User Manual

Rendering an Ordinary SDR Media File
If you want to export the SDR trim pass, then you can choose HDR10+ from the Tone Mapping
drop-down menu in the Advanced Settings of the Render Settings list on the Deliver page, and
choose the 100-nit, BT.709, BT.1886, Full setting below. With this enabled, you can output the
SDR version of your program to any format you like.
The Tone Mapping setting in the Advanced Settings of the Render Settings list
Hybrid Log-Gamma (HLG)
The BBC and NHK jointly developed another method of encoding HDR video, referred to as
Hybrid Log-Gamma (HLG). The goal of HLG was to develop a method of mastering HDR video
that would support a range of displays of different peak luminance capabilities without
additional metadata, that could be broadcast via a single stream of data, that would fit intoa
10-bit signal, and that in the words of the ITU-R Draft Recommendation BT.HDR, “offers a
degree of compatibility with legacy displays by more closely matching the previous established
television transfer curves.”
The basic idea is that the HLG EOTF functions very similarly to BT.1886 from 0 to 0.6 of the
signal (with a typical 0–1 range), while 0.6 to 1.0 smoothly segues into logarithmic encoding for
the highlights. This means that, if you just send an HDR Hybrid Log-Gammasignal to an
SDRdisplay, you’d be able to see much of the image identically to the way it would appear on
an HDR display, and the highlights would be compressed to present an acceptable amount of
detail for SDR broadcast.
On a Hybrid Log-Gamma compatible HDR display, however, the log-like highlights of the image
(not the BT.1886-like bottom portion of the signal, just the highlights) would be stretched back
out, relative to whatever peak luminance level a given HDR television is capable of outputting,
to return the image to its true HDR glory.This is different fromthe HDR10 method of distribution
described previously, in which the graded signal is referenced toabsolute luminance levels
dictated by ST.2084, andlevels that cannot be represented by a given display will be clipped.
And while this facility to support multiple HDR displays with differing peak luminance levels is
somewhat analogous to Dolby Vision’s ability to tailor HDR output to the unique peak luminance
levels of any given Dolby Vision-compatible television, HLG requires no additional metadata to
guide how the highlights are scaled, which depending on your point of view is either a benefit
(less work), or a deficiency (no artistic guidance to make sure the highlights are being scaled in
the best possible way).
As is true for most things, youdon’t get something for nothing. The BBC White Paper WHP 309
states that, for a 2000 cd/m2 HDR display with a black level of 0.01 cd/m2, up to 17.6 stops of
dynamic range without visible quantization artifacts (“banding”) is possible. BBC White Paper
WHP 286 states that the proposed HLG EOTF should support displays up to about 5000 nits.
So, partially, the backward compatibility that HLG makes possible is due in part to discarding
long-term support for 10,000 nit displays. However, it’s an open question whether or notover
5000 nits is even necessary for consumer enjoyment.
Sony, LG, Panasonic, JVC, Phillips, Hisense, Hitachi, and Toshiba have all either announced or
are shipping consumer HDR televisions capable of displaying HLG encoded video, and of
course DaVinci Resolve supports this standard through Resolve Color Management.
Chapter – 8 HDR Setup andGrading 258