AVS HD 709 - Blu-ray & MP4 Calibration - Page 135 - AVS Forum
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post #4021 of 4030 Old 08-28-2014, 11:45 AM - Thread Starter
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Originally Posted by sawfish View Post
I keep hearing about this levels round trip. Can anyone tell me how to demonstrate it? (I ask every time it comes up.) Is it just an AMD thing, or does it affect Nvidia and Intel, too?
I can only comment on my AMD card. Screen capture or the color cop progam can pull RGB values. The video and desktop will report as full-range, and that's the way the expansion setting has to be to stay in line with the 0-255 desktop. When the pixel format is set to the limited range it's clear that the pulled RGB values are not what's actually being output, and things are being put in the 16-235 range.

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In particular, if the end result preserves BTB and WTW, then the first leg of the round trip, the expansion from Video to PC Levels, is not losing this information, so if this is the case, it's not at all like actually outputting PC Levels, which loses this information.
I just tested, and Windows Media Player acts as if the full-range is being scaled back to the limited range, which means BTB and WTW are gone. I'm not sure what the DVD player I tried is doing, but the BTB and WTW are flashing. I would have to do a brightness comparison to guess and didn't have time.
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post #4022 of 4030 Old 08-28-2014, 01:00 PM
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I have not read through the post nor the thread yet. So Im sorry if this question is asked a million times. I dont have time to read everything RIGHT NOW so I thought Id ask and maybe someone can spare me some time.


Do I have to download and burn out these programs? Is it not possible to run them on my computer and through a HDMI cabel to my TV calibrate?
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post #4023 of 4030 Old 08-28-2014, 03:12 PM - Thread Starter
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Originally Posted by geearf View Post
As far as I know it's the same as the limited range, it's not available (yet?) :/
The only way I'm aware of to get a limited output for video and the desktop with an AMD card is to leave the video dynamic range on full and switch the pixel format to limited. The screens of those settings are shown at the following link, but it's the reverse of what they're doing:
http://www.avforums.com/threads/the-...hread.1474013/

For whatever reason the drivers I'm running seem to ignore the pixel format setting after a while and return to the default, but if this happens it should be somewhat apparent, and it would show up on the basic settings test patterns. That may just be an issue with my computer. If I had a display that couldn't accept full-range, I would try switching the pixel format setting to limited and see if that worked.
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post #4024 of 4030 Old 08-28-2014, 03:16 PM - Thread Starter
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Originally Posted by fbgkimpan View Post
Is it not possible to run them on my computer and through a HDMI cabel to my TV calibrate?
The video can be played on a computer, but it depends on what you're intending to do if that makes much sense. It may or may not make sense to display the video with a computer. For people that want to watch Blu-ray movies from a disc player it generally makes sense to burn a disc.
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post #4025 of 4030 Old 08-28-2014, 08:01 PM
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Originally Posted by alluringreality View Post
I can only comment on my AMD card. Screen capture or the color cop progam can pull RGB values. The video and desktop will report as full-range, and that's the way the expansion setting has to be to stay in line with the 0-255 desktop. When the pixel format is set to the limited range it's clear that the pulled RGB values are not what's actually being output, and things are being put in the 16-235 range.

I just tested, and Windows Media Player acts as if the full-range is being scaled back to the limited range, which means BTB and WTW are gone. I'm not sure what the DVD player I tried is doing, but the BTB and WTW are flashing. I would have to do a brightness comparison to guess and didn't have time.
Interesting, thanks. The only way I can get desktop output of 16-235 and demonstrate a Video Levels round trip is by setting my Nvidia GT430 "Digital Color Format", AKA Pixel Format, to YCbCr444, which I don't do, as RGB works better with my TV per Spears and Munsil 2nd ed Color Space Evaluation pattern as played on my Sony S5100, and WMC and XBMC calibrate consistently with each other and the BD player when Nvidia is left at the default RGB. With Pixel Format RGB, the video card outputs 0-255, and Video Levels is in principle just passthrough. Further, I have no evidence that it isn't just passthrough in reality. I haven't measured any discrepancies between the BD player and WMC/XBMC, I haven't observed gradient anomalies in one that aren't present in the others, BTB and WTW are fully present and behave as they should when they would have been destroyed in the first leg of this hypothetical levels round trip, etc. The only way I can demonstrate a levels round trip is by using YCbCr444, which compresses all output to 16-235. So I stand by everything I've said about Nvidia cards, as long as one is using the default RGB instead of YCbCr444.

Here's a summary of what I just tried with Windows Media Center (WMC) and Windows Media Player (WMP) in Windows 8.1 x64:

AVS HD 709 Black Clipping played on Panasonic ST60 set to Video Levels, that is, "HDMI/DVI RGB Range" set to "Standard (16-235)"; Nvidia Control Panel at its defaults

Nvidia GT430 "Digital Color Format", AKA Pixel Format, set to RGB, the default, which is what I use

WMC: Video Levels output; the bars contain the pixel values they are labeled with. Pattern appears as it should, and BTB is revealed by turning up Brightness on the TV. This is what I would call "passthrough". This is what I use.

WMP: PC Levels output; the bars < 17 contain 0, 17 contains 1, and so forth. Black is crushed, and BTB has been eliminated. Brightness has to be cranked hugely on the TV to make bars 17 and above flash. This is just simple expansion of Video to PC Levels which would require the TV to be configured to PC Levels for correct viewing.

Nvidia Pixel Format set to YCbCr444, which I don't use, but otherwise the Nvidia Control Panel is at its defaults:

WMC: PC Levels output; the bars < 17 contain 0, 17 contains 1, and so forth. BTB has been eliminated, but bars 17 and above are flashing at my normal Brightness setting. Clearly, the video card is compressing to Video Levels after the PC Levels images are buffered and available to screenshots. This seems to be a "levels round trip", and it applies to all output, video and desktop, making it all "work" when the TV is set to Video Levels. That said, if you want video and desktop consistency, it would be better to use PC Levels for everything if possible, so at least the desktop would be passthrough.

WMP: Just like WMC here. (Note the difference between this and WMP-RGB. Both legs of the round trip are completed here.)

OK, that's it for the Pixel Format experiment. As for the Video section of the Nvidia Control Panel, where you can set the Video Dynamic Range to Limited or Full, it has no effect on the desktop, and I don't think it can contribute to a levels round trip. In any case, I leave the entire Video section at "With the video player settings" and get the results I've described in previous messages.

Last edited by sawfish; 08-28-2014 at 08:09 PM.
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post #4026 of 4030 Old 08-29-2014, 12:07 AM
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Quote:
Originally Posted by alluringreality View Post
The only way I'm aware of to get a limited output for video and the desktop with an AMD card is to leave the video dynamic range on full and switch the pixel format to limited. The screens of those settings are shown at the following link, but it's the reverse of what they're doing:
http://www.avforums.com/threads/the-...hread.1474013/

For whatever reason the drivers I'm running seem to ignore the pixel format setting after a while and return to the default, but if this happens it should be somewhat apparent, and it would show up on the basic settings test patterns. That may just be an issue with my computer. If I had a display that couldn't accept full-range, I would try switching the pixel format setting to limited and see if that worked.
Right but you're using the Catalyst drivers, whereas I'm using the Gallium3d ones, which don't offer that. Hopefully they will soon.
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post #4027 of 4030 Old 08-29-2014, 05:01 AM - Thread Starter
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Now I see that it was mentioned up the page. I have a tendency to skim posts if someone else replies and if I'm okay with the response.

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Originally Posted by geearf View Post
1- Correct. I pretty much need contrast to be minimum, and brightness to be maximum to see #17 . I cannot see 16 or lower.
(If that helps, I can barely see @234
Ideally adjacent bars should generally be difficult to see, so if you're using a computer or something else that cuts off the video range then 17 and 234 should be difficult to distinguish. There is an alternate description for brightness with the second pattern. The second pattern may or may not result in a different brightness setting than the first pattern, depending on how the display performs. The second description is more in line with the way the commercial discs suggest for setting brightness.

Last edited by alluringreality; 08-29-2014 at 05:13 AM.
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post #4028 of 4030 Old Yesterday, 05:40 PM
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Originally Posted by alluringreality View Post
Ideally adjacent bars should generally be difficult to see, so if you're using a computer or something else that cuts off the video range then 17 and 234 should be difficult to distinguish. There is an alternate description for brightness with the second pattern. The second pattern may or may not result in a different brightness setting than the first pattern, depending on how the display performs. The second description is more in line with the way the commercial discs suggest for setting brightness.
Got it, the 2nd pattern seems easier to use since it's mirrored, but maybe it's just my imagination.

Now what should I do if contrast doesn't matter on the 3rd pattern, ie any setting from 0 to 100 shows every blinking lane?
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post #4029 of 4030 Old Yesterday, 06:18 PM
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Quote:
Originally Posted by geearf View Post
Got it, the 2nd pattern seems easier to use since it's mirrored, but maybe it's just my imagination.

Now what should I do if contrast doesn't matter on the 3rd pattern, ie any setting from 0 to 100 shows every blinking lane?
contrast patterns are useful when you want to maximize the light output.
you look for subtle color shifts and when you lose detail between the levels.
the 3 color red green blue blinking pattern is useful to see which color runs out.
the 2 patterns give you an idea how far you can go and still maintain balance.
this info gives you a max light output and balance for your contrast setting.

seems some TVs calibrate better when the contrast is high just before clipping of colors
.other TVs may calibrate better at specific foot lambert which are well below the max .
it is good to know when the TV can't put out balance light.

Loving D65
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post #4030 of 4030 Old Yesterday, 10:08 PM - Thread Starter
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Now what should I do if contrast doesn't matter on the 3rd pattern, ie any setting from 0 to 100 shows every blinking lane?
I'm basically going to opt-out on this question, since someone familiar with the particular plasma display could probably give a more thorough answer on how they would approach the question. White level can be a little more subjective than black level, especially for plasma displays. Like mentioned in the prior reply, Misc Patterns A3 & A4 are basic checks on what is happening with color, mainly to make sure you are not going too high with contrast. Discoloration and eye fatigue are a couple subjective items mentioned in the manual, which again are simply recommendations to avoid going too high on contrast. With a meter to measure the screen a shade of white and brightness of white can have recommended targets, but setting contrast that way requires a meter. Without a meter it's possible that the display may not fail any of the given tests for white level, so I would tend to refer you to the main forum for discussions on plasma white level particulars, or to a discussion about your display model. While it's a simple question, I'm simply going to suggest that someone else could address the question more thoroughly for plasma than I can. There may be a range of acceptable settings, depending on which subjective course of action you choose to take. For example I've seen people recommend for plasma to start at a low setting and turn up contrast to a level that you personally consider white reasonably bright, and so if you use that sort of method the answer will completely depend on the person doing the adjustment.

Last edited by alluringreality; Yesterday at 10:22 PM.
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