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AVS HD 709 - Blu-ray & MP4 Calibration - Page 71

post #2101 of 3881
Quote:
Originally Posted by Brian Hampton View Post

Wouldn't clipping white above 235 be a good plan?

I can actual get bars to flash in the white pattern to 255 but I figured clipping above white would present the correct response.

It turns out that disc authors have been using the above white area. I don't know when that started but it is apparently very common. It's ok to clip it; you may miss some details in the clouds.

Clipping below black is an easier choice. There may be a scattering of pixels below black but in general no valuable picture information.

-Bill
post #2102 of 3881
Quote:
Originally Posted by Brian Hampton View Post

Wouldn't clipping white above 235 be a good plan?

Almost certainly. See the Setting Contrast with Spears and Munsil thread but most above reference material found seems to be the result of compression without proper filtering.
post #2103 of 3881
Yeah,

I downloaded the disc yesterday and realized I can see lots of above white so I clipped it and thought the image looked better afterwords. Seems there should be no need to produce things above white with the same care as you would provide things that are in what's supposed to be visable.
post #2104 of 3881
Thread Starter 
From what I've seen I would suggest that most likely you do NOT want to set contrast so high that the Basic Settings patterns here clip at 235. For displays that do allow contrast to go high enough that grayscale can clip near 235, I would still suggest probably setting contrast below that point. The following are the items I have seen that would suggest showing some grayscale higher than 235:

Drop in gamma - Some displays will notably fall-off in gamma near where they clip. The grayscale and color bars patterns can be used as a quick check of gamma as noted in my last thread reply, or gamma can be measured. Using a lower contrast than clipping at 235 may cause any gamma fall-off to be pushed into the above white region.

Color shift - Generally a display will color shift where it runs out of contrast, and the colors won't run out at exactly the same levels. For looking at color shift by eye the grayscale ramp can be used, or grayscale can be measured for a more thorough look at color shift. Using a lower contrast than grayscale clipping at 235 could again tend to push any color shift more into the above white area.

Red, Green, Blue Clipping - Generally colors will clip at slightly different levels. If gray appears to clip at 235, the colors will probably not all clip at 235. Like noted in the last thread reply there is a color clipping pattern in Misc Patterns to look at where the colors run out.

While I generally do agree with using a somewhat high contrast, I think the three above items are worth looking at for anyone considering clipping nearer to 235. If you don't want to go through the trouble of looking into these items, then the safe thing to do is to avoid setting contrast higher than where most all the above white bars (236-253) from the Basic Settings still flash.
post #2105 of 3881
Quote:
Originally Posted by Brian Hampton View Post

Yeah,

I downloaded the disc yesterday and realized I can see lots of above white so I clipped it and thought the image looked better afterwords. Seems there should be no need to produce things above white with the same care as you would provide things that are in what's supposed to be visable.

it will look better due to increase in contrast ratio.
post #2106 of 3881
Yeah,.... I did think it may look better just because there's more light output because I tend to be conservative with overall light output.

I think I may crank it back down a bit.

Or.... crank it back down and then turn off "SuperWhite" in the PS3 settings. Will this limit above white? May have to look into it.

-Brian
post #2107 of 3881
Quote:
Originally Posted by alluringreality View Post

From what I've seen I would suggest that most likely you do NOT want to set contrast so high that the Basic Settings patterns here clip at 235.

I may have been too flip. Assuming you have no problems setting contrast in the display to any convenient value then setting maximum output to reference increases your contrast ratio for free -- all things being equal. You do have to make sure all things are equal.
post #2108 of 3881
Quote:
Originally Posted by bodosom View Post

I may have been too flip. Assuming you have no problems setting contrast in the display to any convenient value then setting maximum output to reference increases your contrast ratio for free -- all things being equal. You do have to make sure all things are equal.

While that's true, it takes a pretty special television or method for controling the output to truley control that.

The PS3 outputs YCC for Blu-ray. Your TV displays in RGB 8bit space.

Many YCC values that are passed with superwhite off, still transform to RGB values over 235.

While very little content is effected either way, trying to calibrate for clipping at 235, can lead to very signfigant discoloration, which will subtly change your perception of an image.

How signifigant is any of this?
Not hugely, the extra little bit of light is of nominal value. The discoloration would be very slight as there are only a few pixels above white (Although in things like live sports broadcasts that may be different.).

But when faced with a choice, where sometimes the color WILL be wrong v reducing light output by 10-15%, I go with dropping light output. Charles Poynton recently commented on this stating that you should always allow the set to display all the way up to 254.
post #2109 of 3881
Ok.... For the record... I'll drop the Contast back to 90. It's the default and I can see the flashing stuff all the way to 255 or 254 (pj isn't on at the moment.)

I can't say I really saw "noise" in bright stuff. (I certainly have seen noise in the low end but that must be common with compresion and maybe it's just easier to spot on the low end.)

I won't miss the light output... I run a very small screen and it's plenty bright. Plus, I don't have any TV's. If I had a direct view LCD TV somewhere in the house that I viewed regularly then that would likely make me want more light out of my pj just to the big gap in brightness in the two technologies.

Either way,.. I won't use DVE again to for Video. It's great but I like the AVSHD test patterns more.
post #2110 of 3881
This is my plasma clipping at 240. However I'm displaying full range on the hardware (all the way up to 254) and then (soft) clipping with a super secret CMS.

If I clip on the plasma (down to 235) I get a tiny bit of measurable blue runout .However its not visible in normal viewing.

I'm getting no problems in gamma by clipping at 240.

check out the gamut correction on the post lutted report!

 

06_12_10_postprofile.pdf 112.123046875k . file

 

06_12_10_preprofile.pdf 110.4326171875k . file
post #2111 of 3881
Hi!
TX for sharing!!!

But i want to know where i can find a tutorial who clearly explain how to use each pattern cuz i find that the attached pdf isn't clear.
With only visual calibration(no hardware)
post #2112 of 3881
Quote:
Originally Posted by sotti View Post

While that's true, it takes a pretty special television or method for controling the output to truley control that.

Doing a perfect job may be tricky or not. Any REON can be told to do colorspace conversion with a clipping window.
Quote:


The PS3 outputs YCC for Blu-ray.

Unless you select RGB which I believe clips to reference.

I would agree that doing it in the display may require a special purchase but I think it's quite commonly available in upstream devices.
post #2113 of 3881
Thank you soo much for this! great job making this happen. works excellent and didnt need to pay for it =).

Finished calibrating my panasonic. Now just hav to get a new blu-ray movie and enjoy =)
Thanks again!
post #2114 of 3881
Is there a means by which these test patterns can be (have been) converted to DVD such that all video levels from 0-255 are preserved including the detail between individual video levels ?

The purpose is to test black and white levels for DVD playback with software such as Arcsoft TMT under various scenarios.

I'm not interesed in attempting to preserve the HD resolution (1920x1080) in any such conversion, just the video levels.
post #2115 of 3881
Quote:
Originally Posted by drsmithdtv View Post

Is there a means by which these test patterns can be (have been) converted to DVD such that all video levels from 0-255 are preserved including the detail between individual video levels ?

.

All the popular test discs with the exception of Avia have level below 16 and above 235.

Certainly the AVSHD disc covers the full range.

You do realise that reference black and white are 16 and 235?
post #2116 of 3881
Thread Starter 
Quote:
Originally Posted by drsmithdtv View Post

The purpose is to test black and white levels for DVD playback with software such as Arcsoft TMT under various scenarios.

If you live in a big enough city the library may have Avia or Digital Video Essentials to rent for free, and online rentals such as Netflix may also have the newer Avia II. If you're willing to buy there is GetGray for download. I believe the DVD included in http://www.avsforum.com/avs-vb/showthread.php?t=852536 has some basic levels patterns, or there is http://www.avsforum.com/avs-vb/showt...7#post14044357 that links to the video that the black and white clipping patterns here were based on.
post #2117 of 3881
Thanks for the replies.

I actually found I had Merighi Test DVD on a dark, dim, distant part of a hard drive.

http://www.hwupgrade.it/forum/showthread.php?t=1643245
post #2118 of 3881
Hi all,

First of all, thanks to all the hard work that loads have put into Calibration understanding, patterns, tutroials etc etc, Great JOB!!!!!

Im having a little trouble choosing between the avchd or Mp4 or others.

i'll explain my setup, i have a Epson tw680, i want to eventually hook it up via dvi/hdmi to my htpc that has a built in Bluray disk player. I would also like to hook up my xbox 360 to the projector at some point with the help of a HDMI splitter (I HAVE NO HD-DSK PLAYER ON THE 360)

I have downloaded the HCFR software and have a Xrite Eye one display probe at hand.

which pattern package should i choose?, is there a difference between them? in relation to colour space, white balance (if that makes any sense). Can i calibrate for example using the Mp4 package and get the same results as if i used the hd version.

all/any help and/or tips would be much appreciated. thanks you all in advance and sorry if this question has already been posted, ive spent the past few days reading through different threads here and on the HCFR website but my understanding of it all is unfortunately very limited at the moment.

thanks.
Nige'
post #2119 of 3881
Quote:
Originally Posted by corrupt85 View Post

Im having a little trouble choosing between the avchd or Mp4 or others.

I have downloaded the HCFR software and have a Xrite Eye one display probe at hand.

which pattern package should i choose?, is there a difference between them?

I use an i1LT with the AVSHD version on a Blu-ray player, and use the patterns in the following Chapters for calibration:
- Contrast: 100% White
- Brightness: 10% Greyscale
- Greyscale: 10% Greyscale
- ACM(very subjective with an i1LT): 10% Greyscale and 100% White and 100% Cyan
post #2120 of 3881
Thread Starter 
Quote:
Originally Posted by corrupt85 View Post

i have a Epson tw680, i want to eventually hook it up via dvi/hdmi to my htpc that has a built in Bluray disk player.

Use whatever version is compatible with the Blu-ray player software. The list of Blu-ray players in the first post lists the major computer programs for Blu-ray playback.


Quote:


I would also like to hook up my xbox 360

The Xbox can play the mp4 version from DVD media after an online update.


Quote:


Can i calibrate for example using the Mp4 package and get the same results as if i used the hd version.

The video is encoded the same, so really this depends on the player or players. For example if you play Blu-ray with one computer program and play mp4 with another computer program it is possible that the different programs may not match, but it's also possible that they could match. With different players again they may not completely match, or they might match. If you're using multiple players, or multiple software programs (decoders), you can only be sure how they compare by testing each one.
post #2121 of 3881
thanks for the quick responses guys, but perhaps i didnt explain myslef properly in regards to the format of the patterns.

if i were to use the mp4 format of patterns (say it works) on my bluray, would it do the same job (calibration wise) as if i used the avshd format
post #2122 of 3881
yes
post #2123 of 3881
Thanks!!!!
post #2124 of 3881
Id like to contribute my part, even if this is an old post, therefore, I own a canon 500D, does anyone know of any settings to repoduce a photograph of what my displkay actaully looks like so i can post the pics here?
thanks again.
post #2125 of 3881
Quote:
Originally Posted by corrupt85 View Post

thanks for the quick responses guys, but perhaps i didnt explain myslef properly in regards to the format of the patterns.

if i were to use the mp4 format of patterns (say it works) on my bluray, would it do the same job (calibration wise) as if i used the avshd format

HTPC calibration is a little more complex as you have found.

The first thing you need to do is make a decision as to whether you want the PC to output "full range" video or PC level.

Full range gives video precedence and means that video is passed "unmolested". This is analogous to what a conventional "video" source does.

PC level gives priority to PC level imagery as a baseline and video material is accordingly often remapped to be consistent with this (16 mapped to 1 235 mapped to 254 usually).

What you pick is a personal preference but "video" level is usually preferred for ensuring complete transparency.

Its a bit of a minefield this as various drivers , hardware and playback software can all impact on this. Media centre for example assumes video level takes precedence but what does it then do with sRGB type images. Your display may also do some odd things to a PC type signal and remap it for video level assumption or vice versa (bit messy).

Assuming you can get all the nuts and bolts to behave the easiest method I've come up with is to use the Calman HTPC pattern generator to calibrate your display to video level (usually also do grayscale using this as a reference).

For TMT I then use the internal picture control to align the output to the video calibrated display using the AVSHD disc. TMT defaults to PC level assumption in terms of setup but luckily it doesn't clip the data so you can restore video levels without any obvious ill effects.
MPCHC behaves itself just fine using custom EVR presenter ( assuming you don't do any fiddling about).

For final metering I use MPCHC with the AVSHD material.


I also use John Adcocks Upsilon Mixer which is currently in beta (its what I used for the CMS control in the charts I've posted previously). This enforces correct video level output behaviour on the gpu and then automatically profiles and applies correctional LUTS ( to give the pretty much perfect results I posted) It also allows custom gamma and white point mapping as well as gamut correction and it changes targets appropriately for PAL/NTSC/HD colorspaces.

For white on the display I target 254 on the hardware and 240 on the HTPC (using the upsilon mixer and the internal controls for thins like overlay).

For other inputs I again target 240 on the display hardware. I do get a small runout in blue but its only noticeable on a chart rather than in normal viewing.
post #2126 of 3881
Quote:
Originally Posted by corrupt85 View Post

Id like to contribute my part, even if this is an old post, therefore, I own a canon 500D, does anyone know of any settings to repoduce a photograph of what my displkay actaully looks like so i can post the pics here?
thanks again.

People's camera's photographs of their screenshots posted here, regardless if they own state of the art, laboratory quality optics, are next to meaningless for a variety of factors:

-Your camera has a completely variable light sensitivity aka "ISO" (previously called ASA). Stating what setting you used still doesn't then convey your camera's absolute light sensitivity that's meanibgful to what we'd see.

-Your camera has a completely variable color temperature aka "white balance".

-Your camera lens has various geometric distortions simplistically described as "pincushion" and "barrel".

-Your camera has noise so it is impossible to know if noise we'd see, for example FPN, is from the camera or the display. [that's the gist of all these bullet points, actually]

-Your camera lens has slight softening and lack of precise focus in the corners.

-Your camera lens has a slight darkening of the image in the corners called vignetting.

-Your camera has a slight, variable chromatic aberration as one moves from the center of the image outward which on a video display could easily be misinterpreted as misconvergence.

-Your camera introduces artifacts to the image due to jpeg compression.

-Your camera inevitably has a different native resolution than your video display or our viewing monitor, so artifacts of scaling will be introduced.

-Transmission over the internet and the necessary file size reduction also introduces artifacts.

-Viewing your image on a monitor without a way to calibrate the incoming image's gamma to the display's gamma makes grey scale and brightness tracking impossible to judge.

This is just a partial list, but in a nutshell it would be impossible for us to know if aspects and artifacts of the image we'd see were due to the camera, lens, compression, our own monitor's imperfections, and internet transmission, or if they were representative of the actual image you see with your own eyes in person. Bringing images of your screen you've photographed yourself, despite your nice camera, won't in any real way convey to anyone in this thread what you are actually experiencing with your own eyes in person, and that's why this 2000+ post thread has no screenshots yet many if not the majority of us own nice cameras too. Thanks for the offer though.
post #2127 of 3881
if he has a 500D he probably already knows all that.

And the vast majority of those problems can be overcome pretty easily.
ISO100+Tripod
easy to set WB
geometric distortion easily fixed w/ ptlens
ISO100+Tripod
close up the aperture a tad
increase the focal length just a tad
not much can do about this one(though ptlens can help) I doubt we'd see this on the tiny photo that's required to represent 1080p though
shoot raw
dunno what artifacts of downsizing a photo would give
dropbox
we all need calibrated monitors
post #2128 of 3881
I am assuming the patched is best for ps3 slim, if one doesn't have a blu-ray burner.

Does the ps3 slim upscale this, or is this in blu-ray format?
post #2129 of 3881
Thread Starter 
Quote:
Originally Posted by ps24eva View Post

Does the ps3 slim upscale this, or is this in blu-ray format?

The patched version is the Blu-ray with a change so that some players will identify it as AVCHD. The PS3 is a player that will not play HDMV from DVD media, but it can play the same video from DVD media after the AVCHD patch is applied. All versions include 1080p video, which is the highest resolution that Blu-ray or AVCHD currently support.
post #2130 of 3881
On Basic Pattern 3 - White clipping Pattern; while I am altering the contrast, I am supposed to see the flashing bars below 235 start to disappear. But they aren't. They do get darker/brighter but they remain there as plain as ever from setting 0 to setting 100.

What am I missing?
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