"High Definition Benchmark" BD Edition by Stacey Spears and Don Munsil - Page 27 - AVS Forum
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post #781 of 1210 Old 12-17-2010, 11:24 PM
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Quote:
Originally Posted by sspears View Post

Contrast For Dummies: "Turn the contrast control up as high as you can without clipping any of the boxes along the bottom of the Contrast pattern."

That is as simple as I can describe it. There are a lot of gotchas, which is why we have written the full Setting Contrast article.

Thanks. I've read that article numerous times. When I follow the above instructions, I come up with 8 for contrast(but the boxes look pinkish). Then I reduced contrast to where the boxes look gray, and it was (-6). This is the setting I'm using. The clipping test shows red clipping, and to get rid of it, I need to reduce contrast to (-6).
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post #782 of 1210 Old 12-18-2010, 05:34 AM
 
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Mr Spears,
Thanks for the reply.I'll have to look elsewhere.
ps,
You sure Japanese DVD players use PC(0 IRE)and not Video(7.5 IRE).I have a Japanese DVD player.Its mpeg decoder chip uses Video levels(SDI allows access).I don't know about its analog port.
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post #783 of 1210 Old 12-18-2010, 09:07 AM
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You sure Japanese DVD players use PC(0 IRE)and not Video(7.5 IRE).I have a Japanese DVD player.Its mpeg decoder chip uses Video levels(SDI allows access).I don't know about its analog port.

PC and Video levels have nothing to do with 0 IRE and 7.5 IRE. PC levels have black at digital level 0 instead of digital level 16. This is different than the "analog" output being at 0 IRE or 7.5 IRE.

Quote:


This is the setting I'm using. The clipping test shows red clipping, and to get rid of it, I need to reduce contrast to (-6).

Its possible a professional calibration (grayscale) might clean that up. A display often has an advanced menu that has RGB drive and gain controls. The drive controls are really brightness and the gain are really contrast. The grayscale, or white balance, may fix up the pinkish and correct one color being off so far from the others.

Brightness and contrast may interact. Then you adjust grayscale. Then you revisit brightness and contrast.
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post #784 of 1210 Old 12-18-2010, 09:16 AM
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Troglobite, here's a little synopsis of IRE: http://zone.ni.com/devzone/cda/tut/p/id/4750#toc4 The rest is left as an exercise for the reader.

larry

Opportunity is missed by most people because it is dressed in overalls and looks like work. -- Thomas Alva Edison
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post #785 of 1210 Old 12-18-2010, 01:41 PM
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You take that back...
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post #786 of 1210 Old 12-18-2010, 02:14 PM
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Mr. Spears is a woman

Not that I am aware of.
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post #787 of 1210 Old 12-18-2010, 02:39 PM
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Quote:
Originally Posted by sspears; View Post

Its possible a professional calibration (grayscale) might clean that up. A display often has an advanced menu that has RGB drive and gain controls. The drive controls are really brightness and the gain are really contrast. The grayscale, or white balance, may fix up the pinkish and correct one color being off so far from the others.
Brightness and contrast may interact. Then you adjust grayscale. Then you revisit brightness and contrast.

Thanks again. Yes, my DLP projector(Mits. HC3800) does have the "Color Management" feature, but I don't know how to adjust the settings. Can it be done with your disc? I do have your cal. disc. Where would I learn how to do the RGB contrast and brightness settings?
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post #788 of 1210 Old 12-18-2010, 03:10 PM
 
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Pooper,
I know how IRE works. I just use 0 for 0% since that's how my Lumagen does it for simplicity. So the device doesn't use up more gates on the FPGA it offsets automatically Video to 7.5 IRE and calls it IRE for digital and analog signals.
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post #789 of 1210 Old 12-18-2010, 03:18 PM
 
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But anyway. I guess I didn't get my question across correctly. DVD and Blu-ray use Video levels (digital 16 or analog IRE 7.5) for 0%? Therefore the mpeg decoder itself even on Japan DVD player is Video digital 16 before conversion?
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post #790 of 1210 Old 12-18-2010, 03:27 PM
 
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If a disc that my Lumagen tells me has a full field of 0% using Video levels of digtal 16 or analog IRE 7.5. That same disc put in a blu-ray player would be the same? Video levels on DVD work exactly the same on blu-ray too? That's what Mr Wiggles told me
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post #791 of 1210 Old 12-18-2010, 04:15 PM
 
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If what I say isn't true why for the Radiance which has gates to spare Lumagen says:
"You can specify the black pedestal as RGB-PC level (0 IRE) or RGB-Video level (IRE 7.5).
Why would Lumagen make such a mistake like that?
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post #792 of 1210 Old 12-18-2010, 04:36 PM
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Quote:
DVD and Blu-ray use Video levels (digital 16 or analog IRE 7.5) for 0%?

I believe you are misunderstanding. Digital 16 is can be either 0% IRE or 7.5% IRE on the analog output. Both 0% and 7.5% are assigned to the digital code value 16.

Quote:
Video levels on DVD work exactly the same on blu-ray too?

HD does not have a concept of Setup like DVD does. However, we have seen devices that add setup to HD.
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post #793 of 1210 Old 12-18-2010, 04:38 PM
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Quote:
does have the "Color Management" feature, but I don't know how to adjust the settings.

Both CMS, and grayscale, can only be adjusted using a meter. Products like CalMAN have built some automated methods using the meter some certain video processors, and displays.

For our current disc we only included patterns that can be used without a meter.
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post #794 of 1210 Old 12-18-2010, 05:20 PM
 
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Mr Spears,
Apparantly I am.
So I tested what you said with my Japan DVD player using component. In default mode it was too bright and clipping darks/highlights. Then I did 'DVD video mode'. Worked perfect.
So I need to call Lumagen to disable/enable 'setup
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post #795 of 1210 Old 12-18-2010, 09:29 PM
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Quote:
Originally Posted by sspears View Post

Both CMS, and grayscale, can only be adjusted using a meter. Products like CalMAN have built some automated methods using the meter some certain video processors, and displays.

For our current disc we only included patterns that can be used without a meter.

OK. Someone told me I could adjust the RGB contrast and brightness with your disc and colored filters. I guess that's wrong then?
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post #796 of 1210 Old 12-18-2010, 09:42 PM
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I guess that's wrong then?

If you want them set correctly you must use a quality meter. This is not something that can be set by eye.
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post #797 of 1210 Old 12-28-2010, 10:50 AM
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Would this be the most correct way to adjust the brightness with the PLUGE Low pattern?
1. Of course, make the 2 BTB bars on the left dissapear.
2. Lower the brightness until the checkerboard JUST becomes invisible - and then bump it up until you can just barely see the checkerboard?

This is what I have been doing and it seems to be correct.
The checkerboard seems to give me more assurance that I am not still clipping blacks that I need because I can still see both bars on the right BEFORE (maybe a click) I can see the checkerboard, which is 16 and 17 together.
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post #798 of 1210 Old 12-28-2010, 11:52 AM
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Quote:


2. Lower the brightness until the checkerboard JUST becomes invisible - and then bump it up until you can just barely see the checkerboard?

It should barely be visible from your viewing position.

If it is easy to see from your viewing position, it probably means gamma is coming out of black too fast. e.g. 2.2 gamma will produce a brighter checker at your viewing position than 2.35 or 2.4, which is what we consider the correct display gamma for viewing movies in a light controlled room.

2.2. is great for sports, news broadcasts, or if you have a lot of ambient light.
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post #799 of 1210 Old 12-31-2010, 11:25 AM
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Hello all. Sorry for this noob question which may have been answered elsewhere. Will the S&M (ha!) Blu-ray be available for order again around January 7 2011 (the OPPS site says 2010)?
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post #800 of 1210 Old 12-31-2010, 02:49 PM
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New stock is expected next week. The blue filter is the major hold-up.
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post #801 of 1210 Old 12-31-2010, 03:09 PM
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In case you didn't know, you got a nice plug in the NY Times
http://www.nytimes.com/2010/12/30/te...ology&emc=ctb2
I'll order one as soon as you have them available.

Larry

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post #802 of 1210 Old 12-31-2010, 05:27 PM
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Quote:
Originally Posted by sspears View Post

New stock is expected next week. The blue filter is the major hold-up.

Great, thanks for the update! I look forward to receiving my disc in the new year...
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post #803 of 1210 Old 12-31-2010, 07:28 PM
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Hi Larry,

Not the best time to run out of discs.
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post #804 of 1210 Old 12-31-2010, 07:59 PM
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Quote:
Originally Posted by sspears View Post


Not the best time to run out of discs.

I could imagine

Well, I have some patience Keep us posted on your schedule.

I wouldn't have known about your disc if it weren't for the NY Times mention. And then I immediately came here to AVS to see what the pros here had to say. That's how I found this thread.

Larry

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post #805 of 1210 Old 01-04-2011, 11:19 AM
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Hi,
Wondering if I could get a bit of advice on color clipping. First, though, I just want to say thanks for producing this calibration disc! It has helped a lot, and I've learned a lot by using it and reading the articles on your site.

This is on a Samsung PN50C8000 plasma display, with a Samsung blu-ray player (no AVR between).

I've been able to get the contrast, brightness, color, and tint adjusted pretty well using the patterns. I used the display's "blue only" mode with the color bars pattern, and ended up adjusting color from 50 down to 46. But when I use the clipping pattern, I'm getting pretty substantial color clipping, especially in Red. I can bring it back by knocking the contrast and/or color down, but I need to lower them a lot.

Should I just live with some clipping, or is there something else I can do?

The display has color space settings (auto, native, custom). Native seems best - and is described as "wider than source". Auto looks pretty bad - more clipping, and hues seem off to me. I'm afraid I get over my head when I go into the custom menu, even after reading the article on choosing a color space.

Thanks for any advice.
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post #806 of 1210 Old 01-04-2011, 07:58 PM
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Should I just live with some clipping, or is there something else I can do?

Which picture mode are you using? It sounds like a color decoder error. Some displays, in cinema/movie, use the correct color decoder. In the other modes they are off by design. (manufacturer design)

What happens if you go through the full contrast range while looking at the clipping control?
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post #807 of 1210 Old 01-04-2011, 08:19 PM
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Quote:
Originally Posted by sspears View Post

Which picture mode are you using? It sounds like a color decoder error. Some displays, in cinema/movie, use the correct color decoder. In the other modes they are off by design. (manufacturer design)

What happens if you go through the full contrast range while looking at the clipping control?

Thanks for replying.

On this set, there are several pre-set modes (dynamic, standard, movie) and two (cal-day, cal-night) that have the full set of calibration options. I'm using cal-night. I could try it with movie to see if that makes a difference.

Contrast ranges from 0-100. Based on the contrast pattern, I came up with 90 (which is pretty close to CNET's 92). Dropping it down around 60 brought out all the concentric squares in the clipping pattern. Also, dropping color way down brought out all the concentric squares.

I've settled on a combination, where I lowered both contrast and color a small amount, and if I walk right up to the screen, I can see most of the concentric squares.

Maybe that's the best I can get without equipment? I have to say, the picture looks terrific, so I wouldn't be disappointed.
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post #808 of 1210 Old 01-05-2011, 10:29 AM
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Are the cal modes ISF modes? Has someone come and calibrated them yet? They might be using a good decoder in those modes. I would still compare to the movie mode. Once you switch modes, you should run through the basic calibration again because each mode often uses different settings as a starting point. They of each mode as a memory.

Does your display also have green and red only modes? I some of the newer models do. Once you set using blue only mode, it is easy enough to verify decoding by looking at green only mode.

I know, from experience, that the Samsung RP DLPs had incorrect decoder that could be fixed in the service menu. I am hoping that movie, or your cal modes, offer correct behavior by default.
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post #809 of 1210 Old 01-06-2011, 04:57 AM
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Yes, I think the cal modes are intended for ISF calibration, but I haven't had any professional calibration done. I ran through the calibration again with movie mode, and I got to roughly the same point. Results seem similar to me. FWIW, here are a few pictures (taking decent pictures of the TV was difficult - lots of noise in them). These were taken after I dropped contrast and color a few notches to reduce clipping, though you can see that there is still some clipping near the middle of the patterns.

Thanks again for the help, but I don't want to take too much of your time. I'm fine leaving it alone until/unless I get around to professional calibration.

Color bars with green only display:



Clipping pattern:


Close up of green clipping pattern:
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post #810 of 1210 Old 01-06-2011, 11:01 AM
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Quote:


Color bars with green only display:

Perfect, thank you. See how you can see four distinct bars on the left of the green color bars pattern? If the color decoder was working correctly, it would be one big green bar. (with a litte ringing between each bar) Assuming you have adjusted color and tint using blue only mode, then the color clipping problem is because of the color decoder.

I really wish all displays had green only mode. It makes it easier to debug.

Try this excersize. Start with each picture mode. Set color and tint, and then look at green only mode on the color bars. See if any mode result in the correct behavior.

It may be a case where a service menu adjustment is required to fix the decoder. This is, of course, assumging they still expose the options.
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