banding or odd things during movies too or might it be a problem with how the player is handling that test disc?
Really haven't noticed anything too odd with movies, but I have been using a temporary screen that has some wrinkles in it until I move and get a much better screen. So any oddities, I would discount to the wrinkles. (with that said, I did verify that the blue tint thing is not a factor of the wrinkles as I moved the projector and watched the slightly blue tinted band follow.)

I guess my concern is that the warranty on this is up in another month, and I want to be sure that it is performing up to specifications and there is not some part in there that is slowly dying that is causing this. I don't recall seeing this earlier, but I also was not as critical of the image back then. I do think I noticed the oddity where the entire color cast of a few bands (on a test pattern with the 5% incremental bands) would dramatically change tints just by incrementing the green by one step, when all the other increments were the very minor change you would expect.

I guess what I am secretly hoping for is that Optoma discovers that there is some bug in the firmware that is causing this, finds it, fixes it, and doing so gives us even more accurate calibrations. As I have a Mac, I did not update to the latest firmware yet as I need a PC, but my impression was that the C04 firmware did not address the CMS. Still working on finding a PC where I can run the .exe and upgrade to that firmware just in the event there are some undocumented changes.

Last edited by shamrock1213; 07-13-2014 at 09:50 PM. Reason: Forgot to add thought
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post #11 of 12 Old 07-14-2014, 09:50 AM
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Though I can't say for certain that I was on the same/latest firmware, the 131 that I bought a couple months ago did NOT seem to have this behavior of a single color showing tint while both adjacent didn't.

I'd get it exchanged if possible.
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post #12 of 12 Old 07-14-2014, 04:42 PM - Thread Starter
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So I upgraded the firmware, it seems as if the bluish tint to the band only happens on the left side of the screen.


Photo 1 and 2 are white boxes ranging from RGB 246,246,246 to 250,250,250

If you look at photo 1, you can definitely see a blue cast in the 248, 248, 248 box. Photo 2, however I moved the same image over to the right hand side of the screen and the blue cast most goes away.

In Photo 3, you can see the gradient with the banding, albeit it is a bit hard to see.
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