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Old September 20th, 2010, 05:55 AM   #1
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The Color Black in Video playback - why isn't it really black?!

Hey Guys,

i am working on a pc menu right now that uses a motion background (much like in a dvd menu) - the thing is: the background that should be black really isn't. I've noticed this many times before. As soon as i play a video clip (especially in WMV Codec) on a pc, the color black somehow gets 'upgraded' to a very dark gray.

I don't know how to describe this properly so I really hope you guys have experienced the same thing.

Is there a cure for this?

Thanks!
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Old September 20th, 2010, 07:50 AM   #2
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How black your black is depends on your display device and how dark the surrounding environment is. Ensuring that you've correctly set up your monitor and are sitting in subdued lighting is the way for best results.

Blacks tend to look blacker if you've got a bright reference in the same frame eg white title letters against a black background.
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Old September 20th, 2010, 08:21 AM   #3
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:D i know that - this is not an issue with my monitor. Black in Photoshop is actually black. Black in Premiere is black. But when i playback the video with black in it, it's gray :(

here's an example
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Old September 20th, 2010, 01:13 PM   #4
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For technical reasons, broadcast standards for blacks and whites were not 100% black and white, whereas computer graphics are 100% black and white. This is probably the cause of the difference you are seeing. Somewhere the program is probably adjusting your black level to appropriate broadcast levels for you.

Here's a link that talks about this: Technique: Black & White vs. Super-Black & Super-White

Here's another, more detailed look at it: http://www.glennchan.info/articles/t...5IREsetup.html

Last edited by Andrew Hughes; September 20th, 2010 at 02:23 PM.
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Old September 20th, 2010, 03:15 PM   #5
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hmm i've tried it on my netbook now with a fresh installation of windows 7 64bit - get the same result. black is gray.

the funny thing is: when i play the file with the original (uncompressed avi) black is black. when i play the wmv or mpeg2 version of the file, everythings is simply a bit lighter, making black in fact gray.

when i turn of the hardware accelration in Windows media player (or vlc) the black values are back to normal. this is VERY annoying :(


check this link for details:
http://forums.nvidia.com/index.php?showtopic=67285

others seem to have the same issue
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Old September 20th, 2010, 03:29 PM   #6
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ok now this really sucks :(
for some reason nvidia sets their default color range to 16-235 colors. this destroys both black and white turning everything into shades of gray.

I've found an option to correct this in the drivers control panel, but this is horrible if you give out a project to a customer as colors won't match anymore :(

has anyone had any experience with this and found a workaround? (except saving your videos as uncompressed AVIs...)

Thanks!!
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Old September 20th, 2010, 04:55 PM   #7
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I'm not sure if it's my computer's display, but that image (surrounded by the black border assume) doesn't look like it has a uniform density - it looks a bit less dense at the bottom.
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Old September 20th, 2010, 05:20 PM   #8
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yeah, but thats because its actually a gradient area with black at the bottom, and some gray at the top :)
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Old September 20th, 2010, 07:25 PM   #9
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Daniel,

For complex reasons, the US standard for black reads at 7.5 IRE (Which is the standards body "The Insitute of Radio Engineers", the body that set TV standards back in the original days TV was being established.) brightness measurement units

In Japan, which ALSO uses the NTSC color system (as we do in the US) their standards people re-set the black level at -0- IRE decades ago.

So that's the primary treason that a properly set up NTSC television system won't display 0 IRE blacks.

For a full technical discussion just type (NTSC Black Levels) into Google and you can read about the technical foundations to your hearts content.
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Old September 20th, 2010, 07:44 PM   #10
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It's a total effing mess. And the more you dig the more you're going to find out how much of a mess it really is. The best you can do, IMHO, is find out how to deliver proper black levels for your workflow. This is tedious and time consuming process. And almost any link in the production chain can change black levels.

While you're at it, you should also look at how the brightest color levels are being handled as well. Some workflows will clip them, some will lower them, some will leave them alone. Any of these options you may or may not want.

Good luck.
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Old September 21st, 2010, 02:45 AM   #11
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Quote:
Originally Posted by Bill Davis View Post
For complex reasons, the US standard for black reads at 7.5 IRE (Which is the standards body "The Insitute of Radio Engineers", the body that set TV standards back in the original days TV was being established.) brightness measurement units
He's based in Germany, so he'd come under the EBU standards.

I did a google and came up with this discussion on Video Help.

Help with video Black Levels
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Old September 21st, 2010, 04:50 AM   #12
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thanks for the link... this is worse than one of those horror-movies you hate :(

I'am producing a promo-dvd (windows based, not for the actual dvd player) menu for a musician and was quite sure, that if i encode a video to mpeg2 or lets say wmv it would play the SAME WAY on every computer (that's been installed more or less in a standard way...). Turns out that's not the case.
I have a cool menu that has a motion background and the control buttons sort of blend in - which they don't if the colors do not match anymore :(

well, at least i know it's not my pc or my eyes or something like that, it simply sucks :(

The only thing that seems to work for my project right now are uncompressed AVIs which only works from a high speed hard drive and a powerful machine, not a dvd drive in a small laptop. GIF animations (yeah.... i thought about that :/ ) aren't really capable to give the resolution that's needed, also audio runs out of sync after a while. I've tried to embed a flash object, but if you play video in there, the same thing happens to my black.

Any more ideas? :)

Thanks!
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Old September 21st, 2010, 06:12 AM   #13
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First off, turn off that nVidia setting and any other controls that will mess with your video in the background. What you need is the most 'transparent' set-up possible (by which I mean one that changes levels without you knowing as little as possible rather than it being actually transparent to view!)

Then at least what you're seeing is consistent and you can produce output that is consistent within itself.

Unfortunately, at that point it's pretty much out of your hands because whoever receives your material may well have their machine set up to an entirely different setup and it will mess with your output. Yes, this sucks.

When encoding video to wmv, my tests found that it preserved video levels across the range 0-255. But if the recipient has any kind of modification switched on eg hardware accceleration that specifically passes the video to it (eg from Media Player), and messes about with its levels in the process, then there's not much you can do. Even uncompressed AVIs might turn out to be tweaked on someone's PC.

Regards
Dave
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Old September 21st, 2010, 06:20 AM   #14
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Quote:
Unfortunately, at that point it's pretty much out of your hands because whoever receives your material may well have their machine set up to an entirely different setup and it will mess with your output. Yes, this sucks.
Hey Dave, yep, that's the problem.I've managed to configure my machine now to display it correctly (finally after all those years^^) but of course i have no influence on the setups of my customers.

I've always thought that the wmv conversion actually was the source of the problem - but it really are the shitty drivers of nvidia/ati. I really don't see why their DEFAULT setting is the 19-233 range instead of the full 0-255 colors. :(
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Old September 21st, 2010, 07:59 AM   #15
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It's a problem with any type of video production, it really depends on how the final viewer has set up their television - the variations can be pretty extreme.
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