©2018 NEC Display Solutions, Ltd.
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7 Miscellaneous Configuration Items
Note:
Many of the options for the Raspbian OS can be automatically configured using the Compute
Module Configuration Tool for Raspbian see “Compute Module Configuration Tool for Raspbian” on
page 65.
7.1 Configuring the correct HDMI video level encoding and decoding
The Compute Module can output video to displays that have video levels either in the range 0-255
(known as “full”) or in the range 16-235 (known as “limited” or “RGB limited”). Configuration settings for
the OS determine which range will be output. The NEC display can accept either range sets and will
display the video correctly, as long as it is configured correctly to match the video range from the
Compute Module. However, it is recommended to use the “full” range since it will give the maximum
number of displayable colors.
A mismatch between the output range from the Compute Module and the display will result in either:
•
Blacks appearing as gray and whites being too dark.
o
Cause: Compute Module outputs “limited” video range and the display is set to “RAW”.
Or
•
Dark gray levels being crushed and whites being clipped.
o
Cause: Compute Module outputs “full” video range and the display is set to “Expand”.
The video range used by the display is configured as follows:
1.
Navigate to the
MULTI INPUT
menu on the OSD.
2.
Select
TERMINAL SETTINGS
.
3.
The
VIDEO LEVEL
setting determines how the display will handle the video from the Compute
Module.
•
RAW
- Use
RAW
if the Compute Module is configured to output “full” video in the range 0-
255.
This is the recommended configuration since it provides the maximum number of
displayable colors.
The display will not modify the range of the video signal levels.
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