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Lut files, Lut file format specification – AJA KONA 4 PCI-E Video I/O Card (HDMI Output, Cable Included) User Manual

Page 54

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KONA Capture, Display, Convert v15.5 54 www.aja.com

Reset

Clicking on the Reset button resets the currently selected LUT Type to its default

values (not active for a User LUT file).

LUT Files

The User LUT File setting above activates the LUT Files dropdown, allowing the

selection of a previously saved LUT file. You can create a custom LUT file using

most text editors or spread sheets, provided the data is arranged according to the

LUT File Format Specification that follows (see

"LUT File Format Specification" on

page 54

).

Uploading Custom User LUT file

Once the LUT file is created, you can upload it with the following steps:
1. Before loading a LUT, make sure you are using an RGB/RGBA framebuffer

format, and that you have a AJA Video Device that supports LUTs.

2. Open AJA Control Panel and select the “LUT” pane.
3. Click the “LUT Type” popup and choose “User LUT File” menu item. Note

“LUT Files” options become enabled.

4. Click the “+” button and use the navigation dialog to choose a custom LUT

file. The LUT is now loaded.

LUT File Format Specification

LUT files are normal text files that contain 1025 lines (numbered 0 - 1024). Each

line contains 3 integer values in the range 0 - 1023, representing 10 bit R, G, B

component output values. Component values may be separated by one or more

commas, spaces, or tabs. The example below show LUT File contents for Line 0,

Line 1, Line 2, and Line 1024, with several valid ways to separate the numbers in a

line.

• 16, 17, 17
• 17 18 18
• 19 19 21
• …
• 1000, 1022, 1023

In the example above, the first line (Line 0) represents the output values for the

case where R=0, G=0, or B=0. In other words, if the R component of a pixel is set

to 0, then set R component value to 16. Likewise, if G is set to 0, then set G to 17.

The second line

(Line 1) does a similar thing for input component values equal to 1.
A simple way to construct a LUT file is to use a Spreadsheet like Excel. Simply fill 3

columns and 1025 rows with LUT data, and save the result as a “CSV” file.