Producing and Grading HDR

The Hard Part: Actually Grading Your Footage

Now that you’ve got hardware all set up and arranged nicely, it’s time to get down to the nitty-gritty of bringing out those beautiful, vibrant colors and highlights. Here’s where things get complicated. As mentioned previously, there are still several HDR standards that you can use, so these next steps will vary depending on which road you take.

For my example, I’m grading for the open HDR10 standard. There are three basic properties for this standard: up to Rec. 2020 color space, 10-bit color, and SMPTE ST.2084 (PQ) transfer function. Rec. 2020 supports frame sizes of 3840x2160 and 7680x4320 (8K), frame rates up to 120p, and bit depths up to 12-bit. I didn’t want to put that much technical detail into this article, but I learned right away that in order to properly understand and work with HDR, it’s required reading.

Setting up Resolve requires having at least a basic understanding of these specs and applying them when setting up your project. Unfortunately, there’s no HDR on/off toggle button in a menu. However, there are two toggles in Resolve that you’ll need to turn on (Figure 1, below): Enable HDR metadata over HDMI (if using an HDMI out from your workstation) and HDR mastering is for (insert nits level here).

Figure 1. Enabling HDR metadata over HDMI in Blackmagic DaVinci Resolve

Speaking of nits, setting your nit max level is important for ensuring that what you put into your grade reproduces faithfully on the end-user’s display. Typically, we’re grading for consumer televisions or maybe computer monitors. Good consumer sets generate about 600 nits of peak brightness while the best can hit 1,000. Setting your top end at 1,500 or 2,000 nits can result in the viewer losing out on the top end of your highlights since the set will clip those values.

Resolve offers extensive options for setting up for HDR grading. First, you’ll set the Color Science of your project to DaVinci YRGB Color Managed (Figure 2, below). This is found under the Project Settings. Then choose the ST.2084 specific setting that corresponds to your display. In my case, I chose the ST.2084 1,000 nit since that’s what the SmallHD display is capable of. Next, select the Timeline Color Space that you want to work in and will be assigned to your final output. In Resolve, the gamma and color space can either be the same or be chosen differently.

Figure 2. Color management project settings in Blackmagic DaVinci Resolve

One warning about working in Resolve: Your standard computer monitor will still show a flat, RAW-like image of your content, but the HDR display will appear correct with the grade. The “magic” of the conversion from flat to HDR actually happens in the display. If you want your computer monitor to simulate the HDR image, you can use a 3D LUT (Figure 3, below). You’ll find this setting back in the Color Management page under Project Settings. You can choose the setting that matches the HDR display you’re using. Again, my example is ST.2084 1,000 nits.

Figure 3. 3D LUT options in DaVinci Resolve

Once your settings are all done (Figure 4, below), your scopes will reflect the available range of each property for your footage by adjusting the size of your waveforms accordingly within the scope (Figure 5, below Figure 4). Grade away.

Figure 4. Enabling HDR scopes in the DaVinci Resolve Color Settings

Figure 5. DaVinci Resolve scopes showing a broadened nit range

With all this talk about HDR, standards, color space, and gamma, it’s important to remember that by the time you read this it will likely be out of date in at least one or two areas. In fact, our own beloved Jan Ozer wrote about this very topic only a year ago (http://go2sm.com/4t). Within the month the article was posted online, comments were posted about two items that were already out of date. Even my own humble take on HDR in 2018 will likely be dated by the time the ink dries on this issue of Streaming Media. While the technical details may share the same fate, the principles and workflow won’t change much, if any.

Like the glorious standards battles of our noble past (Blu-ray vs. HD-DVD, VHS vs. Betamax), HDR will continue to be a hill that companies will die on until (hopefully) one format will rise victorious. On the bright side, there’s more interoperability among HDR standards than we would find with previous format wars. For example, Dolby Vision television sets are “backward-compatible” with HDR10 content.

At the time of this writing, the newest TV sets being announced and planned for release in 2018 are confirming their support for HDR10+. Even older sets will have firmware updates released that will allow them to display the newer 10+ format. So although the standards may come and go, with the right know-how, you can be ready to produce HDR when your clients ask for it.