R How Do You Deliver HDR?
Now that the boring stuff is out of the way, let’s
go back to your customer. The customer wants
HDR. How are you going to give him HDR? The
camera you already own may be HDR-ready,
and it won’t cost you anything to enable HDR
recording, although you will likely need some
extra cash for additional hardware on the post-production end of things. But we’re not there yet.
Here’s a simple breakdown of an HDR workflow. The camera should be capable of recording in a minimum 10-bit RAW format or even
HLG natively. Nearly every digital cinema
camera worth its salt records in one RAW format or another. Blackmagic shoots DNG. ARRI
and RED have proprietary formats. The popular
Panasonic GH series mirrorless cameras can
In case RAW footage is a mystery to you,
here’s an explanation. Instead of encoding the
recording in a continuous video format, the image is recorded as a series of still frames. This
is equivalent to shooting with a still camera in
burst mode, but with very fast frame rates and
very large images.
The single biggest advantage is the same reason why pro photographers always shoot in RAW.
The camera does not process the image from the
sensor but instead leaves it as a raw (hence the
name) representation of what the camera saw.
Your final output then has the greatest amount
of latitude and flexibility in post-processing. The
image is very flat, almost grayscale in some cases, but that allows you, the creative, to add back
in the color and contrast that you want.
The biggest disadvantage to this type of shooting is having to deal with extraordinarily large
file sizes and processing requirements in post.
You will need a very fast rig for editing. Alternatively, you can use something like Premiere
Pro’s auto-ingest transcoding to re-encode your
RAW footage into intermediate files, which will
make editing more tenable for older systems.
The RAW video will then be imported into an
NLE capable of working with RAW footage and
grading in the color space(s) required by HDR.
Depending on your preferred post-production
software, this could mean editing in one app and
grading in another. All of the major NLEs currently support at least one form of HDR grading.
Since Dolby Vision is a proprietary format, it
requires Dolby hardware, Dolby software, and
Dolby metadata. Suffice to say, we’re going to
leave the Dolby workflow out of this explana-
tion. I believe if you have the resources to work
in Dolby Vision, the company will send a team
of people to teach you everything you need to
know about working in its software.
One final note on how the various HDR standards differ. The processing and interpreting
of the HDR signal is different. Some standards
like Dolby Vision perform a scene-based analysis and utilize dynamic metadata to dictate
how the image displays on final output. Others
like HDR10 use static metadata. But HDR10+
offers dynamic metadata and analyzes by scene
or even by frame, making it more comparable
to Dolby Vision.
For my test workflow, I chose the Blackmagic
DaVinci Resolve system. As previously mentioned, there are ways of generating HDR video
in other software, but Resolve has been around
longer than all of them and is a household name
when it comes to color grading. Setting up the
project and physical work environment is critical to working in HDR. If you’re already a color-conscious editor, you know the value and importance of having a properly lit workspace for
grading. This is no different, but HDR did require
some additional hardware in my case.
Here’s the good news: I managed to stretch
my 2013 MacBook Pro’s lifespan a little longer
and found that I could still work with HDR footage without it bogging down. (4K is another matter and another article altogether.)
What about cabling? I have an HDMI cable
that is capable of handling full 4K resolutions,
HDCP, up to 32 audio tracks, and a whopping
48-bit color. You may be thinking that this cable cost as much as a Vespa scooter, weighs as
much, and is made of melted-down, solid gold,
Jackson 5 records. You would be wrong. It was
$11.99 on Amazon, and it handles HDR just fine.
Like me, you may have been spoiled for years
by not needing any external video interface devices to display your content, but my setup for
HDR work in Resolve required either a Blackmagic DeckLink 4K Extreme 12G or an UltraStudio 4K Extreme video interface. The DeckLink 12G is a PCIe card that takes HDMI from
the computer and outputs an SDI or HDMI signal to an external HDR-capable monitor. The
UltraStudio basically accomplishes the same
task but with a Thunderbolt connection instead.