Hardware Pattern Generators vs. Blu-Ray Disk Patterns Comparison - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 51 Old 07-27-2013, 01:58 PM - Thread Starter
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I'm opening this topic for Hardware Pattern Generators Users, like Lumagen/Accupel/Quantum Data/VideoForge, that are curious to see what's the difference of the patterns that are generated from their External Hardware Generators vs. their Actual Blu-Ray Player using a Pattern Disk.

For anyone who want to test this to his system, please check the following things to help all data's that will be collected to be valid & uniform:

1) Be sure that the Color Space Output is the same to both Blu-Ray Player / External Pattern Generator.

2) Use the Same Settings / Same HDMI Input of your Display / Projector. You don't need to have this input you will measure calibrated.

3) Use Only Full Field Patterns without Labels (including Plasma users also) Because Window Patterns will not match exactly at their size between disks/pattern generators. (Plasma Displays are not reallt recommended for this test.)

4) Disable all Display's Enhancements before measuring.

5) Reset to Unity if you are using a Lumagen/eeColor in Chain. Disable Darbee Processing also.

6) Use only unprofilled colorimeter, not a spectro, we don't care about the dE your display have, we care only with the dE Differencies that the 2 patterns sources will have.

7) Run a 21-Step Grayscale, 4-Step Luminance & 4-Step Saturation with ChromaPure or 5/10-Step Saturation/Luninance with CalMAN.

8) Use only Pattern Disks that are it's encoding is based to Each Software Engine Targets. For Example Don't use AVSHD Disk Pattern for this Test, not because the disk has any problem, it's patterns are 100% accurate, but they have as slight difference between the targets the software solutions are generating with external pattern generators.

Ofcourse the disk can be used for any Calibrations using ChromaPure or CalMAN but not be used for this test because the AVSHD Patterns RGB Triplets are +1 -1 Level different from each software calculation engine. Color Gamut 100% Saturation with 75%/100% Can be used becasue they have the same RGB Triplet Levels. 4-Saturation Patterns have bigger differencies and it's not recommended for this test.

A Quick Example of Grayscale Patches of AVSHD Disk vs. CalMAN/ChromaPure Targets is here:



AGAIN: This difference in Grayscale Levels will show only differencies when you will compare a Pattern Generator with a Disk Pattern Source. No difference if you are using the AVSHD Disk for Display Calibrations.
AVSHD Disk has been tested with Waveform Monitors or by extracting the Original Pattern Files form it's Video Files and has none problem to any pattern. 100% Accurate.

If the other disk creators are reading this, please confirm which targets you used at your disks, to help us out selecting the correct disk for each Measuring Software.
Mid-Next Months I will release my LightSpace Calibration Disk that will have Patterns Based to ChromaPure + CalMAN Calculation Engines, but it will have only Large Window 11,11% ''Lumagen Size'' Patterns without Labels, so it will be usefull only for Lumagen Radiance Comparison.

The User Posted Test Results will help by creating a Database of Blu-Ray Players with their difference with various external pattern generator, by helping users to decide if they will be use a Disk or an Enternal Pattern Generatar for it's future calibrations.
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post #2 of 51 Old 08-08-2013, 01:03 AM
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Good post. To add some math to this:

The correct level for 5% would be (235 - 16) * 5 / 100 + 16 = 26.95. So obviously CalMAN and ChromaPure round the calculated level, while AVSHD truncates it. In comparison the madVR test pattern generator uses dithering to actually show 26.95. So we have 3 different approaches here.

In real life nothing of this matters, if (and only if !!) the calibration software knows exactly which level is being measured. I suppose both CalMAN and ChromaPure know that they are measuring 8bit value 27 and not 26.95, so no problem there, as long as CalMAN and ChromaPure take into account that they're not actually measuring 5%, but instead 5.02283105%. However, the AVSHD disc is problematic, I think, because movies are not usually encoded by using truncating!!

Edit: Also, by using rounding you have a max error of 0.4999, but when using truncating you have a max error of 0.9999.
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post #3 of 51 Old 08-08-2013, 02:39 AM
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Pattern disc for Blu-Ray player and Chromapure : recommended is Mascior's pattern disc. See here.

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post #4 of 51 Old 08-08-2013, 02:55 AM - Thread Starter
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BTW with CalMAN Level Editor you can enter the above AVSHD Level Values to create a new 21-Step Grayscale.
So after doing this, your Grayscale steps will be bit-perfect and the calculations will be 100% correct too. wink.gif
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post #5 of 51 Old 08-08-2013, 09:00 AM
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Quote:
Originally Posted by madshi View Post

Good post. To add some math to this:

The correct level for 5% would be (235 - 16) * 5 / 100 + 16 = 26.95. So obviously CalMAN and ChromaPure round the calculated level, while AVSHD truncates it. In comparison the madVR test pattern generator uses dithering to actually show 26.95. So we have 3 different approaches here.

In real life nothing of this matters, if (and only if !!) the calibration software knows exactly which level is being measured. I suppose both CalMAN and ChromaPure know that they are measuring 8bit value 27 and not 26.95, so no problem there, as long as CalMAN and ChromaPure take into account that they're not actually measuring 5%, but instead 5.02283105%. However, the AVSHD disc is problematic, I think, because movies are not usually encoded by using truncating!!

Edit: Also, by using rounding you have a max error of 0.4999, but when using truncating you have a max error of 0.9999.

what approach does the Spears and Munsil 2nd Edition use?

UN46EH6030 Calibration/Settings
Display: Samsung UN46EH6030 LED-LCD TV; Audio: Yamaha HTR-3066 AVR/AMP, Sony Core Bookshelves (Sony SS-CS5) and Center (Sony SS-CS8) as fronts, Cambridge Audio S20 Bookshelves (CA S20-N) as surrounds, Dayton Audio SUB-1200 as subwoofer; Sources: PS4 (doubles as primary BD player), Xbox One, PS3, Xbox 360, Motorola RNG150N (Cable Box)
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post #6 of 51 Old 08-09-2013, 09:25 PM
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My disc was created using the round nearest method or for software that assumes integer percentages.

 

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post #7 of 51 Unread 06-04-2015, 12:41 PM
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Gonna bump this..

Just recently picked up CALMAN Expert (cost me roughly 2 grand) and got myself a i1Display 3 (i1 Display Pro).

What calibration disk do I use for CALMAN? ChromaPure?
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post #8 of 51 Unread 06-04-2015, 01:00 PM
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Quote:
Originally Posted by HDMIOpticalNess View Post
Gonna bump this..

Just recently picked up CALMAN Expert (cost me roughly 2 grand) and got myself a i1Display 3 (i1 Display Pro).

What calibration disk do I use for CALMAN? ChromaPure?
Hi,

Just have a look there : http://www.displaycalibrations.com/m...solutions.html
...and you'll find all what you need (and more!) and have dreamed for... simply the best calibration disk
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post #9 of 51 Unread 06-04-2015, 01:28 PM
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To give a different perspective, here is what ISF states about the subject. This is from their Level 2 presentation.
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post #10 of 51 Unread 06-04-2015, 01:40 PM
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Ted's Disk is just the only one disc that covers both software solutions (CalMAN +ChromaPure) the same time.

Any other disk is compatible with one software and not 100% accurate for the other.

Also Ted's disk follows the same pattern order per software solution
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post #11 of 51 Unread 06-04-2015, 02:29 PM
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Quote:
Originally Posted by HDMIOpticalNess View Post
Gonna bump this..

Just recently picked up CALMAN Expert (cost me roughly 2 grand) and got myself a i1Display 3 (i1 Display Pro).

What calibration disk do I use for CALMAN? ChromaPure?
My recommendation is in my Sig.
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#1 Calibration Disk / Best Support: Ted's LightSpace CMS Calibration Disk
#1 Calibration Software / Best Support: LightSpace CMS - Calibration Comparison
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post #12 of 51 Unread 06-04-2015, 06:44 PM
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So..I still need a test disk...?

Some guy above is saying (randal_r) that some people in the slides say "YOU MUST USE A test generator!" as Blu-Rays are not ITU compliant...or some such

A lot of misinformation in this forum.
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post #13 of 51 Unread 06-04-2015, 08:53 PM
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Quote:
Originally Posted by HDMIOpticalNess View Post
Gonna bump this..

Just recently picked up CALMAN Expert (cost me roughly 2 grand) and got myself a i1Display 3 (i1 Display Pro).

What calibration disk do I use for CALMAN? ChromaPure?
wow, maybe calman will give you some help.
the grand i spent doesn't.

Loving D65
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post #14 of 51 Unread 06-04-2015, 10:08 PM
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I've been using ChromaPure for years and CalMAN from now, and i have never read anything like this about... Any recommandation from those 2 reputable software to not use discs

Tom Huffman from ChromaPure has runned that test at past:

The Official ChromaPure thread

Ask CalMAN
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post #15 of 51 Unread 06-05-2015, 06:59 AM
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Quote:
Originally Posted by HDMIOpticalNess View Post
So..I still need a test disk...?

Some guy above is saying (randal_r) that some people in the slides say "YOU MUST USE A test generator!" as Blu-Rays are not ITU compliant...or some such

A lot of misinformation in this forum.
There is always two sides to a coin, as there is always two points of view to a question. Many times on the forums, such as this one, people express their emotions more than facts. Hence the statement, "A lot of misinformation in this forum". The attachments that I forwarded are the expressions of facts from one of the groups that are experts in this area. If you take the THX course you will find that their sentiments reflect the same. This opinion is not exclusive to just these two organizations, others such as Joe Kane would also recommend a dedicated video generator.

The reason test discs exist is that it is an economical medium in which to offer a service and/or product. Test disc are fine but what the attachments were trying to convey was that the DVD players could be a weak link and could be highly questionable as a reference source. This does not mean they are worthless, on the contrary, they can be a very useful tool. I use the AccuPel 5000 Pro video generator but I own numerous test discs and find each one has something to offer. For the hobbyist they are an excellent alternative to a video generator. Although the WOW, Spears & Munsil test discs, to mention a few, do the job in which that were intended for but there are those who seek test discs for a particular need. The needs for these individuals are to compliment a particular piece of software that they use. The two main test dics that come to mind are AVSHD and Ted's LightSpace CMS Calibration Dics. Both are excellent product and I am not qualified to say which is better, so I recommend that you get them both and decide for yourselves. There has been a lot of work put into these test disc but they are not intended for those who seek to just adjust the Brightness or Contrast of their TVs.

Are video generators better or are test disc's? Make your own decision.
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post #16 of 51 Unread 06-05-2015, 12:53 PM
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The advantages of a test pattern generator are two-fold.

First, you can be (or at least you should be) certain that the pattern is of reference quality. Most disc based patterns are fine but occasionally disc players output less than reference values. Chris Heinonnen (sp?) did an article for Secrets of Home Theater several years ago looking into this, and he found that most of the players were fine, but a few weren't.

Second, the main advantage of a generator is ease-of-use. Once you have calibrated using a tool that automatically generates the test patterns you need you'll never go back to using discs. They are just too tedious and time consuming.

There are also two advantages to discs.

First, they include in the calibration workflow the entire video chain. However, as I said above most players are fine, so they generally don't add or subtract anything from the signal.

Second, is obviously cost. If you already have a disc player then calibration discs are a very inexpensive way to get test patterns.

There is also a third option, which is test patterns generated from the computer's video card that the calibration software provides. This has the potential to provide the best of both of the previous options: fast automatic pattern generation and no additional cost. There is one serious drawback to using internally generated test patterns: getting video-level (rather than PC-level) signals ranges from the challenging to the impossible depending on the video card.

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post #17 of 51 Unread 06-05-2015, 02:18 PM
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Quote:
Originally Posted by TomHuffman View Post
There is also a third option, which is test patterns generated from the computer's video card that the calibration software provides. This has the potential to provide the best of both of the previous options: fast automatic pattern generation and no additional cost. There is one serious drawback to using internally generated test patterns: getting video-level (rather than PC-level) signals ranges from the challenging to the impossible depending on the video card.
It used to be difficult. But it's not, anymore, with all the usual GPUs from NVidia, AMD and Intel. You just need to force the GPU driver to output PC levels (newer NVidia and AMD drivers have an option for that, for Intel there are tools available to force PC output levels), and then you need to use a test pattern generator which you can switch between PC and TV levels output. Many users are using madTPG as an automated test pattern generator with ArgyllCMS, HCFR, Calman and LightSpace and have no problems outputting either TV or PC levels, whatever they prefer/need. At least that's the feedback I received so far from many calibration users and developers.

The one big problem with HTPCs in general is that you can never be 100% sure that the GPU driver isn't doing something funny behind your back, like skin tone "optimization", dynamic contrast enhancement etc. But if you disable all those bad algos in the GPU control panel, the output is usually fine. This is the key advantage of standalone hardware test pattern generators: No stupid GPU drivers that can screw things up behind your back. So standalone hardware test pattern generators are the safer bet. A properly configured HTPC should work just fine, too, though.
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post #18 of 51 Unread 06-05-2015, 02:22 PM
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Also too, Graeme has implemented a nice dithered test pattern generator for the Chromecast device.
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post #19 of 51 Unread 06-05-2015, 02:40 PM
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Quote:
Originally Posted by madshi View Post
It used to be difficult. But it's not, anymore, with all the usual GPUs from NVidia, AMD and Intel. You just need to force the GPU driver to output PC levels (newer NVidia and AMD drivers have an option for that, for Intel there are tools available to force PC output levels), and then you need to use a test pattern generator which you can switch between PC and TV levels output. Many users are using madTPG as an automated test pattern generator with ArgyllCMS, HCFR, Calman and LightSpace and have no problems outputting either TV or PC levels, whatever they prefer/need. At least that's the feedback I received so far from many calibration users and developers.

The one big problem with HTPCs in general is that you can never be 100% sure that the GPU driver isn't doing something funny behind your back, like skin tone "optimization", dynamic contrast enhancement etc. But if you disable all those bad algos in the GPU control panel, the output is usually fine. This is the key advantage of standalone hardware test pattern generators: No stupid GPU drivers that can screw things up behind your back. So standalone hardware test pattern generators are the safer bet. A properly configured HTPC should work just fine, too, though.
Please provide specific step-by-step instructions on how this is done. I have never been able to get this to work on my laptops.

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post #20 of 51 Unread 06-05-2015, 02:51 PM
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Quote:
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Please provide specific step-by-step instructions on how this is done. I have never been able to get this to work on my laptops.
Step-by-step instructions for what exactly? For forcing the GPU to output PC levels?

1) AMD: The GPU control panel should have an option for that.
2) NVidia: Newer drivers should also have an option for that.
3) Intel: Not sure if the latest drivers have an option or not. Maybe not.

For NVidia and Intel, if your driver doesn't offer to output PC levels, use the "madLevelsTweaker" tool shipping with madVR. This tool will install a little registry tweak for either NVidia or Intel GPUs to force PC levels output. Then reboot and it should be working. Please note that you need to move the madLevelsTweaker window to the monitor which you want to tweak. The tool doesn't tweak all monitors in a multi-monitor setup, but just the one its main window is placed on, in the moment when you press the "apply" button.
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Quote:
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Step-by-step instructions for what exactly? For forcing the GPU to output PC levels?

1) AMD: The GPU control panel should have an option for that.
2) NVidia: Newer drivers should also have an option for that.
3) Intel: Not sure if the latest drivers have an option or not. Maybe not.

For NVidia and Intel, if your driver doesn't offer to output PC levels, use the "madLevelsTweaker" tool shipping with madVR. This tool will install a little registry tweak for either NVidia or Intel GPUs to force PC levels output. Then reboot and it should be working. Please note that you need to move the madLevelsTweaker window to the monitor which you want to tweak. The tool doesn't tweak all monitors in a multi-monitor setup, but just the one its main window is placed on, in the moment when you press the "apply" button.
The problem is not being able to output PC levels. It is the reverse. I cannot get my laptops to output anything but PC levels. You need video levels 16-235.

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post #22 of 51 Unread 06-05-2015, 04:49 PM
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Quote:
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The problem is not being able to output PC levels. It is the reverse. I cannot get my laptops to output anything but PC levels. You need video levels 16-235.
The rendering software does that.
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post #23 of 51 Unread 06-05-2015, 04:55 PM
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The rendering software does that.
The User Guide for MadVR says:
"Typically if you need to send 16–235 to a display, you will use the video card output to set that, not the video renderer."

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I'm not sure why it recommends that since that would mean scaling in the video card. When a video card is "forced" to 0-255 over HDMI that just means it leaves levels sent to it untouched, which is it's normal mode, and the software should send black at 16 and white at 235 to a display set for video levels. That's how CalMAN, HCFR and MadTPG generators work when video levels are selected within each software set-up.
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Thank you

With that being said - I still don't understand this.

Tom - what if one doesn't use a Blu-Ray disc - but rather just uses a DLNA solution to stream these test patterns (using purchased MKVs) or rather some external HDD hooked up to the TV directly. Then what's the issue? It's not a disk..so blu-ray device output is not an issue...?
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post #26 of 51 Unread 06-05-2015, 05:15 PM
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Quote:
Originally Posted by HDMIOpticalNess View Post
Tom - what if one doesn't use a Blu-Ray disc - but rather just uses a DLNA solution to stream these test patterns (using purchased MKVs) or rather some external HDD hooked up to the TV directly. Then what's the issue? It's not a disk..so blu-ray device output is not an issue...?
I did not claim that there was any issue with using media players to send images to the display. I was referring specifically to video cards in a PC. I don't have any experience with using media players in this way so I cannot comment on it intelligently one way or another.

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A lot of these test disk people sell their disks in MKV/MP4 format. I would like to know if one streams it directly from a hard drive on the TV - what differences there are if any. This avoids Blu-Ray nonsense altogether from the mix or PC video card output.
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post #28 of 51 Unread 06-06-2015, 12:34 AM
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Originally Posted by TomHuffman View Post
The User Guide for MadVR says:
"Typically if you need to send 16–235 to a display, you will use the video card output to set that, not the video renderer."
There are many different user guides for madVR, and I've written none of them. I disagree with what this user guide says here.

zoyd already explained, but I'll try in more detail:

I usually do not recommend to set the video card to output TV levels. Why? Because if you configure the GPU that way, basically what happens is that all the rendering (by desktop, games, applications, test pattern generators, media players) is still done in PC levels. But after all is said and done, the GPU driver takes the final rendering results and compresses them into TV levels, behind the back of the OS and all the applications. And the GPU drivers used to do this in 8bit without dithering, introducing rounding/banding errors. Some newer driver versions may do this in a higher bitdepth if the display supports DeepColor, I'm not sure, but I still don't like the whole concept of the GPU driver manipulating my rendering output behind my back.

My recommendation for best quality test pattern generation and video playback is to always set the GPU to PC levels. Which practically means that the GPU passes the Windows rendering results through to the display more or less untouched. Now the video renderer or test pattern generator has full control: It can output black as either 0 or 16, just as the user selects.

The next question to discuss is whether to set the display to PC or TV levels. Both is possibe, you'd just need to switch the media player / test pattern generator to the same setting. I usually recommend to set everything to PC levels, so that desktop, games and applications have correct black/white levels, too. Some displays don't properly support PC levels, though. For such displays I'd still recommend to set the GPU to PC levels, but the media player / test pattern generator to TV levels. Configured this way you should get perfect results from media players and test pattern generators - but desktop, games and application will lose shadow/highlight detail because the black/white level doesn't match. So there's this one situation where I reluctantly "allow" the GPU to be set to TV levels: If the display doesn't support PC level input, *and* if the user absolutely requires desktop, games and applications to have proper black/white levels, too, then setting the GPU to TV levels is the only option.

Hope this all makes sense to you?
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post #29 of 51 Unread 06-06-2015, 04:09 AM
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Originally Posted by madshi View Post
There are many different user guides for madVR, and I've written none of them. I disagree with what this user guide says here.
Now that you've explained how to setup your computer to work with madVR, I'd like to try it with Calman.

Given that there is bad information on how to use madVR, can you link us to a set of instructions on how to install it for a Calman implementation that's correct for a built in Intel HD video?

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post #30 of 51 Unread 06-06-2015, 05:10 AM
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Originally Posted by JimP View Post
Now that you've explained how to setup your computer to work with madVR, I'd like to try it with Calman.

Given that there is bad information on how to use madVR, can you link us to a set of instructions on how to install it for a Calman implementation that's correct for a built in Intel HD video?
Well, most tips are already in my previous post(s): Force the GPU to output PC levels, then switch both madVR and your display to PC levels, if your display can handle that properly. If not, set both madVR and your display to TV levels. Also turn off all the fancy "enhancement" algorithms in your GPU control panel. Then use some calibration test videos/patterns to make sure that black and white level are set correctly. Then you should be good to go.
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