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HDMI cable vs DVI, and black levels... makes a difference?

captaintrips
Explorer
Reading around, it appears using a straight DVI cable from the rift to your gpu instead of HDMI provides darker black levels, where as using HDMI (or the HDMI to DVI adapter included with the rift) produces lighter/gray black levels.
And this is more apparent if your downsampling from higher resloutions.

I'm assuming the rift requires a duallink DVI cable, and not just any standard one, based on the pinout on the DVI port on the back of the controller, but before I invest into such... is this correct? any merit to these rumors?
10 REPLIES 10

geekmaster
Protege
HDMI depends on video card settings. There is a 0-255 range, and a 16-235 range. It makes a huge difference in black levels. Some video drivers switch modes depending on video content, such as movies.

You can read more about it here:
viewtopic.php?f=34&t=1130&p=12637#p12637
viewtopic.php?f=26&t=103&p=14892#p14892
https://forums.geforce.com/default/topic/515921/hdmi-output-video-levels-16-235-vs-pc-levels-0-255-/
http://en.wikipedia.org/wiki/Rec._709

captaintrips
Explorer
thanks geekmaster!

Now the the next question... do I need a dualink dvi cable for the rift, or will a standard dvi cable work?

geekmaster
Protege
"captaintrips" wrote:
thanks geekmaster!

Now the the next question... do I need a dualink dvi cable for the rift, or will a standard dvi cable work?

What? Is your Google-Fu broken or something? :lol: It gets better with practice, you know... 😉

Standard Single-Link DVI is fine.
"
You will see that the Rift is missing extra pins needed for Dual-Link DVI. So yes, Single-Link DVI i...

MorbidDonkey
Heroic Explorer
"geekmaster" wrote:

What? Is your Google-Fu broken or something? :lol: It gets better with practice, you know... 😉


Now that this is answered and on the internet you will now be immortalized for answering this question! You are now ONE with the Google. Mind....Blown! :shock:
-: MorbidDonkey :- =================================== LOGISTICS - Oculus Prototype 1

captaintrips
Explorer
Yep, Geekmaster just made history. Anytime someone thus forth googles said question, they now have a immediate first link page with an answer.


With that said, it will still not stop the inevitable 30+ further threads questioning the same damn thing.

philipcu
Honored Guest
If you are using NVidia drivers - I've recently found a way to get the colour to be much richer and the blacks a lot more black on an HDMI cable.
In the drivers select: Display > Adjust desktop color settings. Then select "Rift DK", scroll down to the bottom where it says "Digital color format" and select "YCbCr444"

KBK
Protege
"philipcu" wrote:
If you are using NVidia drivers - I've recently found a way to get the colour to be much richer and the blacks a lot more black on an HDMI cable.
In the drivers select: Display > Adjust desktop color settings. Then select "Rift DK", scroll down to the bottom where it says "Digital color format" and select "YCbCr444"



HDMI is a consumer interface.

Film has a black level issue. In the video and CRT display industry, at the pro level...they have two settings for black level.

0 IRE and 0.7 IRE. 0.7 IRE is the elevated black level. 0 IRE is the true black level.

Some Blu-rays and DVD's have elevated black levels, some do not. Your given DVD and bluray player has as an adjustment in the settings, for this exact issue.

It should be on the top menu, as the problem is variable from disc to disc, film to film. It is a true standard, it is just that it has two settings.

Since this is all computer based with the Rift, the default setting of the HDMI out on the given GPU, which appears to be an elevated black level, this seems to be the creation of an issue for the rift's scaling hardware (outboard LVDS box). The default is the elevated level, a consumer standard application.

444 is pro level output, which is full scale, maximum delineation and ranging, editing level, etc..which defaults to 0IRE black level.
Intelligence... is not inherent - it is a point in understanding. Q: When does a fire become self sustaining?

feysal
Honored Guest
You can read more about dvi vs hdmi at Techie Lens.

AntDX3162
Heroic Explorer
I think the biggest difference would be if the panel is HDR or not but I haven't really seen an HDR monitor in real-life.  The difference looks a lot in terms of color depth and brightness.  Those 4k 21:9 HDR panels coming out for like $5k each.
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