User Manual

Practically speaking, this makes controls that operate by letting you make adjustments
at different tonal ranges, such as Custom Curves, Soft Clip, and so on, work more
easilywith wide-latitude signals.
3 When you’re happy with the HDR grade, choose “Target Display Output” and “Trim
Controls For” settings that you want to trim to. By default, these are set to “100-nit,
BT.709, BT.1886, Full,” which is a typical SDR deliverable. However, other options
are available if you want to do multiple trim passes to obtain a more accurate result.
Whichever setting you choose from, “Trim Controls For” dictates which trim pass you’re
doing. You can do multiple trim passes by choosing another option from this menu.
4 Click the Analysis button in the Dolby Vision palette. This analyzesevery pixel of every
frame ofthe current shot, and performs and stores a statistical analysisthat is sent to
the CMU to guide itsautomatic conversion of the HDR signal to an SDR signal.
5 If you’re not happy with the automatic conversion, use the Lift/Gamma/Gain/Chroma
Weight/Chroma Gain controls in the Dolby Vision palette to manually “trim” the result to
the best possible Rec. 709 approximation of the HDR grade you created in step 1. This
stores what Dolby refers to as “artistic guidance” metadata.
6 If you obtain a good result, then move on to the next shot and continue work. If you
cannot obtain a good result, and worry that you may have gone too far with your HDR
grade to derive an acceptable SDR downconvert, you can always trim the HDR grade
a bit, and thenretrim the SDR grade to try and achieve a better downconversion.
Dolby recommends that if you make significant changes to the HDR master, particularly
if you modify the blacks or the peak highlights, you should reanalyze the scene.
However, if you only make small changes, then reanalyzing is not strictly required.
As you can see, the generalidea promoted by Dolby is that a colorist will focus on gradingthe
HDR picture relative to the 1000, 2000, 4000, or higher nit display that is being used, and will
then relyonthe colorist to use the Dolby Vision controls to “trim” this into a 100 nit SDR
versionwith artistic guidance. This “artistic guidance” metadata is saved as part of the mastered
media, and it’s used to more intelligently scale the HDR highlights to fit within any given HDR
display’s peak highlights, to handle how to downconvert the image for SDR displays, and also
how to respond when a television’s ABL circuit kicks in. In all of these cases, the colorist’s
artistic intent is used to guide all dynamic adjustments to the content.
Delivering Dolby Vision
Once you’re finished grading the HDR and trimming the SDR downconversion, you need to
output your program correctly in the Deliver page.
Rendering a Dolby Vision Master
To deliver a Dolby Vision master after you’ve finished grading, you wantmake sure that the
Output Color Space of the Color Management panel of the Project Settings is set to the
appropriate HDR ST.2084 setting based on the peak output you want to deliver (any values
above will be clipped). Then, you want to set your render up to use one of the following Format/
Codec combinations:
TIFF, RGB 16-bit
EXR, RBG-half (no compression)
When you render for tapeless delivery, the artistic trim (level 2) metadata is rendered into a
Dolby Vision XML and delivered with either the Tiffs or EXR renders. These two sets of files are
then delivered to afacility that’s capable of creating the Dolby Vision Mezzanine File (this
cannot be done in Resolve).
Chapter – 8 HDR Setup andGrading 251