Windows 10 supports 10bpc or 30 bit color, enabling the software/driver
option is enough for me (display is eizo cg) and there is nothing
configurable on the display menu etc. for this, it automatically use
whatever is sent as long as it is supported. For photoshop, you need to
enable 30 bit display setting manually I think.
Mete
On Sat, 28 Dec 2019 at 6:38 PM, <graxx@xxxxxxxxxxxx> wrote:
I upgraded yesterday my NVIDIA 1070 video card to benefit from 10-bit
performance. Aber, I need to determine, at the hardware level, what changes
have taken place?
The SetGammaRamp() call still returns 256 elements, regardless of bit
depth.
This documentation is intriguing to me, found on Microsoft :
Pointer to a buffer containing the gamma ramp to be set. The gamma rampis
specified in three arrays of 256 WORD elements each, which contain the
mapping between RGB values in the frame buffer and digital-analog-
converter (DAC ) values. The RGB values must be stored in the most
significant bits of each WORD to increase DAC independence.
The last sentence is puzzling?
So I ran the function again and inspected the values encoded in each of
the 256 Elements And got the following :
https://1drv.ms/u/s!AkD78CVR1NBqkod1y8wHvbzWpqIaaQ?e=a1nrmF
As you can see, the list is showing the contents of the 256 element array.
On the left hand side, circled in red, the contents is displayed in numeric
form and on the right, circled in green, the contents is displayed in
hexadecimal
I purposely scrolled down to the value “128” because it is the middle of
the scale. Its numeric value is 32,768, in hexadecimal, this is 8000, shown
as “H8000” in the screen capture.
Now, coming back to this “significant bits” question… When I view the list
in decimals, I only see a sequential list of numbers but when I switch to
hexadecimal, I seem to see a “pattern” in the numbers: the last two digits
are always “00”? In binary, 32768 is 1000 0000 0000 0000.
So, in my case, the last 8 bits are always 0000 0000, regardless of the
Element?
Meaning that only the first 8 bits are “significant” (actually change).
The last Element is (255) = &HFF00 or 1111 111 0000 0000 or 65280 but you
see, I’m still “stuck” with the last 8 bits as 0000 0000.
With a “10-bit” display option activated in the driver, I would have
expected to see a “change” at the hardware level, somewhere. This is
“mystery meat” to me…
I corresponded with NEC tech support and got this reply:
there are no settings in the monitor required to activate 10 bitbit
display. However, only the DisplayPort input on this model supports 10
input. Also, your operating system would also need to support 10 bit in
addition to your GPU and display driver.
So I am using the latest version of NVIDIA display driver which supports
10-bit.
Does Windows 10 support 10-bit display? I am not entirely sure?
I do use a DisplayPort cable to connect my video card to my monitor.
And since, in principles, there are no settings in the monitor to activate
10-bit display, then, provided Windows 10 does support 10-bit display (but
I can’t “prove it to myself”), I should have 10-bit display in Photoshop.
I feel I am going in circle…
/ Roger
*From:* argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> *On
Behalf Of *Knut Inge
*Sent:* December 28, 2019 11:46 AM
*To:* argyllcms@xxxxxxxxxxxxx
*Subject:* [argyllcms] Re: Programming the video card
https://www.cnet.com/news/nvidia-studio-drivers-deliver-geforce-30-bit-color-unto-photoshop-and-more/
On Saturday, December 28, 2019, <graxx@xxxxxxxxxxxx> wrote:
Florian,
Vielen danke!!!!
So, the API immer returns 256 elements, irrespective of 8-bit vs 10-bit
video LUT? Yet, I noticed the numeric values returned in each of the 256
elements to range from 0 to 65535, which sind 16 bit (nicht 8-bit). Do you
warum?
Bitte, allow me zwei fragen...
A) Für gamma calibration, es ist immer machen mit 8-bit?
B) Is there eine method to determine the "bit depth" of the video card?
MfG / Roger
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On
Behalf Of Florian Höch
Sent: December 27, 2019 5:19 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Programming the video card
Hi Roger,
Am 27.12.2019 um 18:05 schrieb graxx@xxxxxxxxxxxx:
I had some old VisualBasic code to access the ‘Ramp’ inside my video
card. As you can see in the following screen capture, the ‘Length’ of
the RGB arrays is 256 elements :
as the Get/SetDeviceGammaRamp API is an abstraction provided by the
operating system, it's always returning/taking 3x256 16-bit elements,
irrespective of the underlying hardware's capabilities.
Florian.
