Hello,
Model # searched: TX55CX400E -- TX55CX400B doesn't exist in Panasonic's database.
Page 16; Sources:
"Enables or disables selected source options. There are Regular, Enhanced and
Disabled options available for HDMI sources. Regular and Enhanced options are
affecting the colour settings of the selected HDMI source. To be able to watch 4K
images from a HDMI source related source setting should be set as Enhanced if the
connected device is HDMI 2.0 compatible. Set as Regular if the connected device is
HDMI 1.4 compatible. Set acoordingly or disable the related HDMI source by setting
as Disabled."
Source:
https://dlc.panasonic-europe-service.com/EUDocs/GetDoc.aspx?did=245454&fmt=PDF&lang=en&src=3&uilang=en-GB&model=TX55CX400E
All the best!