INSTALLATION AND OPERATION GUIDE
156 | XIP-3901
APPENDIX C: BBC HLG Look-Up Table
Introduction
To facilitate the introduction of HLG production, the XIP-3901-UDC-HDR option now includes the BBC R&D look-
up tables (LUTs) release v1.4 which implement a range of key format conversions. The conversions are 33-cube
3D-LUTs including:
•
BT.2100 PQ (1000 cd/m
2
nominal peak) to BT.2100 HLG
•
BT.2100 PQ (4000 cd/m
2
nominal peak) to BT.2100 HLG
•
BT.709 (SDR) to BT.2100 HLG (display-referred direct mapping maintaining SDR "look")
•
BT.709 (SDR) to BT.2100 HLG (scene-referred direct mapping for matching cameras)
•
BT.709 (SDR) to BT.2100 HLG (display-
referred “up-mapping”/ “inverse tone mapping” to maintain SDR
artistic intent)
•
BT.709 (SDR) to BT.2100 HLG (scene-
referred “up-mapping”/ “inverse tone mapping” for matching SDR
and HDR cameras)
•
BT.2100 HLG to BT.2100 PQ (1000 cd/m
2
nominal peak)
•
BT.2100 HLG to BT.709 (SDR) (display-
referred “down-mapping”/ “tone mapping” maintaining HDR
"look")
•
BT.2100 HLG to BT.709 (SDR) (scene-
referred “down-mapping”/ “ tone mapping” to match SDR
cameras)
•
S-Log3 SR-Live (BT.2020 color) to BT.2100 HLG (scene-referred conversion to match BT.2100 HLG
cameras)
The scene-light LUTs will only work correctly with ITU-R BT.2100 signals. They will not color match cameras
configured for Sony’s “HLG Live” variant, nor the “Traditional Color” variant of HLG specified in ITU-R report
BT.2390, described as “HLG Vivid” in Canon cameras.
LUT Details
Of the various licensed LUT from the BBC, the XIP-3901 will use Type II LUTs that are intended for full-range SDI
input signals such as S-Log3 and those produced by some PQ devices and Type III LUTs are intended for LUT
devices that process narrow-range video signals, but which operate over the full 10-bit signal range (0 to 1023).
They will therefore pass sub-blacks (signals below 10-bit code value 64) and super-whites (signals above 10-bit
code value 940) (required for ITU-R BT.814 HDR PLUGE and ITU-R BT.2111 HDR Color Bars), so are most
suitable for broadcast TV applications.
Figure 108
Type II signal scaling, intended for full-range input signals (for example, S-Log3)
3D-LUT
Matrix
1023
0
Y
'
C
'
B
C
'
R
Input Signal Range:
Full
LUT Mode:
Full
1023
0
R
'
G
'
B
'
0
1
940
64
Matrix
1023
0
R
'
G
'
B
'
940
64
1023
0
Y
'
C
'
B
C
'
R
Scale Output
(0 - 1023)
Output Signal Range:
Narrow
940
64
1019
4
Clip to SDI
Range
Y
'
C
'
B
C
'
R
Type II
Normalisation
(0 - 1)
Input
Input signal and
processing range
Output
Nominal output
signal range
Processing
range
